# A case report of typical well-differentiated papillary mesothelial tumor diagnosed by internal thoracoscopy and literature review

## TL;DR

A rare benign pleural tumor was diagnosed in a patient with long-term pleural effusions using internal thoracoscopy, highlighting its usefulness for difficult cases.

## Contribution

Demonstrates the effectiveness of internal thoracoscopy in diagnosing minimal pleural lesions not visible on CT scans.

## Key findings

- Internal thoracoscopy successfully diagnosed a well-differentiated papillary mesothelial tumor in a patient with recurrent pleural effusions.
- The tumor was benign and preinvasive, with a long clinical history of over 35 years.
- CT scans failed to detect the minimal lesion, emphasizing the need for alternative diagnostic methods.

## Abstract

We report a case of well-differentiated papillary mesothelial tumor (WDPMT) diagnosed using internal thoracoscopic biopsy in a patient who has suffered from recurrent pleural effusions for over 35 years together with a history of elevated CA125. We hope to provide a case for the diagnosis of this rare benign and preinvasive pleural tumor and recommend that internal thoracoscopy may be a good choice in these recurrent pleural effusion patients especially for those minimal lesions not easily detected using CT scan.