Primary neoplasms of peritoneal and sub-peritoneal origin: CT findings

Mimics of primary ovarian cancer and primary peritoneal carcinomatosis - A pictorial review

Numerous conditions can mimic ovarian malignancy. Identifying the origin of a pelvic mass or disseminated peritoneal abnormality on imaging is important to ensure that the patient receives optimal management by the appropriate clinical team. Ovarian cancer mimics include infections and other neoplastic processes, for example, actinomycosis, lymphoma, and sarcoma. We will illustrate intraperitoneal and extraperitoneal ovarian and non-ovarian mimics. Primary peritoneal carcinomatosis mimics include processes such as deep infiltrating endometriosis and rare causes such as gliomatosis peritonei and diffuse peritoneal leiomyomatosis. We aim to illustrate the multimodality key imaging appearances of common and rarer types of mimics.

Ibero-American Consensus for the Management of Peritoneal Sarcomatosis: Updated Review and Clinical Recommendations

Peritoneal sarcomatosis is a rare malignant disease with a poor prognosis, secondary to peritoneal dissemination of abdominopelvic soft tissue sarcomas. Its rarity, together with the characteristic histological heterogeneity and the historically poor response to systemic treatments, has prevented the establishment of widely accepted treatment criteria with curative intent. In this sense, radical cytoreductive surgery (CRS) with peritonectomy procedures and hyperthermic intraperitoneal chemotherapy (HIPEC), widely used in peritoneal carcinomatosis with excellent results, have not had the same evolutionary development in patients with peritoneal sarcomatosis. A multidisciplinary working group of experts in sarcomas and peritoneal oncological surgery established a series of recommendations based on current scientific evidence for the management of peritoneal sarcomatosis, taking into account the different histological subgroups of abdominopelvic sarcomas that can cause it depending on their origin: retroperitoneal sarcomas, uterine sarcomas, and visceral/peritoneal sarcomas of GIST (gastrointestinal stromal tumor) and non-GIST origin. This article shows the results of sarcoma experts' voting on the recommendations presented during the I Ibero-American Consensus on the Management of Peritoneal Sarcomatosis, which took place during the recent celebration of the III Hispanic-Portuguese Meeting for Updates on the Treatment of Sarcomas.

Navigating the labyrinth of peritoneal and extraperitoneal anatomy: abdominal spread made easy with a case based review

Essential to understanding disease spread in abdomen is to separate the peritoneum from the extraperitoneum. These areas have distinct anatomy with well-define separate pathways. The peritoneum is comprised of connected recesses that are potential spaces, normally not imaged except when containing excess fluid or air. Peritoneal recesses are formed by the opposing peritoneal surfaces and subdivided by the attachments of the ligaments and mesenteries to the parietal peritoneum. Disease flows within the recesses by changes in abdominal pressure. This forms a distinct spread pattern. The extraperitoneum is traditionally stratified by the renal fascia into the anterior and posterior pararenal spaces and the perirenal space. The fascia contains and directs spread from the contained organs with the compartments. Each space has a unique spread pattern defined by the containing fascia. The extraperitoneum is connected to the mesenteries and ligaments forming the subperitoneal space. This space interconnects the extraperitoneum with the mesenteries allowing for the normal continuum of blood vessels, lymphatics, and nerves but also forms the pathways for bidirectional spread of disease.

Peritoneal Carcinosis: What the Radiologist Needs to Know

Peritoneal carcinosis is a condition characterized by the spread of cancer cells to the peritoneum, which is the thin membrane that lines the abdominal cavity. It is a serious condition that can result from many different types of cancer, including ovarian, colon, stomach, pancreatic, and appendix cancer. The diagnosis and quantification of lesions in peritoneal carcinosis are critical in the management of patients with the condition, and imaging plays a central role in this process. Radiologists play a vital role in the multidisciplinary management of patients with peritoneal carcinosis. They need to have a thorough understanding of the pathophysiology of the condition, the underlying neoplasms, and the typical imaging findings. In addition, they need to be aware of the differential diagnoses and the advantages and disadvantages of the various imaging methods available. Imaging plays a central role in the diagnosis and quantification of lesions, and radiologists play a critical role in this process. Ultrasound, computed tomography, magnetic resonance, and PET/CT scans are used to diagnose peritoneal carcinosis. Each imaging procedure has advantages and disadvantages, and particular imaging techniques are recommended based on patient conditions. Our aim is to provide knowledge to radiologists regarding appropriate techniques, imaging findings, differential diagnoses, and treatment options. With the advent of AI in oncology, the future of precision medicine appears promising, and the interconnection between structured reporting and AI is likely to improve diagnostic accuracy and treatment outcomes for patients with peritoneal carcinosis.

Imaging of pediatric abdominal soft tissue tumors: A COG Diagnostic Imaging Committee/SPR Oncology Committee White Paper

This paper provides imaging recommendations for pediatric abdominal tumors that arise outside of the solid viscera. These tumors are rare in children and have been categorized in two groups: abdominal wall and peritoneal tumors (desmoid tumor and desmoplastic small round cell tumor) and tumors that arise from the gastrointestinal tract (gastrointestinal stromal tumor and gastrointestinal neuroendocrine tumor). Authors offer consensus recommendations for imaging assessment of these tumors at diagnosis, during follow-up, and when off-therapy.

