Primary cystic peritoneal masses and mimickers: spectrum of diseases with pathologic correlation

Giant intraperitoneal non-pancreatic pseudocyst: a case report

INTRODUCTION

Non-pancreatic pseudocysts are rare lesions that typically form from the omentum and mesentery. These cysts have a thick fibrotic wall made up of fibrous tissue and may show signs of calcifications and inflammatory changes. The fluid inside them can vary, ranging from hemorrhage and pus to serous or sometimes chylous content. In most cases, these cysts appear as a result of trauma, surgery, or infection.

CASE PRESENTATION

A 35-year-old male patient from Ethiopia presented with swelling in his lower abdomen that had been present for 2 years. Initially, the swelling was small but gradually increased in size. The patient experienced frequent urination but no pain or difficulty during urination, urgency, intermittent urination, or blood in the urine. The swelling was initially painless but became painful 2 months prior to his presentation. Abdominal computed tomography scans revealed a well-defined, lobulated peritoneal lesion measuring 16 × 12 × 10 cm, consisting primarily of fluid-filled cysts with a thick, enhancing wall and septa. Additionally, there was a large, heterogeneous enhancing soft tissue component measuring 8 × 6 cm. As a result, the cystic mass was surgically removed in its entirety with partial removal of the bladder wall, and the patient was discharged in an improved condition.

CONCLUSION

Primary non-pancreatic pseudocysts are extremely rare lesions that must be differentiated from other possible causes of cystic lesions within the peritoneal or retroperitoneal regions. Surgeons should be aware of the potential occurrence of these lesions, which may have an unknown origin.

Large cystic lymphangioma of the pancreas: unusual finding with differential diagnosis and therapeutic considerations

Lymphangiomas are rare benign tumours of lymphatic vascular origin. They are more common in the paediatric population and manifest mainly in the neck and axillary region. Retroperitoneal lymphangiomas are <1% and pancreatic origin is even rarer. We present a case of a pancreatic cystic lymphangioma in a 60-year-old woman with chronic diffuse symptoms, diagnosed because of newly onset of diabetes mellitus. She was successfully managed with distal pancreatectomy and spleenectomy en-bloc with the cystic mass without any complications. Cystic lymphangioma of the pancreas is a rare entity presenting with a challenging preoperative diagnosis as imaging modalities may provide ambiguous information. The clinician should be aware of its complicated differential diagnosis and its persistent and subtle symptomatology.

Mesotheliomas and Benign Mesothelial Tumors: Update on Pathologic and Imaging Findings

A diverse spectrum of benign entities and malignant neoplasms originate from the monotonous mesothelium that lines the serosal membranes of the pleural, pericardial, and peritoneal cavities. The mesothelium of myriad sites shows a common origin from the lateral plate mesoderm; primary mesothelial tumors thus demonstrate similar pathogenesis, imaging findings, and treatment options. Significant changes have been made in the 2021 World Health Organization (WHO) classification schemata of the pleural and pericardial tumors on the basis of recent advances in pathology and genetics. While malignant mesotheliomas are biologically aggressive malignancies that occur primarily in patients exposed to asbestos with attendant poor survival rates, well-differentiated papillary mesothelial tumors and adenomatoid tumors charter a benign clinical course with an excellent prognosis. Mesothelioma in situ is a newly characterized entity represented by recurrent unexplained pleural effusions without any identifiable mass at imaging or thoracoscopy. Immunohistochemical markers based on BAP1, MTAP, CDKN2A, and TRAF7 gene mutations help differentiate diffuse mesotheliomas from benign mesothelial proliferations and localized mesotheliomas. Cross-sectional imaging modalities, including US, CT, MRI, and fluorine 18-fluorodeoxyglucose (FDG) PET/CT, permit diagnosis and play a major role in staging and assessing surgical resectability. Imaging studies are invaluable in providing noninvasive and quantitative assessment of tumor response in patients with unresectable disease. Owing to significant overlap in patient characteristics and pathomorphology, accurate diagnosis based on advanced histopathology techniques and genetic abnormalities is imperative for optimal management and prognostication. While patients with nonepithelioid pleural mesotheliomas benefit from immunotherapy, novel targeted therapies for CDKN2A-, NF2-, and BAP1-altered mesotheliomas are under consideration. ^© RSNA, 2023 Quiz questions for this article are available through the Online Learning Center.

