Multilocular Peritoneal Inclusion Cysts Research Articles

Large and Extensive Multilocular Peritoneal Inclusion Cysts Lack Genomic Alterations and Follow an Indolent Clinical Course Despite Rare Recurrences.

Peritoneal inclusion cysts (PICs) are unilocular or multilocular cystic lesions lined by bland mesothelial cells. While most are small and localized, rare examples may be large or multifocal with diffuse peritoneal involvement, causing clinical and even pathologic concern for malignancy. We examined 20 PIC, including 8 large solitary and 12 multifocal lesions. Solitary PIC were found in 7 female and 1 male patients ranging from 19 to 55 (median: 37) years. Expanded collagenous (n=2) or edematous (n=1) areas were occasionally seen in the septae, and 1 had microscopic foci of myxoid stroma. Four had hobnail cells, and 1 had minor areas of papillary mesothelial hyperplasia. Multifocal PICs occurred in 9 female and 3 male patients ranging from 26 to 80 (median: 53) years. Three showed extensive associated fibrosis with entrapment of preexisting adipose tissue, 2 had areas resembling granulation tissue, and 3 had scattered foci of myxoid stroma. Hobnail cells were present in 9, papillary mesothelial hyperplasia in 2, entrapped single cells in 1, and 2 had areas resembling adenomatoid tumors. Two of the multifocal PICs had limited local recurrences at 18 and 21 months. No patients died of disease. Clonal alterations were not identified in any of the tested PICs (mutational and fusion analysis in 5, chromosomal microarray in 1). Despite limited local recurrences, we demonstrate that even large and multifocal PICs may lack identifiable genomic alterations and are associated with benign outcomes.

Multiloculated peritoneal inclusion cyst in male patient: a case report

Multilocular peritoneal inclusion cyst (MPIC), also known as benign multicystic peritoneal mesothelioma, is a rare mesothelial lesion arising from the peritoneal mesothelium. This condition most commonly occurs in females of reproductive age group and are very rare in males. We report a case of young male patient, presented with the chief complaint of lower abdominal pain, without any previous history of surgery. After radiological investigations which were suggestive of pelvic inclusion cysts, pt. was planned for diagnostic laparoscopy (D/L). On D/L, multiple free-floating cysts were found in pelvis between rectum and bladder which were successfully extracted and sent for histopathological examination (HPE). HPE confirmed it to be MPIC.

Benign multicystic mesothelioma and peritoneal inclusion cysts: are they the same clinical and histopathological entities? A systematic review to find an evidence-based management.

Peritoneal mesothelial cysts (PMC) are a clinical dilemma because of their true pathogenic nature. Many definitions have been associated with PMC, including "benign multicystic mesothelioma", "cystic mesothelioma", "multilocular peritoneal inclusion cysts", ''inflammatory cysts of the peritoneum" or "postoperative peritoneal cyst". We herein performed a systematic review of the literature focusing on clinical and histopathological aspects of PMC, diagnosis, and therapies. Moreover, we described our experience with a case of PMC in a young female. Since there is often a history of prior surgery or inflammatory disease, most authors consider PMC of reactive origin. However, in some cases they occur without any documentable signs of disease or injury. A variety of clinical findings can complicate the preoperative assessment and a multitude of histological pictures may potentially lead to a misdiagnosis. The absence of a uniform treatment strategy and lack of long-term follow-up often hinder the accurate definition leading to unnecessary or unnecessarily aggressive therapy. PMC are more common than had previously been thought. Most authors consider them non-neoplastic; thus the designation of "peritoneal inclusion cyst" is preferable. The term "mesothelioma" should be used only in cases of histological evidences of atypia. The high rates of recurrence suggest that the goal of treatment should not be necessarily complete eradication, but symptomatic relief through individualized treatment. This is a topic of particular importance, especially in young female where recurrence rates could be lower than those reported in adults and where an improperly aggressive treatment could have repercussions on fertility.

Mucinous Cystic Adenoma of Ovary Mimicking as Multilocular Peritoneal Inclusion Cyst on Imaging-A Case Report

Mucinous Cystic Adenoma of Ovary Mimicking as Multilocular Peritoneal Inclusion Cyst on Imaging-A Case Report

Adenomatoid tumors of the male and female genital tract are defined by TRAF7 mutations that drive aberrant NF-kB pathway activation.

