Mesothelial Cysts

Abstract

Objectives Peritoneal mesothelial cysts have been reported under various terms, including benign cystic mesothelioma, usually in the form of case reports/series, whereas extraperitoneal cases are rarely reported. Our objective was to report the detailed characteristics of cystic lesions of the serosal cavities. Methods We retrospectively examined the clinicopathologic findings of a series of mesothelial cystic lesions (n = 79). Results Most cases (n = 68, 86%) concerned the peritoneum, whereas 11 (14%) concerned the pericardium. No pleural cases were found. A total of 51 (64.5%) lesions were solitary, whereas 28 (35.5%) were multiple. Peritoneal lesions harbored a plump eosinophilic mesothelium and a loose connective stroma, whereas pericardial lesions showed a cuboidal/flattened mesothelium, collagenous stroma, intense inflammation, and other tissue types, like adipose and muscle tissue. Solitary peritoneal lesions are usually extrapelvic and found in older patients incidentally during other surgeries, whereas multiple lesions are found in younger patients and usually in the pelvis. The lesions show a benign clinical course with rare recurrences but no malignant transformation. Conclusions Most mesothelial cysts are peritoneal and rarely pericardial. Peritoneal cysts differ from pericardial cysts. Peritoneal solitary lesions differ from multiple lesions, also suggesting their pathogenetic differences.

Mesenteric and Retroperitoneal Mucinous Cystic Neoplasms: A Case Series

“…Both of these entities can become tumefactive forming large cystic masses. 14,15 However, the absence of mucinous epithelium and ovarian-type stroma are important distinguishing factors to separate these entities from MCNs.…”

L1CAM expression in cystic mesothelial lesions: a comparison with adenomatoid tumours, well‐differentiated papillary mesothelial tumours and malignant mesotheliomas

“…Another lesion that could be included in the family of benign mesothelial lesions is the socalled 'multicystic mesothelioma'. 4 The exact nature of this lesion, reactional or neoplastic, has been a matter of debate for decades, and their varied terminology proves the uncertainty. 4 Given their common mesothelial origin, we aimed to explore the possible expression of L1CAM in a large series of cystic mesothelial lesions.…”

“…The current mesothelial cystic lesions are part of a cohort, the detailed clinicopathological characteristics of which have been previously described. 4 Briefly, the cystic lesions were solitary (n = 38, 66.7%) or multiple (n = 19, 33.3%), of peritoneal (n = 47, 82.5%) or pericardial (n = 10, 17.5%) localisation. None of the mesothelial cystic lesions expressed L1CAM (Figure 1).…”

“…A possible relationship between mesothelial cystic lesions, WDPMTs and ATs has been suspected. 1,4 However, the absence of L1CAM expression probably suggests a different aetiopathogenetic model for mesothelial cystic lesions in comparison to the two other tumours.…”

“…3 Other rarer epithelial tumours include cystadenoma and mixed epithelial stromal tumour (MEST) with <30 reported cases from the SVs. 1,4,5 Both of these tumours show cystic epithelium, and they are thought to form part of a single tumour spectrum, with MEST being distinguished by its more cellular fibromuscular stromal component. 5 Cystadenomas are considered to be benign, whereas MEST ranges from low-grade to high-grade neoplasms, according to its stromal cellularity and stromal atypia.…”