[Radiologic Evaluation of Uterine Lesions Using a Pattern Recognition Approach]

It is important to distinguish uterine lesions from other lesions occurring in the pelvic cavity for the proper management. The primary radiological evaluation of uterine lesions is performed using transvaginal ultrasonography, and if the lesion is too large or shows atypical benign imaging findings, magnetic resonance imaging should be performed. Analyzing radiological findings of uterine lesions through a pattern recognition approach can help establish the accurate diagnosis and treatment plan. In this pictorial assay, we describe imaging characteristics of various lesions arising from the uterus and evaluate them based on the pattern recognition approach.

Is MDCT an accurate tool to differentiate between benign and malignant etiology in diffuse peritoneal disease?

PURPOSE

There is often considerable overlap of imaging findings in benign and malignant peritoneal diseases. We evaluated patients with diffuse peritoneal disease, to assess the diagnostic value of MDCT in predicting benign or malignant etiology in patients with unknown etiology, by analyzing the various patterns of involvement, particularly tuberculosis (TB) vs malignancy.

METHODS

One hundred and thirty-six patients with diffuse peritoneal disease who had abdominal CT and subsequently underwent omental biopsies were included in the study. Peritoneal, mesenteric and omental involvement by disease was evaluated on CT using specific parameters. The presence of lymphadenopathy, ascites, scalloping of organs, involvement of liver and spleen, were also compared between benign and malignant conditions using histopathology as the gold standard.

RESULTS

In 136 patients, 72 benign and 64 malignant pathologies were classified as per histopathology. Higher age (p < 0.001), increasing omental thickness (mean 25.2 mm, p = 0.004), omental caking (p < 0.001), > 10 mm mesenteric/peritoneal nodules (p < 0.03), visceral scalloping (p = 0.001), free ascites (p = 0.003), serosal involvement (p = 0.004) and bilateral pleural effusion (p = 0.02) were associated with malignant etiology. Mesenteric thickening/stranding (p = 0.02), mesenteric adenopathy (p < 0.001), necrotic nodes (p = 0.02), splenomegaly (p =  < 0.001) and higher attenuation (> 20HU) of ascitic fluid (p < 0.001) were associated with benign etiology. The presence of mesenteric thickening or stranding (p = 0.01), splenomegaly (p = 0.02), higher ascitic fluid attenuation > 20HU (p =  < 0.01), mesenteric adenopathy (p < 0.01), necrotic nodes (p = 0.03) favored tuberculosis. CT had diagnostic accuracy (79.3, 86.7%), sensitivity (79.2, 74.6%) and specificity (79.4, 97%) for observers 1 and 2, respectively (Kappa 0.713).

CONCLUSION

Contrast-enhanced MDCT has good sensitivity, specificity and accuracy in differentiating benign and malignant etiologies of diffuse peritoneal disease. Multiple common parameters can be used to differentiate between tuberculous peritonitis and peritoneal carcinomatosis.

Radiology of the Mesentery

The recent description and re-classification of the mesentery as an organ prompted renewed interest in its role in physiological and pathological processes. With an improved understanding of its anatomy, accurately and reliably assessing the mesentery with non-invasive radiological investigation becomes more feasible. Multi-detector computed tomography is the main radiological modality employed to assess the mesentery due to its speed, widespread availability, and diagnostic accuracy. Pathologies affecting the mesentery can be classified as primary or secondary mesenteropathies. Primary mesenteropathies originate in the mesentery and subsequently progress to involve other organ systems (e.g., mesenteric ischemia or mesenteric volvulus). Secondary mesenteropathies describe disease processes that originate elsewhere and progress to involve the mesentery with varying degrees of severity (e.g., lymphoma). The implementation of standardized radiological imaging protocols, nomenclature, and reporting format with regard to the mesentery will be essential in improving the assessment of mesenteric anatomy and various mesenteropathies. In this article, we describe and illustrate the current state of art in respect of the radiological assessment of the mesentery.

The role of imaging in diagnosis and management of malignant peritoneal mesothelioma: a systematic review

PURPOSE

Imaging of the peritoneum and related pathology is a challenge. Among peritoneal diseases, malignant peritoneal mesothelioma (MPeM) is an uncommon tumor with poor prognosis. To date, there are no specific guidelines or imaging protocols dedicated for the peritoneum and MPeM. The objective of this study was to analyze the literature describing imaging modalities used for MPeM to determine their relative clinical efficacy and review commonly reported imaging features of MPeM to promote standardized reporting.

METHODS

We performed a systematic review of original research articles discussing imaging modalities in MPeM from 1999 to 2020. Effectiveness measures and common findings were compared across imaging modalities.

