Collagenous Spherulosis in Well-Differentiated Papillary Mesothelioma in a Female With Multilocular Peritoneal Inclusion Cysts

Our plain-English summary of Collagenous Spherulosis in Well-Differentiated Papillary Mesothelioma in a Female With Multilocular Peritoneal Inclusion Cysts, by B. AbdullGaffar, L.G. Raman (International Journal of Surgical Pathology, 2019).

The study

• Authors: B. AbdullGaffar, L.G. Raman
• Journal: International Journal of Surgical Pathology
• Published: 2019;27(4):427-431
• Type of article: Case report
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Multilocular peritoneal inclusion cysts are mesothelial tumor-like lesions with or without small foci of florid papillary mesothelial hyperplasia that might simulate serous epithelial papillary lesions or well-differentiated papillary mesothelioma (WDPM) of the peritoneum. The papillary cores in papillary mesothelial hyperplasia and in WDPM display a variety of different histomorphologic features. To our knowledge, collagenous spherulosis in WDPM was not previously described or illustrated in the literature. Collagen spherules have been described in several miscellaneous benign and malignant lesions of the breast, prostate, salivary gland, and cutaneous adnexal tumors. They sometimes impose a diagnostically challenging cribriform growth pattern. We report a case of a young adult woman who presented with a large painful palpable multicystic mass in the right iliac fossa and pelvis. Histologically, it showed features of multilocular peritoneal inclusion cysts with an incidental finding of a small nodule demonstrating morphologic and immunohistochemical features of WDPM. The papillary cores revealed uniform homogenous eosinophilic round collagenous spheres with a cribriform pattern. The unusual finding of collagen spherules may expand the morphologic spectrum of mesothelial papillary lesions, the differential diagnosis of female pelvic peritoneal and omental epithelial and nonepithelial lesions and might cause some diagnostic confusion on small specimens. It may also shed some light on the pathophysiology and role of mesothelial and submesothelial stromal cells in the variable morphologic patterns of the stroma of papillary cores in different mesothelial lesions.

In plain English

This article is a case report about one patient. A 27-year-old woman with no history of asbestos exposure had lower abdominal pain and a large, many-chambered cystic mass in the right lower abdomen and pelvis, measuring 13.5 × 9.7 cm on imaging. The mass, the omentum (a fatty layer inside the abdomen) and the appendix were removed. Under the microscope, the mass showed multilocular peritoneal inclusion cysts, which the authors describe as a non-neoplastic lesion. The pathologists also found, by chance, a small nodule measuring 0.9 × 0.8 cm, which they diagnosed as well-differentiated papillary mesothelioma (WDPM). Most of its finger-like projections were filled with round balls of collagen, a pattern called collagenous spherulosis. The authors saw no necrosis, atypia, stromal invasion or mitotic figures. The cells stained positive for cytokeratin, calretinin and WT1. The authors ruled out malignant mesothelioma. They stated that, to their knowledge, collagenous spherulosis in WDPM had not been described before. The authors concluded that this finding widens the range of known appearances of these lesions and might cause diagnostic confusion on small specimens.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: case report (single patient)
• Who was studied: One 27-year-old nulliparous married woman with lower abdominal pain; the authors are affiliated with hospitals in Dubai, UAE
• Exposure: No asbestos exposure: the patient had no history of asbestos exposure, smoking, or alcohol intake
• Main results:
  • Imaging showed a large complex multicystic septated mass in the right iliac fossa and pelvis measuring 13.5 × 9.7 cm
  • The pelvic cystic mass was resected, along with omentectomy and appendectomy
  • An incidental small solid papillary nodule measuring 0.9 × 0.8 cm was found on microscopy
  • Most of the papillary cores of the nodule were filled with round eosinophilic spheres (collagen spherules), which were positive for Masson trichrome stain
  • No necrosis, atypia, stromal invasion, or mitotic figures were identified in the nodule
  • The cyst lining cells and the nodule cells were positive for cytokeratin, calretinin, and WT1, and negative for BerEP4 and CD31
  • The authors' diagnosis was multilocular peritoneal inclusion cysts with a nodule of WDPM; malignant mesothelioma was ruled out
  • The authors stated that, to their knowledge, collagenous spherulosis in WDPM had not previously been described or illustrated in the literature
• The authors' conclusion: The authors concluded that the finding of collagenous spherulosis in WDPM expands the range of morphologic features of papillary cores in papillary mesothelial lesions, widens the differential diagnosis of papillary lesions of the pelvic peritoneum and omentum in women, and might cause diagnostic confusion on small specimens

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma, Peritoneal mesothelioma.

Medical terms in this study, explained in our Lexicon: Well-Differentiated Papillary Mesothelioma, Reactive Mesothelial Hyperplasia, Peritoneum, Collagen, Eosinophilic, Differential Diagnosis.

Related studies

• Benign multicystic mesothelioma and peritoneal inclusion cysts: are they the same clinical and histopathological entities? A systematic review to find an evidence-based management — A.M.C. Rapisarda, A. Cianci, et al. (2018)
• Incidental finding of multiple well-differentiated papillary mesotheliomas in peritoneum — M. Jakobsen, B. Engvad, et al. (2016)
• Loose mesothelial cysts in the peritoneal cavity — Y. Ramirez, J. Rosai, et al. (2010)
• Multilocular peritoneal inclusion cyst (multicystic mesothelioma) with hyaline globules — J. Lamovec, J. Sinkovec (1996)
• Well-differentiated papillary mesothelioma of the peritoneum: a diagnostic dilemma on fine-needle aspiration cytology — J.G. Nasit, G. Dhruva (2014)
• Well-differentiated papillary mesothelioma of the female peritoneum: a clinicopathologic study of 26 cases — A. Malpica, S. Sant'Ambrogio, et al. (2012)

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