Adenomatoid tumors are the most common neoplasm of the epididymis, and histologically similar adenomatoid tumors also commonly arise in the uterus and fallopian tube. To investigate the molecular pathogenesis of these tumors, we performed genomic profiling on a cohort of 31 adenomatoid tumors of the male and female genital tracts. We identified that all tumors harbored somatic missense mutations in the TRAF7 gene, which encodes an E3 ubiquitin ligase belonging to the family of tumor necrosis factor receptor-associated factors (TRAFs). These mutations all clustered into one of five recurrent hotspots within the WD40 repeat domains at the C-terminus of the protein. Functional studies in vitro revealed that expression of mutant but not wildtype TRAF7 led to increased phosphorylation of nuclear factor-kappa B (NF-kB) and increased expression of L1 cell adhesion molecule (L1CAM), a marker of NF-kB pathway activation. Immunohistochemistry demonstrated robust L1CAM expression in adenomatoid tumors that was absent in normal mesothelial cells, malignant peritoneal mesotheliomas, and multilocular peritoneal inclusion cysts. Together, these studies demonstrate that adenomatoid tumors of the male and female genital tract are genetically defined by TRAF7 mutation that drives aberrant NF-kB pathway activation.

Genomic profiling of malignant peritoneal mesothelioma reveals recurrent alterations in epigenetic regulatory genes BAP1, SETD2, and DDX3X

Malignant mesothelioma is a rare cancer that arises from the mesothelial cells that line the pleural cavity and less commonly from the peritoneal lining of the abdomen and pelvis. Most pleural mesotheliomas arise in patients with a history of asbestos exposure, whereas the association of peritoneal mesotheliomas with exposure to asbestos and other potential carcinogens is less clear, suggesting that the genetic alterations that drive malignant peritoneal mesothelioma may be unique from those in pleural mesothelioma. Treatment options for all malignant mesotheliomas are currently limited, with no known targeted therapies available. To better understand the molecular pathogenesis of malignant peritoneal mesothelioma, we sequenced 510 cancer-related genes in 13 patients with malignant mesothelioma arising in the peritoneal cavity. The most frequent genetic alteration was biallelic inactivation of the BAP1 gene, which occurred in 9/13 cases, with an additional two cases demonstrating monoallelic loss of BAP1. All 11 of these cases demonstrated loss of BAP1 nuclear staining by immunohistochemistry, whereas two tumors without BAP1 alteration and all 42 cases of histologic mimics in peritoneum (8 multilocular peritoneal inclusion cyst, 6 well-differentiated papillary mesothelioma of the peritoneum, 16 adenomatoid tumor, and 12 low-grade serous carcinoma of the ovary) demonstrated intact BAP1 nuclear staining. Additional recurrently mutated genes in this cohort of malignant peritoneal mesotheliomas included NF2 (3/13), SETD2 (2/13), and DDX3X (2/13). While these genes are known to be recurrently mutated in pleural mesotheliomas, the frequencies are distinct in peritoneal mesotheliomas, with nearly 85% of peritoneal tumors harboring BAP1 alterations versus only 20–30% of pleural tumors. Together, these findings demonstrate the importance of epigenetic modifiers including BAP1, SETD2, and DDX3X in mesothelial tumorigenesis and suggest opportunities for targeted therapies.

Selected topics in peritoneal pathology.

This essay considers selected peritoneal lesions many of which were the subject of studies coauthored by Dr Robert E. Scully. His article on multilocular peritoneal inclusion cysts has largely led to these lesions being considered non-neoplastic, eschewing the term cystic mesothelioma. These cysts are often associated with reactive mural mesothelial proliferations that can potentially lead to a misdiagnosis of mesothelioma. Clinical findings, such as a common association with endometriosis or prior operations, can prompt consideration of a reactive lesion. Mesothelial hyperplasia may be difficult to distinguish, when florid, from mesothelioma but a variety of gross and microscopic features will aid their recognition. Nodular peritoneal aggregates of histiocytes (sometimes admixed with mesothelial cells) may occasionally be a striking finding that can be misdiagnosed as a metastasis if the patient has a known neoplasm. Appreciation of their bland nuclear features and histiocytic nature, confirmed by immunohistochemical markers, facilitate the diagnosis. Various forms of peritonitis are briefly considered including sclerosing peritonitis, a process sometimes associated with luteinized thecomas (thecomatosis) of the ovaries, an entity first appreciated by Dr Scully. Mesotheliomas are briefly reviewed emphasizing the caution that should be used in applying the designation "well-differentiated papillary mesothelioma." Many interpret the latter as benign, but multifocal lesions must be thoroughly examined histologically because of potential overlapping features with malignant mesothelioma. The morphologic spectrum of malignant mesothelioma and its usually straightforward distinction from müllerian neoplasms is considered, as is its occasional presentation as a dominant ovarian mass. The spectrum of low-grade serous peritoneal neoplasms including the "psammocarcinoma" is reviewed. Finally, various benign müllerian lesions, particularly endometriosis and endosalpingiosis, may be conspicuous in peritoneal specimens and sometimes are grossly striking. The usual presence of benign endometrioid epithelium and stroma should facilitate the correct diagnosis of endometriosis, but in cases in which the stroma is atrophic or the sole component (stromal endometriosis), diagnostic problems may arise.

