NHÂN CA LỒNG RUỘT RUỘT THỪA tại MEDIC

Appendiceal Intussusception into Cecum: Case Report, Ly Van Phai, Le Thi Quynh Nhu, Nguyen Thien Hung, Phan Thanh Hai, Medic Medical Center, Ho Chi Minh City, Viet Nam

Abstract

Appendiceal intussusception is not a common disease and is rarely diagnosed preoperatively. In our case, a 25-year-old male patient living in Ho Chi Minh City came to Medic Medical Center complaining about his epigastric abdominal pain, which lasting for 3 days. His body temperature was not high and he did not have any other symptoms. He recalled similar pain which had gone away without any treatment three months ago. Abdominal ultrasound showed abnormalities in appendix and cecum. During performing colonoscopy, we suspected appendiceal intussusception, and following computed tomography showed the images of enlarged appendix with fluid-filled lumen and signs of intussusception at the appendix base. The patient underwent an operation to remove the appendix and appendiceal intussusception was confirmed. Microscopic result was consistent with chronic appendicitis.

Intussusception of the appendix vermiformis in adults is a rare condition caused by anatomical and pathological factors such as tumors and is rarely diagnosed before surgery.

Although most appendiceal tumors are benign, tubular adenoma is an unusual lesion. Furthermore, carcinoma of the appendix is a distinctly rare phenomenon. The combination of both a carcinoma and intussusception has been regarded as extremely rare. Here, we report a case with intussusception of the appendix induced by primary appendiceal adenocarcinoma and discuss the clinical features, classification, preoperative diagnosis and therapy of this condition together with a review of the literature.

 

 

DISCUSSION

Intussusception of the appendix is an uncommon pathological condition. The incidence of invagination of the appendix is 0.01% in a large autopsy series. The etiology of appendiceal intussusception has been proposed by Fink et al. to be divided into anatomical and pathological causes. Anatomical variations include a fetal-type cecum, a wide appendicular lumen and a thin, mobile appendix. Reported pathological conditions include worms, endometrial implants and tumors. Various classifications of appendiceal intussusception have been attempted. Forshall divided cases into a primary type and a secondary or compound type. Langsam et al. classified the disorder into four types according to the relationship of the intussusceptum and intussuscipiens. In our case, the appendiceal tumor as a leading point seemed to have induced the complete appendiceal intussusception.

Preoperative diagnosis of intussusceptions of the appendix is often difficult because it is a rare clinical entity; only a few cases can be diagnosed by barium enema and colonoscopy. Many cases have been diagnosed as filling defects or polypoid tumors of the cecum. Careful endoscopic examination, identifying the appendiceal orifice, should be required in the case of cecal polyp. When differential diagnosis is difficult, computed tomography or abdominal ultrasound is more useful. A definite finding of intussusception of the appendix in CT is the invaginated appendix in the cecal cavity.

Tumors of the appendix are uncommon; also, most tumors are benign. Adenoma of the appendix is also a rare condition. Only 50 cases of appendiceal adenoma were reported among 30 000 appendectomies. Moreover, primary adenocarcinoma is a very rare entity, which in most cases arises from a pre-existing adenoma. Ohno et al. first reported appendiceal intussusception induced by tubulovillous adenoma with carcinoma in situ similar to our case; the combination of both a carcinoma in adenoma and intussusception has been regarded as extremely rare.

Treatment of appendiceal intussusception is mainly surgical. The procedure varies from reduction of intussusception with appendectomy to right hemicolectomy. A right hemicolectomy or ileocecal resection with lymph node dissection should be performed when carcinoma is diagnosed preoperatively or during surgery. In the last decade, laparoscopic procedures have been applied to the treatment of almost all colonic diseases, including both benign and malignant lesions. As Schmidt et al. reported laparoscopic management of appendiceal intussusception, laparoscopic procedures will be more useful as a minimally invasive treatment.

The clinical manifestation of appendiceal intussusception with primary appendiceal tumor resembles a large cecal polyp with a wide stalk, but its treatment is completely different. Endoscopic removal should be performed carefully in cases of polypoid lesions in the cecum, taking into consideration the possibility of an invaginated appendix. Failure to recognize this condition may result in unexpected complications such as consequent peritonitis.