Peritoneal disease: key imaging findings that help in the differential diagnosis

The peritoneum is a unique serosal membrane, which can be the site of primary tumors and, more commonly, secondary pathologic processes. Peritoneal carcinomatosis is the most common malignant condition to affect the peritoneal cavity, and the radiologist plays an important role in making the diagnosis and assessing the extent of disease, especially in sites that may hinder surgery. In this review, we address the role of the radiologist in the setting of peritoneal pathology, focusing on peritoneal carcinomatosis as this is the predominant malignant process, followed by revising typical imaging findings that can guide the differential diagnosis.We review the most frequent primary and secondary peritoneal tumor and tumor-like lesions, proposing a systemic approach based on clinical history and morphological appearance, namely distinguishing predominantly cystic from solid lesions, both solitary and multiple.

Bubbles in the belly- a case based approach to cystic peritoneal masses

Background

Primary cystic neoplasms of the peritoneum are rare lesions and not commonly encountered in practice. Many intra-abdominal processes may mimic cystic masses within the peritoneal cavity and pose a diagnostic challenge to both the pathologist and radiologist. Clinical presentation is diverse and varied. These lesions are usually benign. Hence complete surgical excision is the treatment of choice in most of the cases.

Methods

Study design: Descriptive Retrospective study.

Cystic peritoneal lesions were identified and studied from data over a period of 5 years in the Histopathology Section at a tertiary care hospital in Pune, India. Mode of presentation, imaging findings in addition to gross and histopathologic findings of these lesions were studied.

Results

Out of 50 peritoneal lesions studied over a period of 5 years, only 7 were identified to be cystic peritoneal masses.

Of these two were found to be peritoneal cysts, two mesenteric cysts, one an infected mesenteric cyst and one each a mucinous cystadenoma and lymphangioma.

Conclusions

Correct diagnosis rests in the hands of the pathologist and ensures that the patient receives appropriate and timely management. Hence knowledge of the spectrum of these rare cystic peritoneal masses is necessary to distinguish from other potential cystic abdominal mimicker masses and avoid a potential pitfall.

Calcified pseudocyst: an uncommon presentation of chronic pancreatitis

Pseudocysts are localised fluid collections, usually developing as a complication of acute or chronic pancreatitis. Pancreatic ductal or parenchymal calcifications are commonly seen in routine radiological imaging, but calcification of pseudocyst is extremely rare. Calcified pseudocysts have been reported in literature as case reports, but a calcified pseudocyst in the lesser sac, without underlying pancreatic calcification, has not been reported. We report a case of a pancreatic pseudocyst with a calcified wall, requiring surgical excision and histological examination confirming the diagnosis.

Approach to Cystic Lesions in the Abdomen and Pelvis, with Radiologic-Pathologic Correlation

Cystic lesions found in and around the peritoneal cavity can often be challenging to diagnose owing to significant overlap in imaging appearance between the different entities. When the cystic lesion can be recognized to arise from one of the solid abdominal organs, the differential considerations can be more straightforward; however, many cystic lesions, particularly when large, cannot be clearly associated with one of the solid organs. Cystic lesions arising from the mesentery and peritoneum are less commonly encountered and can be caused by relatively rare entities or by a variant appearance of less-rare entities. The authors provide an overview of the classification of cystic and cystic-appearing lesions and the basic imaging principles in evaluating them, followed by a summary of the clinical, radiologic, and pathologic features of various cystic and cystic-appearing lesions found in and around the peritoneal cavity, organized by site of origin. Emphasis is given to lesions arising from the mesentery, peritoneum, or gastrointestinal tract. Cystic lesions arising from the liver, spleen, gallbladder, pancreas, urachus, adnexa, or soft tissue are briefly discussed and illustrated with cases to demonstrate the overlap in imaging appearance with mesenteric and peritoneal cystic lesions. When approaching a cystic lesion, the key imaging features to assess include cyst content, locularity, wall thickness, and presence of internal septa, solid components, calcifications, or any associated enhancement. While definitive diagnosis is not always possible with imaging, careful assessment of the imaging appearance, location, and relationship to adjacent structures can help narrow the differential diagnosis. Online supplemental material is available for this article. ^©RSNA, 2021.

