Well-differentiated papillary mesothelioma of the female peritoneum: a clinicopathologic study of 26 cases

Our plain-English summary of Well-differentiated papillary mesothelioma of the female peritoneum: a clinicopathologic study of 26 cases, by A. Malpica, S. Sant'Ambrogio, M.T. Deavers, et al (The American Journal of Surgical Pathology, 2012).

The study

• Authors: A. Malpica, S. Sant'Ambrogio, M.T. Deavers, E.G. Silva
• Journal: The American Journal of Surgical Pathology
• Published: 2012;36(1):117-27
• Cited by: 72 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Well-differentiated papillary mesothelioma (WDPM) is an uncommon mesothelial tumor that occurs in the peritoneum of women over a wide age range. Although considered a tumor of uncertain malignant potential, information about its biological behavior is still limited. In this study, we present the clinicopathologic features of 26 cases of WDPM of the female peritoneum seen in our institution over a 20-year period (1990 to 2010). Clinical information and pathology material were reviewed in all cases. Patients ranged in age from 23 to 75 years (median, 47 y; mean, 48.6 y). There was no history of asbestos exposure in any of our cases. Ten patients had undergone surgery previously, and 6 had a history of endometriosis. In 24 patients, the WDPM was an incidental finding during surgery for a benign or malignant lesion. Only 2 patients presented with symptoms: 1 with an acute abdomen and the other with chronic pelvic pain. The former had developed a small hemoperitoneum because of bleeding of 1 of the lesions of WDPM, whereas the latter had a 2-cm WDPM involving the distal fallopian tube. The lesions were single or multiple (13 cases each) and ranged in size from 0.1 cm to 2 cm. The following sites were involved: abdominal or pelvic peritoneum not otherwise specified (10 cases), omentum (7 cases), cul-de-sac (6 cases), colonic serosa (4 cases), small bowel mesentery (2 cases), uterine serosa (2 cases), stomach serosa (1 case), large bowel mesentery (1 case), fallopian tube (1 case), ovary (1 case), and inguinal hernia (1 case). In all cases the lesions were excised. Microscopically, all of our cases had the typical features described for WDPM (ie, a papillary architecture that may be accompanied by glandular/tubular patterns, nests of cells and individual cells, bland mesothelial cells, absent or rare mitotic figures). The initial diagnosis in our cases was variable, including WDPM, mesothelial hyperplasia, malignant mesothelioma, serous tumor of low malignant potential of the peritoneum, papillary endosalpingiosis, and chronic xanthogranulomatous salpingiosis. Follow-up was obtained for 25 patients, and it ranged from 4 to 192 months (mean, 47.5 mo; median, 32 mo); 22 patients are alive with no evidence of WDPM after a follow-up that ranged from 5 to 144 months. One of these patients experienced recurrence of WDPM 46.5 months after initial diagnosis. In this patient, WDPM was an incidental finding during a total abdominal hysterectomy and bilateral salpingo-oophorectomy for serous cystadenofibroma. The recurrence was also an incidental finding during a colectomy for colonic adenocarcinoma. This patient is alive with no other recurrences 73 months after initial diagnosis and 36 months after diagnosis of the recurrence. Three patients died of other causes: pancreatic cancer at 4 months and 12 months and leukemia at 192 months. Recognition of the histologic features of WDPM and proper clinical correlation allow for the correct diagnosis of this entity. If necessary, immunohistochemical studies such as calretinin and keratin 5/6 facilitate the recognition of the mesothelial nature of this neoplasm. Although no patient died of disease in this series, follow-up of patients with this diagnosis is warranted on the basis of possible recurrences or misdiagnosis of an undersampled malignant mesothelioma.

In plain English

This study described 26 women with well-differentiated papillary mesothelioma (WDPM) of the peritoneum, the abdominal lining, from the pathology files of The University of Texas M.D. Anderson Cancer Center, 1990 to 2010. Patients were aged 23 to 75 years. No history of asbestos exposure was found in the 25 cases with clinical information available. In 24 women the tumor was found by chance during surgery for another condition; 1 woman had an acute abdomen and 1 had chronic pelvic pain. All lesions were removed. In the 25 cases with a recorded size, they measured 0.1 to 2 cm. Follow-up, available for 25 patients, ranged from 4 to 192 months. Twenty-two were alive with no evidence of WDPM; one of them had had a recurrence at 46.5 months. Three died of other causes (pancreatic cancer in 2, leukemia in 1). The authors found no definitive invasion, although in one case rare tubular structures very focally (less than 0.5 mm) involved the superficial ovarian cortex. The authors concluded that WDPM should be considered a tumor of uncertain malignant potential requiring follow-up.