 

VIÊM RUỘT THỪA CẤP Ở TRẺ EM: NÊN KHÁM SIÊU ÂM TRƯỚC TIÊN

Sonography is widely available, can be performed at the bedside, involves a short acquisition time, does not use ionizing radiation, is relatively inexpensive, and may show evidence of other causes of abdominal pain. It is particularly useful in evaluating young women, in whom the radiation dose to the reproductive organs should be minimized and for whom it is important to exclude ovarian and uterine conditions that might mimic appendicitis. There have been multiple studies evaluating the value of sonography in the evaluation of appendicitis, showing varying sensitivity, specificity, and accuracy. However, a recent study by Pacharn et al found that sonography for acute appendicitis had a negative predictive value of 95%, making it an excellent screening tool in the evaluation of acute appendicitis. Goldin et al suggested that standardizing the technique and criteria will decrease variability in the diagnostic accuracy of sonography across institutions.

Technique

The standard sonographic evaluation of the abdomen based on the American Institute of Ultrasound in Medicine practice guideline includes imaging of the appendix. A complete abdominal sonographic examination does not need to be performed in the evaluation of acute appendicitis.

However, because the appendix is not always located in the right lower quadrant and an abscess could be present, imaging should include not only the right lower quadrant but also the pelvis and left lower quadrant. A survey of the abdomen for free fluid or bowel thickening elsewhere is also helpful, especially in cases of suspected perforation.

At the start of the examination, it is helpful to ask the patient to point to the site of maximal tenderness and begin scanning in this location. Using a high-resolution linear transducer, the abdomen should be compressed while scanning, which moves bowel gas out of the field of view. This compression sonography is performed with an empty bladder. The most reliable way to identify the appendix is to find the ascending colon, follow the colon proximally to the cecum, and then find the appendix extending off the cecum.

If the appendix cannot be seen in the supine position, it may be helpful to place the patient in the left lateral decubitus position to cause a retrocecal appendix to be better seen.

Scanning with a full bladder may also be helpful because it can better delineate a deep pelvic appendix that might be obscured by overlying bowel.

The complete appendix should be visualized, including the tip. The maximal outer wall diameter should be measured, and the wall thickness should be measured along the course of the appendix. The normal maximal outer wall diameter of the appendix is less than 6 mm, and the mural thickness is less than 2 mm (Figure 1A). Compression of the appendix should be performed, with documentation of the appearance of the appendix during compression. A normal appendix compresses (Figure 1B). Secondary signs such as free fluid, a fecalith, and hyperechoic surrounding fat should be documented. Doppler imaging is helpful to evaluate for hyperemia; however, a necrotic appendix will have decreased or no blood flow. Video clips should be obtained to show normal peristalsis unless the physician is present during the scan. If an abscess is suspected, a lower- frequency curved array transducer may be used for a larger field of view and deeper penetration.

It is not always necessary to identify a normal appendix to consider the findings negative.  If there are no secondary signs as mentioned above, and clinical suspicion is moderately low for appendicitis, many institutions stop the evaluation and consider the sonographic findings negative for appendicitis.

In the setting of acute appendicitis, the appendix is noncompressible, and the maximal outer wall diameter is greater than 6 mm (Figure 2). An appendicolith may be present, helping the diagnosis (Figure 3); however, an appendicolith can be present without acute appendicitis, and the presence of an appendicolith does not confirm acute appendicitis.

There may also be secondary signs of inflammation, such as hyperechoic surrounding fat, free fluid, or an abscess (Figure 4). The wall may be hyperemic (Figure 5). Enlarged nodes can also be seen in the right lower quadrant, but this finding is nonspecific and can also be seen in patients without appendicitis. The surrounding bowel may be dilated with loss of normal peristalsis due to ileus.

Conclusions

Right lower quadrant sonography, when performed using rigorous technique and criteria for diagnosis, is an excellent screening tool for acute appendicitis. This examination is quick and painless and does not involve the use of ionizing radiation. Although the sensitivity, specificity, and accuracy of sonography vary greatly in studies evaluating the imaging diagnosis of acute appendicitis, it should be the first imaging modality when there is clinical concern for acute appendicitis. Only if the examination is equivocal or if the appendix cannot be identified should other imaging modalities such as CT be considered.

J Ultrasound Med 2012; 31:1153–1157 | 0278-4297 |www.aium.org

Valve of Gerlach/appendiceal orifice Joseph von Gerlach Joseph von Gerlach (1820-1896)

Appendiceal orifice (arrow) and water filled cecum.