Solitary pelvic primary intraperitoneal hydatid managed with a minimal access approach: A case report

Solitary primary pelvic intraperitoneal hydatid cysts are rare. We report the case of a 22-year-old women who presented with a dull ache in her lower abdomen for 2 years and increased urinary frequency over 3 months. Ultrasonography and CT indicated a solitary primary peritoneal pelvic hydatid cyst. Hydatid serology was positive. Perioperative albendazole was prescribed and laparoscopic cystectomy planned. Intraoperatively, dense adhesions to the omentum, urinary bladder, and left fallopian tube were taken down laparoscopically. A small Pfannenstiel incision was made to separate the bladder's left lateral edge and deliver the cyst externally. This report details our experience of managing this case and reviews pertinent literature.

An unusual presentation of acute abdomen: infarcted peritoneal cyst-a probable asbestos-related benign cystic mesothelioma

This is a report of a rare case of an infarcted pelvic intra-abdominal cyst, having no mesenteric connection presenting as an acute abdomen. The patient had significant asbestos exposure. The cyst was treated successfully by surgical excision. Histopathology showed an infarcted cyst; the lining was destroyed, precluding marker studies. A diagnosis of benign cystic peritoneal mesothelioma (BCPM) was made by excluding other causes of solitary pelvic intra-abdominal cysts. BCPM has been classified as an asbestos-related neoplasm and is usually seen in the pelvis adjunct to the urinary bladder. One-year post-surgery, there was no recurrence. The case report shows that infarcted pelvic mesothelial cysts can present as an acute abdomen and can be treated successfully by total excision with no recurrence.

Imaging features, complications and differential diagnoses of abdominal cystic lymphangiomas

PURPOSE

The aim of the study is to describe the imaging features, complications and differential diagnoses of abdominal cystic lymphangiomas (ACLs).

RESULTS

ACLs are benign lymphatic malformations that mainly arise in the subperitoneal space and the retroperitoneum. The typical presentation of an ACL is a multilocular lesion with homogenous serous content, presenting a thin wall and septa, usually free from adjacent organ compression. Atypical findings, including fat or hemorrhagic content, septal calcifications and unilocular presentation, are not uncommon. Rarely, ACLs can be revealed by acute complications, such as infection, hemorrhage, intussusception, complications with a twisting mechanism (including torsion around its own pedicle) or spontaneous rupture, which can be diagnosed by imaging. Ultrasonography and CT are the most useful modalities in emergency situations. MRI performs best in the noninvasive characterization of cystic lesions. ACLs should be differentiated from normal anatomic structures (e.g., cisterna chyli) or pitfalls (e.g., ascites, extrapancreatic necrosis, lymphocele) that can simulate ACLs. Among other primary peritoneal cystic lesions, benign cystic mesothelioma can be difficult to differentiate from ACL. Some neoplastic peritoneal lesions may have cystic components or content that looks like fluid on imaging (such as mucinous or myxoid content) and be misdiagnosed as ACL. Nodular or thick enhancement of the wall or septa should then be considered worrisome features and should not suggest ACL. ACLs mostly require a simple follow-up. If treatment is necessary, percutaneous sclerotherapy is a safe and effective alternative to surgery.

CONCLUSION

Imaging, especially MRI, allows the noninvasive diagnosis of ACL and helps to exclude potential malignant differential diagnoses.