RESULTS

Among 582 studies analyzed, the most-used imaging modality was CT (54.3%). In the differentiation of MPeM from peritoneal carcinomatosis, one study found CT had a diagnostic sensitivity of 53%, specificity of 100%, and accuracy of 68%. Two studies found fluorodeoxyglucose positron emission tomography (FDG-PET) had sensitivity of 86-92%, specificity of 83-89%, and accuracy of 87-89%. Another study found magnetic resonance imaging (MRI) was the best predictor of the peritoneal carcinomatosis index. Characteristics shown to best differentiate MPeM from other diseases included ascites, peritoneal thickening, mesenteric thickening, pleural plaques, maximum tumor dimension, and number of masses.

CONCLUSION

Most published MPeM imaging studies utilized CT. PET/CT or MRI appear promising, and future studies should compare effectiveness of these modalities. MPeM imaging reports should highlight ascites, number of and maximum tumor dimension, peritoneal/mesenteric thickening, and associated pleural plaques, allowing for better aggregation of MPeM imaging data across studies.

Primary malignant peritoneal mesothelioma mimicking tuberculous peritonitis: A case report

BACKGROUND

Malignant peritoneal mesothelioma (MPM) is a rare malignancy arising in mesothelial cells in the peritoneum. It can be mistaken for many other diseases, such as peritoneal carcinomatosis and tuberculous peritonitis (TBP), because its clinical manifestations are often nonspecific. Therefore, the diagnosis of MPM is often challenging and delayed.

CASE SUMMARY

A 42-year-old man was referred to our hospital with lower abdominal pain for 1 wk and ascites observed under abdominal sonography. His laboratory findings revealed an isolated elevated tumor marker of carcinoma antigen 125 (167.4 U/mL; normal, < 35 U/mL), and contrast enhanced computed tomography showed peritoneal thickening. Thus, differential diagnoses of TBP, carcinomatosis of an unknown nature, and primary peritoneal malignancy were considered. After both esophagogastroduodenoscopy and colonoscopy produced negative findings, laparoscopic intervention was performed. The histopathological results revealed mesothelioma invasion into soft tissue composed of a papillary, tubular, single-cell arrangement of epithelioid cells. In addition, immunohistochemical staining was positive for mesothelioma markers and negative for adenocarcinoma markers. Based on the above findings, TBP was excluded, and the patient was diagnosed with MPM.

CONCLUSION

It is important to distinguish MPM from TBP because they have similar symptoms and blood test findings.

Fat-containing pelvic lesions in females

Pelvic tumors are common in females and have a broad differential diagnosis. The clinical management of pelvic tumors varies widely-from observation to surgical resection-and imaging plays a pivotal role in diagnosis and clinical decision-making in these cases. In particular, imaging can help determine the organ of origin and tissue content of these tumors, which are the most important steps to narrowing the differential diagnosis. Fat has a characteristic appearance and is often easily identified on ultrasonography (US), computed tomography (CT), and magnetic resonance imaging (MRI). The amount and distribution of intralesional fat varies in different types of tumors. Macroscopic intralesional fat is often easily recognized by its hyperechoic appearance on US and low attenuation on CT similar to subcutaneous fat. On MRI, macroscopic fat is hyperintense on T1-weighted (T1W) images, with characteristic signal loss on fat-saturated sequences and India-ink artifact on opposed-phase T1W images. Macroscopic fat is the hallmark of teratomas, which are the most common ovarian neoplasms. Uterine lipoleiomyomas, peritoneal loose bodies, intraperitoneal and extraperitoneal primary lipomatous tumors such as lipoma and liposarcomas, and extra-adrenal myelolipomas are other pelvic masses distinguished by the presence of macroscopic fat. However, the imaging diagnosis of pelvic masses containing minimal or microscopic fat, such as immature ovarian teratomas, steroid cell ovarian neoplasms, and extramedullary hematopoiesis, can present a diagnostic challenge owing to their nonspecific appearance on US or CT. Obtaining MRI with in-phase and opposed-phase dual-echo T1W sequences and depicting chemical shift artifacts can be helpful in distinguishing these lesions.

The role of cytology as an effective tool in management of omental and peritoneal lesions: Experience of a large health care system

BACKGROUND

The aim of this study is to assess the efficacy of cytology in omental or peritoneal lesions.

METHODS

A retrospective review of the pathology database for cytology cases of peritoneal or omental nodules over a 3-year period (2016-2018) was conducted. The cases consisted of either FNA only (FO); FNA and Core biopsy (FCB) or Touch prep and core biopsy (TCB). Cases were further divided based on the prior history of carcinoma. Concordance rates of cytologic diagnosis with histologic diagnosis were studied.

RESULTS

Out of 104 cytology cases reviewed, 60 (57.7%) had prior history of cancer (PHC) and 44 (42.3%) had no prior history of cancer (NPHC). Of the cases with PHC, 43(71.66%) were recurrence, 10 (16.66%) were second cancer, and 7 (11.66%) were non-neoplastic lesions. Of the cases with NPHC, 38 (86.4%) had a second cancer diagnosis, while 6 (13.6%) were non-neoplastic. For FO only cases, 11 of 35 (31.4%) had follow up and 9 of 11 (81.8%) were concordant. For FCB cases, 6 out of 39 (15.4%) had follow up and 6 (100%) were concordant. For TCB cases, 9 out of 30 (30%) had follow up and 9 (100%) were concordant. A definite diagnosis was reached in 30/35, 39/39, and 29/30 cases in FO, FCB, and TCB, respectively.