Benign multicystic peritoneal mesothelioma: A rare case presenting as pneumoperitoneum and pneumotosis intestinalis.

Benign multicystic peritoneal mesothelioma (BMPM) is a rare peritoneal lesion that commonly presents as lower abdominal pain, palpable mass, or both. A case of BMPM presenting as pneumoperitoneum and pneumotosis intestinalis is described. Utilizing PubMed, a review of the literature was performed using the search words “benign multicystic peritoneal mesothelioma,” “multilocular peritoneal inclusion cysts,” “pneumoperitoneum,” and “pneumotosis intestinalis.” Although this lesion is typically benign, it has a high recurrence rate as well as the potential for malignant transformation; it is important to confirm the diagnosis in a minimally invasive manner, and to formulate a surgical treatment strategy to avoid unnecessary re-operations.

Quiste de inclusión peritoneal multilocular: una extraña lesión pélvica

Multilocular peritoneal inclusion cyst, also known as benign multicystic mesothelioma, is a rare lesion found on the peritoneal surface. The etiology is unknown but the lesion usually occurs in premenopausal women.Clinically the most frequent findings are chronic pain, a palpable mass and distension of the abdomen, although this cyst can also be asymptomatic or present as an acute abdomen. The diagnosis is usually given by ultrasonography and the currently recommended primary therapy is surgical excision, although high recurrence rates have been reported. We report the case of a 24- year-old woman with acute abdominal pain managed by laparoscopy and removal of the mass.

Multiloculated Peritoneal Inclusion Cysts with Splenic Involvement: A Case Report

Multilocular peritoneal inclusion cysts (MPICs) are most commonly found in women of reproductive years and involve the abdomen, pelvis, and retroperitoneum. It is commonly thought that these cysts are due to an inflammatory reaction. Patients usually present with chronic abdominal or pelvic pain and are diagnosed by ultrasound or CT scan. Although there are experimental medical treatment options surgical excision remains the current recommended primary therapy for symptomatic disease. The following case describes a pregnant female with rare MPIC involving the spleen and peritoneum. Biological behavior of MPIC and current therapy options are also discussed.

Pathology of the peritoneum: a review of selected topics.

Mesothelial lesions of the peritoneum may pose significant diagnostic problems. Accurate identification of these lesions is important because of their distinctive behavior and treatment requirements. This review discusses the clinical, pathological, and differential diagnosis of a variety of mesothelial lesions of the peritoneum, which includes mesothelial hyperplasia, multilocular peritoneal inclusion cysts (benign cystic mesothelioma), well-differentiated papillary mesotheliomas, and diffuse malignant mesothelioma, and the role of immunohistochemistry in the distinction from the more common primary peritoneal serous carcinomas. In addition, borderline serous tumors, psammocarcinomas, and solitary fibrous tumors of the peritoneum are briefly mentioned.

Multilocular peritoneal inclusion cysts (so-called cystic mesotheliomas).

Twenty-five cases of multilocular peritoneal inclusion cysts (MPIC) were investigated. All but four cases were associated with a history of a previous abdominal or pelvic operation, or evidence of endometriosis or pelvic inflammatory disease, or combinations of these findings. All of the lesions were attached to pelvic organs, 44% also occupied the upper abdominal cavity, and 16% involved the retroperitoneum. In three cases free-floating cysts were present as well. The median diameter of the lesions was 13 cm. The cyst locules were lined by one to several layers of flat to cuboidal mesothelial cells that occasionally formed papillae, had a hobnail shape, or had undergone squamous metaplasia. The stroma was characterized by chronic inflammation and often acute inflammation. In most of the cases there was mural proliferation of the mesothelial cells, occasionally simulating a malignant mesothelioma. Twelve lesions were complicated by postoperative local recurrence; in four of these cases the recurrences were multiple; neither the size of the lesion nor the presence of mural mesothelial proliferation influenced the outcome. The clinical and pathologic data in this series suggest that the MPIC is a nonneoplastic reactive mesothelial proliferation.