Joseph von Gerlach (April 3, 1820 – December 17, 1896) was a German professor of anatomy at the University of Erlangen. He was a native of Mainz, Rhineland-Palatinate. Gerlach was a pioneer of histological staining and anatomical micrography. In 1858 Gerlach introduced carmine mixed with gelatin as an histological stain.[1] Along with Camillo Golgi, he was a major proponent of the theory that the brain's nervous system consisted of processes of contiguous cells fused to create a massive meshed network. Gerlach summed up his theory by stating: the finest divisions of the protoplasmic processes ultimately take part in the formation of the fine nerve fibre network which I consider to be an essential constituent of the gray matter of the spinal cord. The divisions are none other than the beginnings of this nerve fibre net. The cells of the gray matter are therefore doubly connected by means the nerve process which becomes the axis fibre and through the finest branches of the protoplasmic processes which become a part of the fine nerve fibre net of the gray matter. The reticular theory predominated until the 1890s when Ramon y Cajal brought forth his neuron doctrine of synaptic junctions, which in essence replaced the reticular theory. Gerlach was one of the first physicians to use photomicrography for medical research. In 1863 he published a handbook titled Die Photographie als Hilfsmittel mikroskopischer Forschung (Engl. "Photography as a tool in microscopic science") in which he discusses the practical and technological aspects of microscopic photography. The eponymous "Gerlach's valve" (valvula processus vermiformis) is named after him. This anatomical structure is a fold of membrane sometimes found at the opening of the vermiform appendix.[2] In his article Ueber das Hautathmen[3] (Engl. "On skin respiration") he was the first to show that human skin uses oxygen from ambient air.

COMPARISON SWE to STRAIN ELASTOGRAPHY for THYROID NODULES

Abstract

Although elastography can enhance the differential diagnosis of thyroid nodules, its diagnostic performance is not ideal at present. Further improvements in the technique and creation of robust diagnostic criteria are necessary. The purpose of this study was to compare the usefulness of strain elastography and a new generation of elasticity imaging called supersonic shear wave elastography (SSWE) in differential evaluation of thyroid nodules. Six thyroid nodules in 4 patients were studied. SSWE yielded 1 true-positive and 5 true-negative results. Strain elastography yielded 5 false-positive results and 1 false-negative result. A novel finding appreciated with SSWE, were punctate foci of increased stiffness corresponding to microcalcifications in 4 nodules, some not visible on B-mode ultrasound, as opposed to soft, colloid-inspissated areas visible on B-mode ultrasound in 2 nodules. This preliminary paper indicates that SSWE may outperform strain elastography in differentiation of thyroid nodules with regard to their stiffness. SSWE showed the possibility of differentiation of high echogenic foci into microcalcifications and inspissated colloid, adding a new dimension to thyroid elastography. Further multicenter large-scale studies of thyroid nodules evaluating different elastographic methods are warranted.

Methods

During a few weeks trial time in 2010, four consecutive patients with single thyroid nodule (n = 1) and nodular goiter (n = 3) were evaluated. Approval for this study was obtained from the Ethics Committee of the Medical University of Warsaw, and all patients provided informed consent.

The Bmode and power Doppler ultrasound of whole thyroid and neck lymph nodes was performed. Six dominant thyroid nodules (in regard to B-mode and power Doppler ultrasound features) were evaluated with shear wave and strain elastography qualitatively and quantitatively as well as some with contrast-enhanced ultrasound (Sonovue (Bracco)). The examinations were performed with following scanner: AiXplorer (Supersonic Imagine Inc. France)—SSWE, Aplio XG (Toshiba, Japan)—strain elastography, Technos (Esaote, Italy)—contrast-enhanced ultrasound, with linear high-resolution transducers: 15–4MHz, 18–7MHz, and, 8–3MHz respectively. For strain elastography, we adopted qualitative scale of Rubaltelli et al. with threshold score of 2/3 and quantitative scale of Cantisani et al. with threshold thyroid tissue/nodule strain ratio of 2 measured with Elasto-Q (Toshiba). For shear wave elastography, we adopted quantitative scale of Sebag et al. with the threshold stiffness (mean elastic modulus) of thyroid nodule of 65 kPa.

The final diagnosis was based on clinical evaluation, multiple FNB, 1 year followup, or surgery.