Imaging spectrum of mesenteric masses

Mesenteries are extensions of the visceral and parietal peritoneum consisting of fat, vessels, nerves, and lymphatics. Mesenteric masses have a wide differential diagnosis with neoplastic, infectious, or inflammatory etiologies and can either be solid or cystic. Imaging features are critical for the diagnosis. We review the epidemiology, imaging spectrum, and differentiating features and treatment of mesenteric masses.

Unravelling the Mysteries of the Mesentery

The mesentery and its folds tether the small bowel loops to the posterior abdominal wall. It transmits nerves, vessels, and lymph ensconced in a fatty sponge layer wrapped in a thin glistening peritoneum, from and to the small bowel. Not only does this flexible dynamic fatty apron house various localized primary benign and malignant lesions, it is often involved in and gives an indication of generalized or systemic diseases in the body. An understanding of the anatomy, components, and function of the mesentery helps to classify mesenteric abnormalities. This further allows for characterizing radiological patterns and appearances specific to certain disease entities. Recent reviews of mesenteric anatomy have kindled new interest in its function and clinical applications, heralding the possibility of revision of its role in diseases of the abdomen.

Primary and secondary diseases of the perinephric space: an approach to imaging diagnosis with emphasis on MRI

The perinephric space is the middle compartment of the retroperitoneum, containing the kidneys and adrenal glands. Differential considerations for diseases involving primarily the perinephric space differ from those arising from the kidney itself, show variant imaging features, and require identification and characterisation by interpreting radiologists-an imaging diagnosis can be suggested in many cases. Lymphangiomas are congenital cystic lesions that may contain lipid-laden chyle, which may be detectable on magnetic resonance imaging (MRI). Retroperitoneal fibrosis, Erdheim-Chester disease, and lymphoma may present as a perinephric soft tissue rind. Osseous findings favour Erdheim-Chester, ureteric obstruction favours retroperitoneal fibrosis, and associated lymphadenopathy with mass-effect, but without invasion of adjacent structures favours lymphoma. Extramedullary haematopoiesis and brown fat stimulation are both characterised by signal drop on opposed-phase T1-weighted (W) images, the former resulting from severe anaemia and the latter in the context of elevated serum catecholamines, especially in the setting of phaeochromocytoma. Liposarcoma is the most common primary sarcoma of the retroperitoneum. Metastases are uncommon; however, they can be seen in melanoma, among other primary malignancies. Increased T1W signal hyperintensity is typical of melanoma metastases and haematomas. Abscesses show non-enhancing fluid centrally with marked diffusion restriction. This article presents a review of the perinephric space, pathological conditions of the perinephric space, and an approach towards imaging and diagnosis using cross-sectional imaging, with emphasis on MRI. MRI provides better tissue characterisation, assessment of enhancement kinetics, and detection of intralesional fat in comparison to CT. Clinical and laboratory correlation or tissue sampling may be required for definitive diagnosis in some cases.

Abdominal lymphatic malformations

BACKGROUND

Abdominal lymphatic malformations (LM) are relatively rare findings in the differential diagnosis of focal abdominal lesions; however, they represent a challenge especially in younger patients. The aim of this review article is to provide up-to-date information about the different kinds of LM manifestations. In addition, related syndromes and typical imaging features to facilitate the diagnosis are discussed.

RESULTS

The clinical presentation of abdominal LM is unspecific, whereby most are asymptomatic and comprise incidental findings of thin-walled cystic masses anywhere in the abdomen. The fluid in the cystic masses may be proteinaceous, contain blood, or be infected. Radiological imaging features overlap with other cystic diseases; hallmark in LM is a lack of a solid component and exclusive enhancement of the walls and septa.

CONCLUSION

In cystic abdominal masses in early childhood or young adults, abdominal LM must be taken into account by the radiologist. Newly defined entities in this spectrum of diseases are central conducting lymphatic anomaly (CCLA) and generalized lymphatic anomaly (GLA).