CONCLUSION

In summary, cytologic evaluation of omental lesions is an effective tool in providing accurate diagnosis and guiding further management. Also, the results based on our study show that the combined techniques are superior at reaching a definitive diagnosis.

Ultrasound-Guided Omental Biopsy: Diagnostic Yield and Association With CT Features Based on a Single-Institution 18-Year Series

BACKGROUND. The greater omentum can serve as a useful target for percutaneous biopsy; in clinical practice, CT is commonly used for biopsy guidance. OBJECTIVE. The purpose of this study was to evaluate the diagnostic yield of percutaneous ultrasound (US)-guided omental biopsy and to explore the association of the diagnostic yield with prebiopsy diagnostic CT findings. METHODS. This retrospective study included 163 patients (120 women and 43 men; mean age, 65 ± 12 [SD] years; mean body mass index [BMI], 28.9 ± 7.9) who underwent US-guided omental biopsy between 2002 and 2020 at a single institution at which US served as the first-line modality for omental biopsy guidance. Biopsies were performed by abdominal radiologists without dedicated interventional radiology fellowship training. Postbiopsy clinical follow-up and imaging follow-up were reviewed to establish the ultimate diagnosis for each patient. Omental biopsies were characterized as diagnostic or nondiagnostic relative to the ultimate diagnosis. Associations were explored between diagnostic yield and findings on prebiopsy CT and biopsy US. RESULTS. US-guided omental biopsy was performed using an 18-gauge core needle biopsy technique in 156 patients and fine-needle aspiration in seven patients. The mean number of biopsy passes was 2.5 ± 1.0, and mean omental thickness near the biopsy site on CT was 2.6 ± 1.2 cm. On prebiopsy diagnostic CT, omental disease appeared infiltrative in 127 (78%) patients versus mass-forming in 36 (22%) and appeared hypoechoic in 105 (64%) patients versus iso- to hyperechoic in 58 (36%). The ultimate diagnosis was malignant tumor in 154 (95%) patients (most commonly, gynecologic tumors in 82 patients [high-grade serous adenocarcinoma in 56] and gastrointestinal tumors in 45 patients) and a benign finding in nine (6%) patients. The omental biopsy was diagnostic relative to the ultimate diagnosis in 155 (95%) patients. A diagnostic versus nondiagnostic biopsy was not associated (p > .05) with age, BMI, number of biopsy passes, or omental target thickness or attenuation. A total of 94% (120/127) of US-guided omental biopsies of infiltrative cases and 97% (35/36) of biopsies of mass-forming cases were diagnostic (p = .50). A total of 96% (102/106) of US-guided omental biopsies of hypoechoic cases and 93% (53/57) of biopsies of iso- to hyperechoic cases were diagnostic (p = .36). No complications occurred. CONCLUSION. US-guided biopsy of omental disease suspected on CT is safe and effective for tissue diagnosis. Although omental disease commonly appears on US as diffuse infiltrative thickening without a discrete target, sampling based on prebiopsy CT landmarks is diagnostic in most cases. CLINICAL IMPACT. US should be considered the first-line modality for omental biopsy guidance when feasible.

[Imaging of Mesentery and Omentum]

Although primary tumors in the mesentery and omentum are relatively rare, it is often necessary to distinguish them from other non-tumorous diseases. Since the omentum and mesentery are major routes for the spread of various abdominal diseases, the anatomy, type, and pattern of the diseases affecting these organs should be known in detail for accurate differential diagnosis. In addition, it is important to detect and promptly treat hidden lesions in the mesentery and omentum. Therefore, careful observation of the area where the lesion occur should be emphasized when assessing mesentery and omentum in abdominal CT.

CT imaging review of uncommon peritoneal-based neoplasms: beyond carcinomatosis

Pathologic involvement of the peritoneum can result from a wide variety of conditions, including both neoplastic and non-neoplastic entities. Neoplastic involvement of the peritoneal ligaments, mesenteries, and spaces from malignant spread of epithelial cancers, termed peritoneal carcinomatosis, is frequently encountered at CT evaluation. However, a host of other more unusual benign and malignant neoplasms can manifest with peritoneal disease, including both primary and secondary peritoneal processes, many of which can closely mimic peritoneal carcinomatosis at CT. In this review, we discuss a wide array of unusual peritoneal-based neoplasms that can resemble the more common peritoneal carcinomatosis. Beyond reviewing the salient features for each of these entities, particular emphasis is placed on any specific clinical and CT imaging clues that may allow the interpreting radiologist to appropriately narrow the differential diagnosis and, in some cases, make an imaging-specific diagnosis.

