Well-differentiated papillary mesothelioma

Our plain-English summary of Well-differentiated papillary mesothelioma, by K.J. Butnor, T.A. Sporn, S.P. Hammar, et al (The American Journal of Surgical Pathology, 2001).

The study

• Authors: K.J. Butnor, T.A. Sporn, S.P. Hammar, V.L. Roggli
• Journal: The American Journal of Surgical Pathology
• Published: 2001;25(10):1304-9
• Cited by: 111 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Well-differentiated papillary mesothelioma is an unusual variant of epithelial mesothelioma considered to be of low malignant potential. The majority of previously reported cases developed in the peritoneum of young women without a history of asbestos exposure. The authors report 14 cases of well-differentiated papillary mesothelioma, seven of which originated in the pleura, six in the peritoneum, and one in the tunica vaginalis. Eleven of the patients were male and three were female, with an average age at presentation of 58 years (range 32-82 years). Six of the patients had a quantifiable history of asbestos exposure. Of the nine cases with complete follow-up, six had clinically indolent disease, one showed resolution after adjuvant chemotherapy, one pursued an aggressive course, and one died of other causes. These findings indicate that well-differentiated papillary mesothelioma is a rare variant of mesothelioma with a variable clinical prognosis that is etiologically related to asbestos exposure in some cases.

In plain English

This article was a case series describing 14 cases of well-differentiated papillary mesothelioma, an unusual form of epithelial mesothelioma, taken from the consultation files of two of the authors. Seven tumors arose in the pleura, six in the peritoneum and one in the tunica vaginalis. Eleven patients were men and three were women, aged 32 to 82 years (mean 58). Asbestos history was available for 12 patients. Nine had worked in jobs with a high likelihood of asbestos exposure, and for three the only known exposure was contact with a household member exposed at work. Pleural plaques were confirmed in three cases. One patient's lung tissue contained 2000 asbestos bodies per gram of wet lung, compared with the laboratory's normal value of 0 to 20. The article did not name fiber types. Of nine cases with complete follow-up, six had clinically indolent disease, one resolved after chemotherapy, one followed an aggressive course and one died of other causes. The authors concluded that this tumor has variable clinical behavior and appears to be associated with asbestos exposure in at least some cases.

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 series: review of 14 pathology consultation cases, with medical records, slides, immunohistochemistry, electron microscopy in two cases and asbestos body counting in one case
• Who was studied: 14 patients with well-differentiated papillary mesothelioma (7 pleural, 6 peritoneal, 1 tunica vaginalis) from the consultation files of two of the authors (Duke University Medical Center, Durham, North Carolina, and Diagnostic Specialties Laboratory, Bremerton, Washington). There were 11 men and 3 women, aged 32 to 82 years. No study period is given.
• Exposure: Asbestos exposure assessed from medical records. Occupational exposure applied to nine patients (jobs listed include insulator, power plant, machinist, rigger, furnace worker, Merchant Marine, railroad machinist, shipyard welder, maintenance worker). Household contact with an occupationally exposed person was the only known exposure for three patients. Exposure could not be determined for two. No fiber types were named.
• Main results:
  • Of the 14 patients, 11 were male and 3 female, with an average age at presentation of 58 years (range 32 to 82 years).
  • In three cases, contact with an occupationally exposed household member was the only known asbestos exposure.
  • Exposure duration was known in six cases (four occupational, two household contacts) and ranged from 2.5 to 35 years (mean 21 years).
  • Pleural plaques were seen on imaging and confirmed under the microscope in three cases (case nos. 1, 11 and 14), including one household contact.
  • In case no. 10, a shipyard welder with peritoneal tumor, lung tissue contained 2000 asbestos bodies per gram of wet lung tissue. The authors' normal value is 0 to 20.
  • Of nine cases with complete follow-up: six had clinically indolent disease, one showed resolution after adjuvant chemotherapy, one pursued an aggressive course, and one died of other causes.
  • Two cases showed focal areas of invasion into the underlying tissue (stroma).
  • On immunohistochemistry, all nine tumors tested stained strongly for cytokeratin, and six of six tested stained for calretinin.
• The authors' conclusion: The authors concluded that well-differentiated papillary mesothelioma is a variant of mesothelioma with variable clinical behavior. It occurs in both men and women and in the peritoneum, pleura and tunica vaginalis, and appears to be associated with asbestos exposure in at least some cases.
• Limitations the authors state:
  • Follow-up for the two cases with focal invasion was relatively short.
  • The role of chemotherapy needs further study, given the mixed responses in this series.
  • Telling this tumor apart from diffuse malignant mesothelioma with a papillary pattern can be difficult, especially in small biopsies.

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, Mesothelioma, Peritoneum, Asbestos Exposure, Pleura, Tunica Vaginalis, Chemotherapy, Prognosis.

Related studies

• Well-differentiated papillary mesothelioma: a clinicopathological and immunohistochemical study of 18 cases with additional observation — X. Chen, W. Sheng, et al. (2013)
• Case Report of a Well-Differentiated Papillary Mesothelioma of the Tunica Vaginalis in an Undescended Testis With Review of Literature — P. Parcesepe, S. Sina, et al. (2016)
• Well differentiated (benign) papillary mesothelioma of the tunica vaginalis — R. Chetty (1992)
• Well-Differentiated Papillary Mesothelioma of the Tunica Vaginalis: Case Report and Systematic Review of Literature — W.K. Tan, M.Y. Tan, et al. (2016)
• Well-differentiated Papillary Mesothelioma of the Tunica Vaginalis — W.K. Tan, M.Y. Tan, et al. (2016)
• Well-differentiated papillary mesothelioma of tunica vaginalis testis of unknown malignant potential: Sonographic appearance — K.W.S. Ko, K.S. Tse, et al. (2018)

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