Discussion

Supersonic shear weave elastography consists of the generation of remote radiation force by focused ultrasonic beams, the so-called “pushing beams,” a patented technology called “Sonic Touch”. Using Sonic Touch, ultrasound beams are successively focused at different depth in tissues. The source is moved at a speed that is higher than the speed of the shear waves that are generated. In this supersonic regime, shear waves are coherently summed in a “Mach cone” shape, which increases their amplitude and improves their propagation distance. For a fixed acoustic power at a given location, Sonic Touch increases shear wave generation efficiency by a factor of 4 to 8 compared to a nonsupersonic source. After generation of this shear wave, an ultrafast echographic imaging sequence is performed to acquire successive raw radiofrequency dots at a very high-frame rate (up to 20,000 frames per second). Based on Young’s modulus formula, the assessment of tissue elasticity can be derived from shear wave propagation speed. A color-coded image is displayed, which shows softer tissue in blue and stiffer tissue in red. Quantitative information is delivered; elasticity is expressed in kilo-Pascal (kPa).

This preliminary paper based on small number of cases indicates that SSWE indicated correctly thyroid nodules suspicious for cancer in contrast to strain elastography. False positives on strain elastography could be due to liquid or degenerative content of nodules.

However, imaging with SSWE, as a sensitive method of evaluation of stiffness of human tissue, the operator should be aware of physiological processes influencing the elasticity and easily apply a few rules to avoid artifacts (Figures 4, 5 and 6). Among well-known artifacts on SSWE that should be mentioned is the one that can be encountered in any region when the SSWE can be applied: the increased stiffness of the structures under externally applied pressure (Figures 4 and 5) that can be due to nonlinear elastic effects, well explained by theory.

Another artifact that can be encountered in thyroid SSWE is one of increased stiffness in the isthmus of the thyroid due to trachea (Figure 6). It can be avoided with imaging in paracoronal plane of the nodule that does not incorporate the trachea. However, it is important to state that these artifacts when properly interpreted do not hinder the accurate diagnosis.

Supersonic shear wave elastography may add a new dimension to ultrasound evaluation of thyroid nodules in several ways, for example:

(a) improve general performance in elasticity differentiation of thyroid nodules over strain elastography due to its high reproducibility, independence of examiners skill and numeral scale of elasticity measurement in kPa;

(b) overcome the limitations of strain elastography=

  (i) nodules with liquid components or with degenerative changes;

  (ii) small nodules (very good spatial resolution of the technique);

  (iii) large nodules (possibility of subsequent determination of stiff regions even  of large nodules, without the need of visualizing the whole nodule on one image);

  (iv) multinodular goiter with no or scarce normal thyroid tissue as a reference;

(c) differentiation between soft-inspissated colloid and stiff microcalcifications;

(d) visualization of microcalcifications, even not visualized on B-mode imaging (may increase sensitivity and decrease specificity of thyroid cancer diagnosis);

(e) introduction of three-dimensional elastographic images to routine clinical practice and to national thyroid cancer databases, as this technique is

already available and enables rapid acquisition of 3D ultrasound and elastographic data. This would devoid diagnostic process and data archiving of image selection bias attributable to 2D ultrasound examination.

Further multicenter large scale studies of thyroid nodules evaluating different elastographic methods are warranted, including (a) investigation of developmental models of diseases that link biomechanical properties (elastography findings) with genetic, cellular, biochemical, and gross pathological changes; (b) comparison of accuracy of different elastographic methods; (c) establishment of optimal diagnostic elastographic criteria; (d) establishment of limitations of different elastographic methods in relation to evaluation of thyroid pathology.

PHÂN BIỆT ÁPXE và VIÊM MÔ TẾ BÀO - ÁPXE LẠNH

Abscess Evaluation

Brian Euerle, MD, RDMS

I. Introduction and Indications

Abscess and cellulitis are two of the most common soft-tissue infections seen in patients treated in emergency departments. Although they sometimes occur together, they are different disease processes requiring different treatments. An abscess is treated with incision and drainage and may not require antibiotics; cellulitis is treated with antibiotics alone.

It can be difficult to differentiate cellulitis from abscess based only on history and physical examination findings. Both processes may generally be characterized by warmth, erythema, tenderness, swelling, and induration. In some patients, an abscess is clearly evident because of obvious fluctuance and copious purulent drainage; however, this distinct presentation is not seen in the majority of cases. Because of the difficulty in diagnosis, the emergency physician might decide upon an inappropriate treatment, resulting in one of two possible errors. Incision and drainage might not be done in a patient with an abscess, or incision and drainage could be performed on a patient who has cellulitis but no abscess. Increased pain and poor patient outcome can result from either one of these errors.

