# Simultaneous Resection for Type A Thymoma With Synchronous Solitary Pulmonary Metastasis: A Case Report

## TL;DR

A patient with a rare thymoma type had a lung metastasis removed at the same time as the primary tumor, showing that even small, low-grade thymomas can spread and may benefit from combined surgery.

## Contribution

This case report presents a rare instance of simultaneous resection for type A thymoma with a solitary pulmonary metastasis.

## Key findings

- A patient with a 2.0 cm mediastinal nodule and a 0.9 cm pulmonary nodule had both resected via video-assisted thoracoscopic surgery.
- Histopathology confirmed type A thymoma with solitary pulmonary metastasis, with no recurrence after 1 year.
- The case suggests simultaneous resection can be effective for small, low-grade type A thymoma with metastasis.

## Abstract

Type A thymoma is associated with an excellent prognosis, and distant metastasis is uncommon. Optimal management for metastatic type A thymoma has not been well documented. We report a case of conventional type A thymoma with synchronous solitary pulmonary metastasis treated with simultaneous resection. An 81‐year‐old woman was incidentally found to have both a 2.0 cm anterior mediastinal nodule and a 0.9 cm pulmonary nodule in the left lower lobe. Both lesions were resected via video‐assisted thoracoscopic surgery. Histopathology and immunohistochemistry revealed identical features in both tumours, confirming type A thymoma with solitary pulmonary metastasis (pT1aN0M1b, stage IVb). No histopathological features of atypical type A thymoma were present. The patient remains recurrence‐free 1 year after surgery without adjuvant therapy. This case suggests that pulmonary metastasis can occur even in small, low‐grade type A thymoma and that simultaneous resection for diagnostic and therapeutic purposes may be considered to achieve favourable outcomes.

We report a case of conventional type A thymoma with synchronous solitary pulmonary metastasis treated with simultaneous resection. This case suggests that pulmonary metastasis can occur even in small and low‐grade type A thymoma. Simultaneous resection for diagnostic and therapeutic purposes may be considered to achieve favourable outcomes.