The Peritoneum: What Nuclear Radiologists Need to Know

The peritoneum is the largest and most complex serous membrane in the human body. The peritoneal membrane is composed of a layer of mesothelium supported by a thin layer of connective tissue. The peritoneum is one continuous sheet, forming two layers and a potential space between them - the peritoneal cavity- which is subdivided into multiple communicating spaces containing small amount of serous fluid that facilitates frictionless movement of mobile intraabdominal viscera. Peritoneum also contributes to fluid exchange mechanism and plays a role in immune response. The peritoneum is subject to many neoplastic and non-neoplastic processes including infections, trauma, developmental and inflammatory processes. Different Nuclear Medicine imaging techniques can be used to diagnose peritoneal diseases, most of these techniques can be customized depending on the clinical scenario and expected findings. Peritoneal scintigraphy can detect abnormal peritoneal communication or compartmentalization. Several nuclear medicine techniques can help characterize intraperitoneal fluid collections and differentiate sterile from infected fluid. PET imaging plays an important role in imaging of different neoplastic and non-neoplastic peritoneal pathologies. Nuclear radiologists need to be familiar with peritoneal anatomy and pathology to interpret peritoneal findings in dedicated peritoneal nuclear medicine imaging studies, as part of more general nuclear medicine scans, or on CT or MRI component of hybrid imaging studies. The purpose of this article is to review the normal peritoneal anatomy, various pathologic processes involving the peritoneum, and different nuclear medicine and hybrid imaging techniques that can help detect, characterize, and follow up peritoneal pathology.

Non-neoplastic conditions mimicking peritoneal carcinomatosis at CT imaging

The general appearance of peritoneal carcinomatosis at abdominal CT and other cross-sectional imaging modalities consists of varying amounts of peritoneal-based soft tissue implants (mass-forming or infiltrative), peritoneal fluid, and occasionally calcification. However, a wide variety of common and uncommon neoplastic and non-neoplastic conditions can closely mimic peritoneal carcinomatosis at imaging. Neoplastic mimics of peritoneal carcinomatosis include primary peritoneal and sub peritoneal tumors, as well as peritoneal lymphomatosis and sarcomatosis.Broad categories of non-neoplastic mimics of peritoneal carcinomatosis include tumor-like conditions, systemic processes, atypical infections, and fat-based conditions. For many entities, suggestive or specific patient information and/or CT imaging findings exist that may allow the radiologist to narrow the differential diagnosis. In this article, we review the salient clinical and cross-sectional imaging features of non-neoplastic mimics of peritoneal carcinomatosis and malignancy, with emphasis on the CT findings and the additional clues that may suggest the correct benign diagnosis.

Desmoplastic Small Round Cell Tumor: Imaging Pattern of Disease at Presentation

OBJECTIVE

The purpose of this study is to evaluate the clinical, pathologic, and multimodality cross-sectional imaging features of a cohort of 94 patients with desmoplastic small round cell tumor (DSRCT).

MATERIALS AND METHODS

This retrospective study of 94 patients with pathologically verified DSRCT was conducted at a tertiary cancer center between 2001 and 2013. Epidemiologic, clinical, pathologic, and imaging findings were recorded. Tumor size, location, and shape and the distribution pattern of metastases at presentation were analyzed.

RESULTS

DSRCT most often occurred in young patients (median age, 21.5 years; range, 5-53 years), showing a marked predominance in male patients (86 male patients vs eight female patients). Eighty nine-patients (95%) were white (defined in this study as white or Hispanic), four were African American, and one was of Asian descent. Most patients had symptoms, with abdominal pain noted as the most common symptom. At initial presentation, 85 patients (90%) had multifocal disease, nodular disease, diffuse omental and peritoneal disease, or a combination of these conditions. Thirty-eight patients (40%) had diaphragmatic involvement. Thirty-two patients (34%) had liver metastases, and 49 patients (52%) had retroperitoneal involvement in the form of implants, tumoral extension, or nodal involvement. With regard to thoracic findings, 33 patients (35%) had nodal disease, 17 (18%) had pleural effusions, and only two (2%) had lung metastases at presentation. Twelve patients (13%) had calcified lesions.

CONCLUSION

DSRCT is a rare, multifocal peritoneal malignancy with frequently disseminated abdominal disease at presentation. In the abdomen, disease most commonly involves the omentum and peritoneum, followed by the retroperitoneum. The liver is the most common solid visceral metastatic site. A substantial number of patients have diaphragmatic involvement. In the thorax, nodal and pleural involvement is more common than lung involvement.

Computed tomographic features of abdominal tuberculosis: unmask the impersonator!

PURPOSE

Abdominal tuberculosis (ATB) mimics various infectious, inflammatory, and neoplastic conditions and hence requires a high index of suspicion for accurate diagnosis, especially in low prevalence areas. It is difficult to consistently establish a histopathological diagnosis of ATB which underlines the importance of supportive evidences for institution of prompt empirical therapy to prevent associated morbidity and mortality.

METHODS

We retrospectively evaluated clinical and imaging features of 105 ATB cases and classified their CT findings based on peritoneal, lymph node, bowel, and solid organ involvement. Concomitant pulmonary and extra-pulmonary involvement was assessed.