Imaging findings for mucinous tumors of the abdomen and pelvis

This article aims to describe the imaging findings for mucinous tumors of the abdomen and pelvis, which have a similar appearance on imaging tests regardless of the organ in which they develop. Due to the high water content of mucus, the appearance of these tumors is generally similar to that of water on ultrasonography, computed tomography, and magnetic resonance imaging. Another common feature of mucin-producing tumors is that calcifications are often present. The rupture of these lesions and accumulation of mucinous material in the peritoneal cavity gives rise to pseudomyxoma peritonei. It is important to identify mucinous tumors because they have a different prognosis and clinical course than non-mucinous tumors and require different management. Depending on their anatomic location and their imaging characteristics, the treatment approach varies from follow-up to radical surgery together with chemotherapy or radiotherapy or both.

Ultrasound characteristics of a symptomatic and asymptomatic lymphocele after pelvic and/or paraaortic lymphadenectomy

OBJECTIVE

To describe the sonographic characteristics of a lymphocele after pelvic and/or paraaortic lymphadenectomy for gynecological malignancy, analyze and identify ultrasound characteristics related to the symptomatic and asymptomatic lymphoceles.

MATERIALS AND METHODS

This is a retrospective analysis of ultrasound examination data collected consecutively in patients after pelvic and/or paraaortic lymphadenectomy in one institution. We recorded the number of lymphoceles, localization, size; ultrasound morphology following International Ovarian Tumor Analysis group classification and symptoms.

RESULTS

We described and analyzed 227 lymphoceles (150 asymptomatic and 77 symptomatic) in 161 patients. The asymptomatic lymphocele is typically a thick-walled cystic lesion without vascularization, round and unilocular with anechoic or ground-glass content. The symptomatic lymphocele is typically an oval, or ovoid, unilocular lesion with low-level or anechoic content (ground glass content is unlikely to be present, p < 0.001) and the presence of debris and septations. The lymphocele size (p = 0.001), number of lymphoceles (>1) (p = 0.005), septa (p = 0.002), and debris (p < 0.001) were independent ultrasound features correlating to symptoms development. More than one lymphocele (p = 0.047), septations (p = 0.007) and presence of debris (p < 0.001) were independent ultrasound features correlated to infection.

CONCLUSION

Ultrasound features of symptomatic and asymptomatic lymphocele differ. The clues for lymphocele differential diagnosis are the history of lymphadenectomy and the finding cystic lesion with typically ultrasound features of lymphocele, adjacent to great pelvic vessels. Unique ultrasound features of lymphocele may help to distinguish from tumor relapse, hematoma, abscess, seroma or urinoma.

Enterogenous cyst of the small bowel mesentery: a case report and review of the literature

INTRODUCTION

Enterogenous cysts are a very rare congenital abnormality that can be found anywhere within the gastrointestinal tract, most commonly in the small intestine. The incidence is approximately one in 4500-10,000 live births. Diagnosis can be suggested by ultrasound (US), computed tomography (CT) scans or magnetic resonance imaging (MRI) findings, although histological examination confirms the definitive diagnosis.

PATIENTS

We present a case of enterogenous cyst in an adult female who underwent a resection of the tumour.

RESULTS

After two years of observation, there is no evidence of tumour recurrence.

MRI of the bowel - beyond inflammatory bowel disease

MR enterography is traditionally used to evaluate inflammatory bowel disease (IBD) both at initial presentation and at follow-up. MR enterography can also be used to evaluate non-IBD conditions such as polyps or other masses of the gastrointestinal tract. In this article, we emphasize how to recognize bowel conditions beyond IBD on conventional abdominal MRI without a specific enterographic technique. In this overview we discuss common and uncommon pediatric bowel conditions beyond IBD seen on MRI including infectious and inflammatory conditions, congenital diseases and tumor and tumor-like conditions. Radiologists should become familiar with the salient imaging features of these bowel conditions to help guide management.