Many researchers, including emergency physicians, have reported on the utility of ultrasound in the evaluation of abscesses and cellulitis. One group of emergency physicians found that soft-tissue ultrasound changed the management strategy for approximately half of their patients and concluded that ultrasound was useful because it could detect occult abscesses and avoid invasive procedures.

Ultrasound also allows many procedures to be done with greater safety. In the case of abscess drainage, ultrasound can locate adjacent structures such as large blood vessels and nerves that need to be avoided during the drainage procedure.

The use of bedside ultrasound can also help determine the treatment of a specific abscess based on its size and depth.
If an abscess is very small (smaller than 1 cm), the physician might choose treatment with antibiotics and warm compresses rather than incision and drainage.

Although the majority of abscesses are treated with incision and drainage, in certain cases, usually because of cosmesis, treatment with needle aspiration and antibiotics may be an option. Ozseker and colleagues found that ultrasound-guided aspiration and irrigation of breast abscesses was preferred to surgical drainage for abscesses with a diameter less than 3 cm. Ultrasound provides dynamic real-time guidance for needle aspiration, resulting in increased success.

II. Anatomy

The structures that are imaged in bedside ultrasound for abscess evaluation are primarily the skin, subcutaneous tissue, and fascia. The skin consists of two layers: the superficial epidermis and the deeper, thicker dermis. Subcutaneous tissue, located beneath the dermis, consists of connective tissue septa and fat lobules. Fascia, a deeper structure, is a dense, fibrous membrane.

III. Scanning Technique, Normal Findings and Common Variants

Equipment
It is important to select an appropriate transducer when using bedside ultrasound for abscess evaluation. Because most subcutaneous abscesses are relatively superficial, a high-frequency (7-12 MHz) linear array transducer is most useful. At times a deeper abscess may be beyond the range of the linear transducer and a lower frequency transducer must be used. In this situation, a lower frequency linear array transducer may be helpful. If this type of transducer is not available, a curvilinear transducer may be used.
Evaluation for peritonsillar abscess is a specialized application in which a high frequency intracavitary probe can be used.

Many emergency practitioners are familiar with the use of color Doppler ultrasound and this can be useful in abscess evaluation. One way in which Doppler can be helpful is by identifying large blood vessels that are adjacent to an abscess. Color Doppler can also be helpful in the evaluation of groin masses because it can help differentiate an abscess from a pseudoaneurysm. Power Doppler is a more advanced technique that is able to detect low velocity blood flow and movement. This can be used in abscess evaluation because it can identify hyperemia in the walls of abscesses and the surrounding tissues.

Scanning Technique

It is helpful to begin scanning a short distance away from the area of interest to gain an appreciation of the appearance of the normal, uninvolved anatomy. It may also be helpful to view the contralateral side of the patient’s body to obtain information about the normal appearance of structures.

Next, slide the probe over the extent of the abscess or cellulitis, maintaining the same orientation. Once the area has been visualized appropriately, rotate the transducer 90 degrees and repeat the process. If an abscess is present, place a gloved finger of the nondominant hand on the point of maximal fluctuance or “point” of the abscess. Then slide the transducer so that its mid-point is located against the finger. This can help you correlate the image on the screen with the anatomy and help plan the site of the incision. Body markings can also be used to indicate the extent of the abscess or location of the incision.

Once the presence of an abscess is confirmed, set the ultrasound probe aside and proceed with the incision and drainage. Another option is to incise the area while observing in real time under ultrasound. This technique may be helpful for deep or small collections, but it generally is not necessary.

It may be helpful to repeat the ultrasound examination after incision and drainage to assess the success of the procedure and locate undrained collections of purulence.

Normal Findings

With the equipment that is typically used for bedside ultrasonography, the epidermis and dermis cannot be differentiated. They appear together as a thin, hyperechoic layer. The subcutaneous layer appears hypoechoic on ultrasound, with two components: hypoechoic fat interspersed with hyperechoic linear echoes running mostly parallel to the skin, which represent connective tissue septa (Figure 1). Veins and nerves may be visualized within the subcutaneous layer.