RESULTS

Abdominal pain (78.1%) followed by fever (42.9%) were the commonest presenting symptoms. Peritoneal TB (77.14%) most commonly presented with a mix of ascites (49.38%), peritoneal (28.40%), and omental involvement (27.16%). Lymphadenopathy (57.1%) most commonly presented as necrotic nodes (81.67%) at mesenteric, peripancreatic, periportal, and upper paraaortic regions. Commonest site of bowel involvement (cumulative of 62.85%) was ileocecal region, with the commonest pattern of involvement being circumferential bowel wall thickening without bowel stratification with mild luminal narrowing. Hepatic (13.33%) and splenic (16.2%) involvement predominantly presented as multiple microabscesses. Adrenal and pancreatic involvement was noted in 4.7% and 1.9% of patients, respectively. 38.1% patients showed concomitant pulmonary and extra-pulmonary TB.

CONCLUSION

ATB has varied radiological features; however, peritoneal involvement in the form of mild ascites, smooth peritoneal thickening, smudgy omentum, multi-focal bowel involvement, necrotic nodes, and multiple visceral microabscesses point towards a diagnosis of ATB in appropriate clinical setting.

Uncommon Imaging Findings of Inflammatory Myofibroblastic Tumor: Report of a Rare Case With Both Omentum and Mesentery Involvement in the Abdominal Cavity

The inflammatory myofibroblastic tumor (IMT) is a rare stromal tumor with diverse imaging findings. The present study describes a case of contrast-enhanced CT and F-FDG PET/CT manifestations of an IMT with diffuse omental and mesenteric thickening and swelling in the entire abdominal cavity. It is extremely rare to observe such imaging features in the extrapulmonary IMT. Furthermore, this case emphasizes that F-FDG PET/CT holds the potential for demonstrating IMT lesion extent and correctly identifying appropriate sites for biopsy.

Intra-abdominal necrotic lipoma diagnosed by computed tomography as a paraprostatic cyst

A dog with a history of diarrhea and dyschezia exhibited an oval-shaped, soft-tissue opacity mass in the abdomen on radiographs. CT examination revealed a large fluid-filled structure displacing the urinary bladder, prostate, and colon. The mass had continuity with the prostate; therefore, it was tentatively diagnosed as a paraprostatic cyst. Cytologic examination was performed and the mass was considered a non-inflammatory cyst. However, after surgery, histopathologic examination revealed a necrotic, inflamed cystic lipoma. This case shows that unusual intra-abdominal lipomas may have a cystic appearance.

[Borderline and malignant mesenchymal tumors of the abdomen]

BACKGROUND

Soft tissue sarcomas are most common mesenchymal malignancies in the abdomen. Their radiologic features are often unspecific and establishing a differential diagnosis to other pathologies can be difficult.

OBJECTIVES

This review presents a selection of the most common mesenchymal abdominal tumors and their imaging characteristics, as well as the associated differential diagnoses. Knowledge of fundamental pathologic, anatomic and radiologic features of these malignancies is crucial for the differential diagnosis and key in clinical decision making and subsequent selection of an appropriate therapeutic regimen.

A case of malignant peritoneal mesothelioma suggesting the utility of combining double-contrast radiography and endoscopy with computed tomography for diagnosis

A 68-year-old woman presented with abdominal pain, weight loss, and vomiting. Enhanced computed tomography (CT) showed slightly increased density in the mesentery and edema of the third portion of the duodenum and proximal jejunum. Little ascites, but no primary lesion, lymph node metastases, or distant metastases, were observed. Endoscopic findings included erythema and edema in the distal duodenum and proximal jejunum without epithelial lesions. Double-contrast radiography revealed transverse ridging with convergence, suggesting a serosal lesion. We suspected disease involving the serosa, such as mesenteric panniculitis. However, the lesion was definitively diagnosed as malignant peritoneal mesothelioma based on a biopsy specimen obtained at laparotomy. The combination of transverse ridging with convergence on double-contrast radiography and mucosal edema without epithelial lesions on endoscopy was consistent with a disorder involving the serosa. Transverse ridging with convergence is helpful to diagnose serosal pathology such as malignant peritoneal mesothelioma. Combining the findings of double-contrast radiography and endoscopy with computed tomography may facilitate diagnosis of malignant peritoneal mesothelioma. Thus, in case of increased density of mesentery and wall thickness on CT image with transverse ridging with convergence on double-contrast radiography and without epithelial lesion on endoscopy, malignant peritoneal mesothelioma must be considered.

Detection and management of retroperitoneal cystic lesions: A case report and review of the literature

The identification of cystic lesions within the retroperitoneal space is a rare event that poses clinicians the challenge of a difficult diagnosis and disease management. Retroperitoneal cystic lesions account for a group of lesions that range from common benign lesions (e.g., lymphoceles developing as a surgical complication) to rare aggressive malignant neoplasms. Currently, in the majority of cases, image-guided procedures allow for a pathological diagnosis to be achieved in these challenging lesions, thus offering the chance of an appropriate treatment; however, the overall clinical assessment of retroperitoneal cysts is highly demanding. The present study reports the management of a representative clinical case, presenting with a voluminous cystic mass able to dislocate cave vein, whose diagnosis was preceded by a deep vein thrombosis. Computed tomography-scan and ultrasound guided percutaneous drainage were performed to achieve the diagnosis. Following the discussion of the current case report, a review of the pathological and radiological characteristics of retroperitoneal cystic lesions is presented.