Chronic Encapsulated Seroma Persisting for Three Years after Abdominoplasty and a Successful Surgical Solution

Abdominoplasty is listed among five most common esthetic surgical procedures in the Western World. Despite all efforts, abdominoplasty bears a high risk of complications. We observed a 39-year-old-woman with previous classical abdominoplasty performed elsewhere three years ago. Clinical examination demonstrated a swollen and tense abdominal mass. Laboratory findings were normal. Clinical examination was completed by abdominal ultrasonography which demonstrated both, a significant fluid volume in this area and a dense fibrous “capsule”. The diagnosis was a late or chronic encapsulated seroma with a thick pseudocapsule or “bursa”. We performed a revision abdominoplasty with a standard supra-fascial dissection. Surgical resection of infra-umbilical flap containing skin, subcutaneous tissue and capsulectomy were performed under general anaesthesia. A new umbilicus was created attaching small skin flaps in the muscular fascia. No drains were used. We observed no seroma formation. Follow up after six and ten months was unremarkable. The fibrous pseudocapsule of chronic seroma results in different degrees of deformities, abdominal scar deviation and asymmetry. Surgical capsulectomy combined with revision abdominoplasty with preservation of Scarpa’s fascia and placement of progressive tension sutures resulted in being effective and leads an esthetic outcome without seroma recurrence.

Massive endometrioma presenting with dyspnea and abdominal symptoms

An abdominal mass may present with a myriad of symptoms resulting from compression of surrounding organs. A major clinical challenge with practical implications is accurate preoperative identification of the origin of the mass. Here, we present the case of a 29-year-old female patient with abdominal distension and shortness of breath for approximately 6 weeks before presentation. A large abdominal mass compressing the surrounding organs was observed on abdominal x-ray and computed tomography of the abdomen and pelvis. Preoperative imaging was unable to identify the organ of origin; pathologic and histologic analyses of the tumor ultimately identified a rare, massive intra-abdominal endometrioma, freely floating within the peritoneum and fed by an omental blood supply. This case highlights the importance of considering an atypical presentation of endometriosis in women of reproductive age with abdominal complaints.

Magnetic resonance imaging of fetal pelvic cysts

The detection of fetal anomalies has improved in the last years as a result of the generalization of ultrasound pregnancy screening exams. The presence of a cystic imaging in the fetal pelvis is a relatively common finding, which can correspond to a real congenital cystic lesion or result from the anomalous liquid accumulation in a whole pelvic organ, mainly the urinary bladder, the uterus, or the vagina. In selected cases with poor prognosis and/or inconclusive echographic findings, magnetic resonance may bring additional information in terms of the characterization, anatomical location, and real extension of the pathology. This pictorial essay describes the normal pelvic fetal anatomy, as well as the most common pelvic cysts. It also describes the causes of an anomalous distension of the whole pelvic organs detected in utero, with emphasis on prenatal magnetic resonance imaging exams. Moreover, it proposes practical teaching points to reduce the differential diagnosis of these lesions based on the sex of the fetus, the division of the pelvis in anatomical spaces, and the imaging findings of the pathology. Finally, it discusses the real utility of complementary MRI.

Cystic Lymhangioma of the Lesser Sac in Adult Presenting with Features of Gastric Outlet Obstruction - A Case Report

Cystic lymphangioma is a paediatric benign tumour, occurs commonly in head and neck region. Adult intraabdominal lymphangiomas are uncommon and only few cases of lesser sac cystic lymphangioma are reported in the literature. We present a case of lesser sac cystic lymphangioma in a 26-year-old lady who presented with features of gastric outlet obstruction. Clinical examination revealed a 10x10 cm firm, non tender, mobile intraabdominal lump in the epigastrium. An upper gastrointestinal endoscopy showed possible external compression at the body of the stomach. Ultrasound demonstrated a multicystic lesion, with internal echoes in one locule. CECT showed a large multiloculated cystic lesion with hyper-dense content in the lesser sac extending up to the left lobe of the liver and indenting the stomach, lesser sac, and upper border of pancreas. On surgical exploration, a 10X8 cm multi cystic lesion with clear fluid was found in the lesser sac very close to the lesser curvature of stomach. Histopathological examination of the excised lesion showed features of cystic lymphangioma. Though very rare, intraabdominal cystic lymphangiomas should be considered in all atypical cases of gastric outlet obstruction. A reasonable knowledge about these benign lesions will aid in establishing the diagnosis and surgical management.