Fascia appears as a linear hyperechoic layer. Its thickness may vary depending on the location.

Figure 1: Normal skin, subcutaneous tissue, and fascia.

IV. Pathology

On ultrasound an abscess is a spherical or oblong shaped structure that is largely anechoic or hypoechoic (Figure 2). However, as opposed to a simple cyst that will be uniformly anechoic throughout, an abscess will contain hyperechoic debris. This feature can be used to differentiate an abscess from a cyst. The walls of the abscess cavity may be distinct and hyperechoic, or may have a ragged appearance and intermix with the adjacent tissue. Because of the anechoic nature of the abscess, posterior acoustic enhancement may be seen. Dynamic scanning, achieved with gentle compression of the probe, may cause the contents of the abscess to swirl, which can be diagnostic of an abscess. Hyperechoic foci of air may be seen in necrotizing fasciitis.

Figure 2: Abscess containing hyperechoic debris.

The ultrasound appearance of cellulitis may vary depending on the stage and severity. The initial appearance may be generalized swelling and increased echogenicity of the skin and subcutaneous tissues. As cellulitis progresses and the amount of subcutaneous fluid increases, hyperechoic fat lobules become separated by hypechoic fluid-filled areas. This later stage of cellulitis is most typical and has been described as having a cobblestone appearance (Figure 3)

Figure 3: Cobblestone appearance of advanced cellulitis.

V. Pearls and Pitfalls Abscess and cellulitis are two common soft-tissue infections that can appear similar on physical examination. Bedside ultrasound can be very helpful in differentiating cellulitis from abscess. Ultrasound is effective at identifying occult abscesses in emergency department patients initially suspected of having cellulitis. On ultrasound imaging, an abscess appears as a spherical or oblong anechoic or hypoechoic collection containing hyperchoic debris.

Cold Abscess

from www.e-radiography.net

Definition
A cold abscess is an abscess that commonly accompanies tuberculosis. It develops so slowly that there is little inflammation, and it becomes painful only when there is pressure on the surrounding area. This type of abscess may appear anywhere on the body, but it is most commonly found on the spine, hips, lymph nodes, or in the genital region.

Radiographic Appearance
Radiologicaly there may be erosion of bone local to the abscess, or evidence of organ compression.
A sinogram will demonstrate the extent of the abscess.

Plain radiographs occasionally show a blurring or indistinctness of the lateral margins of the psoas muscle but, in general, are not as helpful as other techniques. Ultrasonography is useful in showing enlarged psoas muscle with hypoechogenic masses, however it is not as accurate as a CT scan in showing the abscess. MRI is advantageous because multiple processes can be evaluated.

Pathology
Although primary psoas abscess is very rare in children of "developed" countries, it is not rare in tropic and sub-tropical "third world" countries with poor socioeconomic conditions. Staphylococcus aureus is the most frequent type of infection seen in these environments, with almost all children presenting with the triad of pyrexia, flank pain and hip symptoms.
Psoas abscess can be a secondary problem associated with tuberculous spondylitis or in relation to inflammatory bowel disease (1). More recently, in the United States, psoas abscesses have been seen secondary to transperitoneal low-velocity gunshot wounds to the spine (3), or gastrointestinal or genitourinary trauma (2). Primary psoas abscess can be seen in patients with sickle cell disease, intravenous drug users, immunocompromised individuals or individuals positive for HIV.

Treatment:
Drainage of the abscess by CT-guided percutaneous catheter has been recommended by some, while surgical drainage is recommended by others, especially when percutaneous catheter drainage is not successful, followed by appropriate antibiotic therapy.

NHÂN CA CYSTIC LYMPHANGIOMA CỦA ĐUÔI TUỴ TẠI MEDIC

Xem HUGE CYSTIC LYMPHANGIOMA of PANCREAS tại MEDIC.

Discussion of Pancreatic Lymphangioma

from http://www.tmuh.org.tw
Background

- Neoplasms, hamartomas, or lymphangiectasias ?

- Malformations arising from sequestered lymphatic channels

or

- Acquired lesions due to obstruction caused by fibrosis of lymph channels.

- Developmental anomaly, distension of sequestered lymphatic channels within primitive mesenchyme rather than a true neoplasm.

- Most common sites: head, neck, and axilla.

- Only 5 % at mesentery, omentum, mesocolon, and retroperitoneum.