Case Report of Four Different Primary Mesenteric Neoplasms and Review of Literature

INTRODUCTION

It is rare for primary tumors to arise from the mesentery. Lymphangiomas appear as congenital malformations of the lymphatic system or benign neoplasms as a large, thin-walled, often multilocular cyst. Mesenteric infiltration is common and during surgical treatment, adjustment of structures such as the bowel and resection of the spleen may be required. Cystic mesotheliomas are rare, benign tumors that originate from the peritoneal mesothelium and are more common in women. Mesenteric cysts are mostly benign and rare intra-abdominal tumors, and can be seen as occupying a large cyst. Malignant fibrous histiocytoma is a rare pleomorphic sarcoma that is more commonly encountered in men. After the extremities, the second most common areas to be affected are the retroperitoneum and peritoneal cavity.

CASE PRESENTATION

We encountered four cases of different primary mesenteric neoplasms that were operated at the Gazi Yasargil teaching and research hospital, department of general surgery, Diyarbakir, Turkey, between 2013 and 2014. We reviewed these primary mesenteric neoplasms and compared them with previous literature.

CONCLUSIONS

Primary mesenteric tumors are rare and mostly benign tumors. Complete surgical excision is necessary for all tumors and follow-up is necessary after surgery for malignant fibrous histiocytoma due to recurrence.

A case of lipoma of parietal peritoneum causing abdominal pain

Lipomas are common benign tumors of mature adipose tissue, enclosed by thin fibrous capsules. They can occur on any part of the body; however, peritoneal lipoma is extremely rare. We encountered a case of a 75-year-old man presenting with intermittent abdominal pain, who had undergone right hemicolectomy due to colon cancer. Abdominal computerized tomography showed a well-defined heterogenous fatty mass measuring 4.5 × 3.5 cm in size, suggesting fat necrosis located in the abdominal wall. Laparotomy showed a very large soft mass of peritoneum. Pathologically, the tumor was diagnosed as lipoma containing fat necrosis located in parietal peritoneum not fixed to any organs, but with small bowel adhesion. Due to its rare etiologic origin and obscure cause of development, we report on a case of lipoma of parietal peritoneum causing abdominal pain.

Primary Peritoneal Mesothelioma Resulting in Small Bowel Obstruction: A Case Report and Review of Literature

BACKGROUND

Peritoneal mesothelioma is a rare malignancy that affects the serosal surfaces of the peritoneum. The peritoneum is the second most common site of mesothelium affected following the pleura. The aggressive nature and vague presentation pose many obstacles in not only diagnosis but also the treatment of patients with this disease.

CASE REPORT

We present a case of a 76-year-old woman who presented with small bowel obstruction secondary to carcinomatosis secondary to primary peritoneal mesothelioma. The patient had multiple risk factors with asbestos exposure and prior therapeutic radiation.

CONCLUSIONS

We discuss the highly varied and elusive presentation of peritoneal mesothelioma. Cumulative asbestos exposure, either directly or indirectly, remains the leading cause of mesothelioma. However, there are other non-asbestos etiologies. Small bowel obstruction often is a late-presenting symptom of widespread tumor burden. A concise review of the current diagnostic and surgical treatment of primary peritoneal mesothelioma demonstrates that early diagnosis and implementation remains vital.

Primary malignant tumors of peritoneal and retroperitoneal origin: clinical and imaging features

Peritoneal carcinomatosis and metastatic involvement of the retroperitoneum are manifestations of many organ-based malignancies and lymphoproliferative disorders. Primary malignancies of peritoneal and retroperitoneal origin occur much less frequently, and are difficult to distinguish from metastatic disease on imaging alone. However, the imaging features of these primary tumors, taken in concert with the clinical data, can be helpful in narrowing the scope of the differential diagnosis. This review presents the clinical and imaging features of primary peritoneal and retroperitoneal tumors arising from the various tissue components that comprise the ligaments, mesenteries, and connective tissues of the peritoneal and retroperitoneal spaces.

Adult abdominal Burkitt lymphoma with isolated peritoneal involvement

Burkitt lymphoma is a fast-growing high grade B-cell neoplasm that rarely affects adults. Three clinical variants are described in the World Health Organization classification: endemic, sporadic, and immunodeficiency-associated. The non-endemic form typically presents as an abdominal mass in children. Symptoms usually occur due to mass effect or direct intestinal involvement. We describe a very unusual presentation of a sporadic Burkitt lymphoma case in a 61-year-old male with diffuse peritoneal and omental involvement, without lymphadenopathies, mimicking peritoneal carcinomatosis.

Malignant mesothelioma

Malignant Mesothelioma (MM) is a rare but rapidly fatal and aggressive tumor of the pleura and peritoneum with limited knowledge of its natural history. The incidence has increased in the past two decades but still it is a rare tumor. Etiology of all forms of mesothelioma is strongly associated with industrial pollutants, of which asbestos is the principal carcinogen. Mesothelioma is an insidious neoplasm arising from mesothelial surfaces i.e., pleura (65%-70%), peritoneum (30%), tunica vaginalis testis, and pericardium (1%-2%). The diagnosis of peritoneal and Pleural mesothelioma is often delayed, due to a long latent period between onset and symptoms and the common and nonspecific clinical presentation. The definite diagnosis can only be established by diagnostic laparoscopy or open surgery along with biopsy to obtain histological examination and immunocytochemical analysis. Different treatment options are available but Surgery can achieve a complete or incomplete resection and Radical resection is the preferred treatment. Chemotherapy has an important role in palliative treatment. Photodynamic therapy is also an option under trial. Patients who successfully underwent surgical resection had a considerably longer median survival as well as a significantly higher 5-year survival.