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: Retrospective clinicopathologic case series from one institution's pathology files
• Who was studied: 26 women with WDPM of the peritoneum, from the Department of Pathology at The University of Texas M.D. Anderson Cancer Center, 1990 to 2010. Twenty cases were sent in for consultation and 6 were from the hospital itself. Ages were 23 to 75 years (median 47, mean 48.6). Seven cases first diagnosed as WDPM were excluded because they turned out to be undersampled malignant mesotheliomas or localized mesotheliomas.
• Exposure: History of asbestos exposure was recorded. None was found in the 25 cases with available clinical information. No fiber types or doses were studied.
• Main results:
  • In 24 of 26 cases the tumor was an incidental finding during surgery for other conditions (13 benign conditions, 11 malignant or benign tumors).
  • Two patients had symptoms: 1 had an acute abdomen and 1 had chronic pelvic pain and menorrhagia.
  • Lesions were single in 13 cases and multiple in 13 cases.
  • Lesion size was known in 25 cases and ranged from 0.1 to 2 cm. One case was described only as 'small nodules', with no measurement.
  • Follow-up was obtained for 25 cases and ranged from 4 to 192 months (mean 47.5, median 32).
  • 22 patients were alive with no evidence of WDPM after 5 to 144 months of follow-up.
  • One of these 22 patients had a recurrence of WDPM 46.5 months after the first diagnosis.
  • Three patients died of other causes: 2 of pancreatic cancer (at 4 and 12 months) and 1 of leukemia (at 192 months).
  • The authors found no definitive invasion into adjacent structures or tissues.
  • In one case (case 14), rare tubular structures very focally involved the superficial ovarian cortex, over less than 0.5 mm. The authors noted that other investigators have called this finding 'seedling'. This patient had no recurrence after 192 months of follow-up.
  • The tumor cells stained positive for calretinin in 11 of 11 cases tested and for keratin 5/6 in 2 of 3 cases tested.
  • The first diagnosis was WDPM in 15 cases. Other cases were first diagnosed as conditions including mesothelial hyperplasia, benign mesothelioma, malignant mesothelioma and papillary endosalpingiosis.
• The authors' conclusion: The authors concluded that WDPM should currently be considered a tumor of uncertain malignant potential requiring follow-up. They also concluded that adequate sampling, including underlying normal tissue, and clinical correlation are needed to rule out an undersampled malignant mesothelioma.
• Limitations the authors state:
  • The lesion that bled and caused the acute abdomen in one patient was not available for the authors' review.
  • The authors stated that further studies with adequate clinicopathologic information are needed to determine how often WDPM recurs and whether its alleged risk of turning into malignant mesothelioma is real.

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, Peritoneum, Pathology, Asbestos Exposure, Omentum, Small Bowel Mesentery, Mesentery, Inguinal Hernia.

Related studies

• Therapeutic strategies for well-differentiated papillary mesothelioma of the peritoneum — Y.K. Lee, H.J. Jun, et al. (2013)
• Value of mesothelial and epithelial antibodies in distinguishing diffuse peritoneal mesothelioma in females from serous papillary carcinoma of the ovary and peritoneum — R.L. Attanoos, R. Webb, et al. (2002)
• 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)
• Collagenous Spherulosis in Well-Differentiated Papillary Mesothelioma in a Female With Multilocular Peritoneal Inclusion Cysts — B. AbdullGaffar, L.G. Raman (2019)
• Well-differentiated papillary mesothelioma in the pelvic cavity. A case report — T. Haba, K. Wakasa, et al. (2003)
• Well-differentiated papillary mesothelioma of the peritoneum is genetically defined by mutually exclusive mutations in TRAF7 and CDC42 — M. Stevers, J.T. Rabban, et al. (2019)

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