# Primary Mediastinal Malignant Melanoma Presenting With Pleural Effusion: A Case Report

## TL;DR

A rare case of primary mediastinal melanoma initially showed as pleural effusion, highlighting the need for early diagnosis and intervention.

## Contribution

Reports a rare case of PMMM presenting with pleural effusion and emphasizes the importance of pathological diagnosis.

## Key findings

- PMMM can present with pleural effusion as the initial symptom, making diagnosis challenging.
- Pleural hemorrhage may be a characteristic feature of pleural metastasis in PMMM.
- Prognosis for PMMM with pleural effusion is poor despite temporary interventions.

## Abstract

Primary mediastinal malignant melanoma (PMMM) presenting with pleural effusion as the initial manifestation is exceedingly rare, presenting significant diagnostic and therapeutic challenges. This article reports a case of PMMM that initially manifested as pleural effusion and includes a review of the relevant literature.

The patient was admitted with pleural effusion and an anterior mediastinal mass. A pleural biopsy and fine‐needle aspiration of the mediastinal mass led to a pathological diagnosis of malignant melanoma. Ultimately, based on clinical findings, a final diagnosis of PMMM was established. The patient subsequently developed pleural hemorrhage; although hemostasis was achieved through thoracoscopy, his condition stabilized only temporarily. He ultimately succumbed to lung infection and multiple organ failure.

PMMM presenting with pleural effusion lacks distinct clinical features, highlighting the importance of pathological diagnosis. Pleural hemorrhage associated with pleural metastasis may be a characteristic feature, and the prognosis for such cases is poor. Enhanced recognition and early intervention are essential to improve outcomes.