Source of Data/Study Selection: The data were collected from case reports, cross-sectional studies, Open-label studies and phase –II trials between 1973-2012.

Data Extraction: Web sites and other online resources of American college of surgeons, Medline, NCBI and Medscape resource centers were used to extract data.

Conclusion: Malignant Mesothelioma (MM) is a rare but rapidly fatal and aggressive tumor with limited knowledge of its natural history. The diagnosis of peritoneal and Pleural mesothelioma is often delayed, so level of index of suspicion must be kept high.

Imaging findings in recurrent extramedullary leukaemias

Acute leukaemias are relatively common malignancies. Treatment has advanced significantly in the recent past and there has been improved patient survival. This improved initial response is leading to an increasing number of cases of relapse. Extramedullary relapse occurs in a wide variety of locations with varying presentations, imaging findings and differentials. The pathophysiology and clinical course of recurrent extramedullary myeloid and lymphocytic leukaemias are reviewed in this article. The wide variety of imaging findings associated with many important sites of recurrence and the associated differential diagnosis are discussed and illustrated.

Fever of unknown origin: a clinical mask of malignant peritoneal mesothelioma

The authors present a patient suffering from malignant peritoneal mesothelioma. Differential diagnosis has become the major concern in the fatally ill patient. Pain, increasing abdominal girth, anorexia and weight loss, and recurrent ascites are the most frequent presenting symptoms. In this patient, fever of unknown origin was a clinical mask of mesothelioma. The diagnostic process was focused on infections and collagen-vascular diseases since they are the most common causes of the systemic inflammatory response syndrome. However, persistent pyrexia can also occur, less frequently, in the course of any malignant disease.

CT mimics of peritoneal carcinomatosis

Peritoneal carcinomatosis is a term used to describe widespread metastases of cancerous tumors in the peritoneal cavity. It is most common in carcinomas of the gastrointestinal tract (GIT) and ovaries, and must be considered to be the main diagnosis even when the primary is not known. A wide variety of disease processes mimic peritoneal carcinomatosis. Precise diagnosis based on imaging alone is often difficult and very often the final diagnosis is only obtained after appropriate histopathology or microbiology.

Omental cakes: unusual aetiologies and CT appearances

Background

Omental cakes typically are associated with ovarian carcinoma, as this is the most common malignant aetiology. Nonetheless, numerous other neoplasms, as well as infectious and benign processes, can produce omental cakes.

Methods

A broader knowledge of the various causes of omental cakes is valuable diagnostically and to direct appropriate clinical management.

Results

We present a spectrum of both common and unusual aetiologies that demonstrate the variable computed tomographic appearances of omental cakes.

Conclusion

The anatomy and embryology are discussed, as well as the importance of biopsy when the aetiology of omental cakes is uncertain.

Gardner syndrome complicated with hydronephrosis. A case report

Gardner syndrome is an autosomal dominant disease characterized by the presence of colonic polyposis, osteomas and soft tissue tumors. We present a case of a man who was admitted for a relapse of adenocarcinoma of the rectum. CT-staging showed multiple locations of desmoid tumors and osteomas, with final diagnosis of Gardner syndrome. The follow-up CT, after surgery and chemotherapy, showed a relapse of the lesions with hydronephrosis due to ureteral compression.

Pathways of abdominal tumour spread: the role of the subperitoneal space

The subperitoneal space is a large, unifying, anatomically continuous potential space that connects the peritoneal cavity with the retroperitoneum. This space is formed by the subserosal areolar tissue that lines the inner surfaces of the peritoneum and the musculature of the abdomen and pelvis. It contains the branches of the vascular, lymphatic, and nervous systems that supply the viscera. The subperitoneal space extends into the peritoneal cavity and is invested between the layers of the mesenteries and ligaments that support and interconnect the abdominal and pelvic organs. As such, it provides one large continuous space in which infectious, neoplastic, inflammatory, and hemorrhagic disease may spread in many directions.

Nonvascular mesenteric disease: utility of multidetector CT with 3D volume rendering

Creation of isotropic volumes with submillimeter multidetector computed tomography (CT) has expanded interpretative practice to routinely include two-dimensional (2D) and three-dimensional (3D) postprocessing techniques. Currently, 2D multiplanar reformatting, maximum intensity projection, and 3D volume rendering are available on most workstations. Only volume rendering yields a 3D display that depicts all tissue types from any orientation. Utility is not limited to vascular applications, as 3D volume rendering can be used to evaluate neoplastic, infectious, and inflammatory processes that affect the small-bowel mesentery. Specifically, interactive interpretation of multidetector CT data sets with volume rendering can help characterize nonvascular mesenteric disease, elucidate its extent through more comprehensive display, and facilitate the identification of complications.