Well-differentiated papillary mesothelioma of the peritoneum: a diagnostic dilemma on fine-needle aspiration cytology

Our plain-English summary of Well-differentiated papillary mesothelioma of the peritoneum: a diagnostic dilemma on fine-needle aspiration cytology, by J.G. Nasit, G. Dhruva (American Journal of Clinical Pathology, 2014).

The study

• Authors: J.G. Nasit, G. Dhruva
• Journal: American Journal of Clinical Pathology
• Published: 2014;142(2):233-42
• Type of article: Case report, Review
• Cited by: 12 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Objectives: Well-differentiated papillary mesothelioma of the peritoneum (WDPMP) is an uncommon subtype of epithelioid mesothelioma. Usually, WDPMP has a benign course, while a few patients have multiple recurrence and malignant transformation on long-term follow-up. The histology of WDPMP has been well studied compared with the cytology. Although accurate diagnosis is based only on histology and immunohistochemical stains, knowledge of the cytologic features of WDPMP in context with clinical and radiologic features is essential to predict a preoperative diagnosis and guide proper management, after excluding reactive mesothelial hyperplasia, malignant mesothelioma, and serous neoplasms of the ovaries and peritoneum. Surgical excision gives a favorable outcome.

Methods: We describe a case of 28-year-old woman who sought treatment for chronic lower abdominal pain, dysuria, and dyspareunia.

Results: Radiologic findings suggested multiple metastatic peritoneal deposits. Ultrasound-guided fine-needle aspiration cytology showed many papillae, tubulopapillary and spheroid groups, monolayered pavement-like sheets, and many dispersed cells. Papillae showed many layers of round to ovoid cells, with minimal atypia. Atypical mitoses and necrosis were not found. A cytologic diagnosis of WDPMP was suggested. After complete resection of all the tumor nodules, histopathology and immunohistochemical findings were compatible with WDPMP. On follow-up, she developed tumor recurrence at 9 months and was managed successfully with adjuvant chemotherapy.

Conclusions: This article highlights the cytologic features of WDPMP with relevant review of the literature and differential diagnosis.

Copyright© by the American Society for Clinical Pathology.

In plain English

This case report, from a pathology department in Gujarat, India, described a 28-year-old woman with well-differentiated papillary mesothelioma of the peritoneum (WDPMP), a rare subtype of epithelioid mesothelioma. She had lower abdominal pain for 5 years and no history of asbestos exposure. A CT scan showed many solid-cystic masses in the peritoneum and on the bladder surface, which radiology suggested were metastases from an unknown cancer. A fine-needle aspiration sample showed bland cells with minimal atypia and no atypical mitoses or necrosis, and the cytology suggested WDPMP. All tumor nodules were surgically removed; the largest measured 7.8 × 7.1 × 5.9 cm. Tissue examination and immunohistochemistry confirmed WDPMP. Two recurrent peritoneal nodules appeared at 9 months and were managed with intravenous cisplatin and doxorubicin. The authors compared the case with nine earlier reports on WDPMP cytology. They concluded that WDPMP has benign or at most low malignant potential, and that histology and immunohistochemistry are sometimes needed for accurate diagnosis.

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 of one patient, with a review of earlier published case reports of the cytology of well-differentiated papillary mesothelioma of the peritoneum
• Who was studied: one 28-year-old woman seen at a government medical college and hospital in Gujarat, India; dates not given
• Exposure: No asbestos exposure: the patient had no history of asbestos exposure. No fiber type or exposure was studied.
• Main results:
  • A CT scan of the patient showed many solid-cystic masses in the peritoneum and on the surface of the urinary bladder, and radiology suggested metastatic deposits from an unknown primary cancer.
  • In the patient's fine-needle aspiration smears, atypical mitoses, psammoma bodies and necrosis were not seen. Taken together with the clinical history and radiology, the cytology suggested WDPMP.
  • At surgery, all of the patient's tumor nodules were removed. The largest nodule measured 7.8 × 7.1 × 5.9 cm and the smallest 1.0 × 1.0 × 0.8 cm.
  • On immunohistochemistry, the patient's tumor cells stained strongly for calretinin and were positive for mesothelin, EMA and pancytokeratin. They were negative for cytokeratin 5/6, 7 and 20, Ber-EP4, CEA, estrogen receptor and progesterone receptor. These findings confirmed WDPMP.
  • The patient had a tumor recurrence of two nodules in the peritoneum at 9 months after surgery.
  • The patient's recurrence was treated with intravenous cisplatin and doxorubicin, which the authors described as successful management.
  • In the authors' comparison with previously reported cases, papillae and tubulopapillary fragments with mild atypia were found in all cases, including this patient's.
• The authors' conclusion: The authors concluded that WDPMP is a rare neoplasm of benign or at most low malignant potential. They wrote that cytology, in context with clinical and radiologic features, can suggest the diagnosis, but that histology and immunohistochemistry are sometimes required for accurate diagnosis and to guide management.

Topics

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

Medical terms in this study, explained in our Lexicon: Well-Differentiated Papillary Mesothelioma, Peritoneum, Fine-Needle Aspiration, Cytology, Epithelioid, Mesothelioma, Malignant Transformation, Histology.

Related studies

• Fine needle aspiration cytology of well-differentiated papillary mesothelioma: a case report — Y. Gong, R. Ren, et al. (2005)
• Fine-needle aspiration of a well-differentiated papillary mesothelioma in the inguinal hernia sac: A case report and review of literature — Y.Y. Wheeler, F. Burroughs, et al. (2009)
• Incidental finding of multiple well-differentiated papillary mesotheliomas in peritoneum — M. Jakobsen, B. Engvad, et al. (2016)
• Aberrant Pax-8 expression in well-differentiated papillary mesothelioma and malignant mesothelioma of the peritoneum: a clinicopathologic study — D. Xing, N. Banet, et al. (2018)
• Malignant biphasic peritoneal mesothelioma in a child: fine-needle aspiration cytology, histopathology, and immunohistochemical features along with review of literature — S.K. Arora, R. Srinivasan, et al. (2012)
• Collagenous Spherulosis in Well-Differentiated Papillary Mesothelioma in a Female With Multilocular Peritoneal Inclusion Cysts — B. AbdullGaffar, L.G. Raman (2019)

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