Well-Differentiated Papillary Mesothelial Tumor of the Scrotum with Suspicious Invasion

Our plain-English summary of Well-Differentiated Papillary Mesothelial Tumor of the Scrotum with Suspicious Invasion, by S. Im, J.M. Yoo, U. Cho (Diagnostics, 2024).

The study

• Authors: S. Im, J.M. Yoo, U. Cho
• Journal: Diagnostics
• Published: 2024;14(2)
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Well-differentiated papillary mesothelial tumor (WDPMT) is a distinct form of mesothelioma with low malignant potential and is mostly found in the peritoneal cavity. It consists of mesothelial cells with papillary structure and bland cytology. We report a rare case of WDPMT with suspicious invasive foci in the tunica vaginalis. WDPMT with invasive foci is known to have a tendency for recurrence. Therefore, careful attention should be given to properly diagnosing and treating this rare entity.

In plain English

This article is a case report describing one patient. A 22-year-old man had swelling in the left scrotum that kept returning despite several attempts to drain fluid. Ultrasound showed a 2.2 × 1.5 cm mass inside a fluid-filled sac (hydrocele), and the sac was surgically removed. Under the microscope, the mass, in the tunica vaginalis (the lining around the testis), was made of finger-like (papillary) growths covered by a single layer of uniform mesothelial cells. Multiple small clusters of glands in the sac wall were judged suspicious for invasion, although these cells looked only mildly abnormal and were not dividing. Staining showed a mesothelial marker in both the main mass and the small glands. Genetic testing found no significant harmful mutations, but the test panel did not include two genes linked to this tumor in other reports. The diagnosis was well-differentiated papillary mesothelial tumor with suspicious invasive foci. The man received no further treatment and had no recurrence after 48 months. The authors concluded that focal or minimal invasion can still fit this diagnosis and may behave indolently. The article does not mention asbestos.

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: Single case report (short image-based article)
• Who was studied: One 22-year-old man with swelling of the left scrotum, treated at St. Vincent's Hospital, The Catholic University of Korea, Seoul
• Exposure: Not reported: the article does not mention asbestos or any other exposure history for the patient
• Main results:
  • In this patient, ultrasound showed a mass measuring 2.2 × 1.5 cm within the hydrocele sac
  • The papillary mass was lined by a single layer of uniform cuboidal mesothelial cells
  • Multiple suspicious invasive foci (small glands) were found along the wall of the sac
  • The small glands in the sac wall showed mild cytologic atypia and no mitotic activity
  • The mesothelial marker WT-1 was positive in both the main papillary mass and the small glands. The tumor cells were negative for CEA, cytokeratin 20, EMA and MOC-31
  • Next-generation sequencing found no significant pathogenic mutations, including no BAP1 mutation, CDKN2A homozygous deletion or BRAF p.V600E mutation
  • The final diagnosis was well-differentiated papillary mesothelial tumor with suspicious invasive foci
  • The patient received no adjuvant therapy and had no recurrence after 48 months of follow-up
• The authors' conclusion: The authors concluded that their case adds evidence that focal or minimal invasion in a well-differentiated papillary mesothelial tumor can still merit that diagnosis and may show indolent behavior
• Limitations the authors state:
  • The genetic test panel did not include TRAF7 and CDC42, genes reported in this tumor type in the peritoneum
  • Because few cases have been reported, the clinical course of this tumor with suspicious invasion is hard to understand

Topics

Medical terms in this study, explained in our Lexicon: Well-Differentiated, Mesothelioma, Peritoneal Cavity, Mesothelial Cells, Cytology, Tunica Vaginalis.

Related studies

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• Well-differentiated papillary mesothelial tumor of the peritoneum in a young woman: A case report with molecular insights — R. Xu, S. Xu, et al. (2025)
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• Simultaneous Occurrence of Well-Differentiated Papillary Mesothelial Tumor and Multicystic Mesothelioma — D. Miličić, S. Tomić, et al. (2026)
• A case of well-differentiated papillary mesothelial tumor concomitant with primary gastric cancer: case report and literature review — G. Wang, P. Wang, et al. (2026)

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