- Pancreatic lymphangiomas (1%) occur predominantly in women (F/M: 2:1). Average age : 25.6 years.

Classification

- Cystic, capillary, and cavernous.

- Only cystic and cavernous types have been reported in the pancreas

- Considered to be of pancreatic origin :

• in the pancreatic parenchyma,
• adjacent to the pancreas,
• connected to the organ by a pedicle

Clinical Presentations

- Abdominal pain

- Nausea

- Vomiting

- Palpable mass

- Silent, incidental finding.

Morbidity/ Mortality

- No risk of malignant transformation.

- May local invasion.

- Strong tendency for local recurrence unless they are completely excised.

Pathology 

Gross

- Soft, multiloculated cystic masses.

- Content: serous, serosanguinous, or lymphatic fluid.

Histology

- Dilated lymphatic channels, separated by thin septa.

- Cystic spaces lining:  flattened or cuboidal endothelial cells.

- Aggregates of lymphocytes.

- The septa and walls: smooth muscle fascicles and collagenous connective

tissue.

Image -- Sonography character

- Anechoic or hypoechoic

- Fluid-filled

- Multiseptated mass in the pancreatic region.

Image -- CT character

- Well-circumscribed

- Homogeneous cystic masses in or adjacent to the pancreas.

- Septums and thin walls may enhance after IV contrast injection.

Image -- MRI character

- Hypointense on T1-weighted image

- Hyperintense on T2-weighted image.

- Not provide new information.

Diagnosis

- History

- Imaging: sono, CT, MRI

- Fine-needle aspiration cytology.

- Definite diagnosis: pathology report.

Treatment

- No proven medical care for lymphangiomas exists.

- Treatment of choice: complete surgical excision.

Prognosis

- Lymphangiomas are benign hamartomatous malformations instead of true neoplasms.

- Locally invasion may occur.

- The prognosis is excellent.

NHÂN CA NANG GIẢ TỤY TẠI MEDIC

Ultrasonography

On US examination, pancreatic pseudocysts appear as anechoic structures associated with acoustic enhancement, as demonstrated in the images below. Pseudocysts are well defined and round or oval, and they are contained within a smooth wall.

Intraoperative sonogram of a pancreatic pseudocyst.

Intraoperative sonogram demonstrates internal echoes in pancreatic pseudocyst fluid. This finding suggests presence of necrotic debris or possible pus.

An intraoperative sonogram is used to guide needle placement through the posterior wall of the stomach and into a pancreatic pseudocyst. Fluid is aspirated to delineate placement of the cystgastrostomy site and to sample the fluid within. The needle is clearly depicted as the bright echogenic line entering the fluid-filled cavity.

During the early phases of their development, pseudocysts can appear more complex, with varying degrees of internal echoes. Usually, this appearance results from the presence of necrotic pancreatic and peripancreatic debris and is more common in pseudocysts that form as a result of acute necrotizing pancreatitis than in other pseudocysts. The debris is cleared over time. The pseudocyst can appear more complex in 2 other instances: when hemorrhage occurs into the cyst or when infection of the cyst complicates the clinical course.

Color Doppler or duplex scanning should always be performed in cystic lesions to ensure that the lesion in question is not a giant pseudoaneurysm.

Degree of confidence

Sensitivity rates for US in the detection of pancreatic pseudocysts are 75-90%, according to Pitchumoni and Agarwal; therefore, US is slightly inferior to CT, which, as previously mentioned, has a sensitivity of 90-100%.^[11]

US has several limitations, as compared with CT, in the initial diagnosis of a pseudocyst: the presence of overlying bowel gas decreases the sensitivity of US, and unlike CT, US examinations are highly operator dependent. However, CT scans provide more information regarding the surrounding viscera and vasculature.

False positives/negatives

No normal anatomic variants mimic the presence of a pseudocyst; however, other cystic pancreatic masses can be misinterpreted as pseudocysts. This observation is important, because as many as 10% of cystic pancreatic lesions are neoplasms; examples of these include serous and mucinous cystadenomas and mucinous cystadenocarcinomas. Clues to the diagnosis of a neoplastic cyst include a complex nature and the presence of internal septations, which can be extremely difficult to detect with US.

Brugge states that endoscopic US is helpful in the differentiation of pancreatic fluid collections.^[12] Endoscopic US is more sensitive than transcutaneous US for demonstrating the internal architecture of the lesions.