# A Fishy Situation: Hand Infection due to Mycobacterium marinum Mistaken for Giant Cell Tumor

## TL;DR

A case of Mycobacterium marinum infection was initially mistaken for a giant cell tumor, highlighting the importance of proper diagnostic testing.

## Contribution

The paper highlights the diagnostic challenge of M. marinum and the usefulness of QuantiFERON Gold testing in confirming the infection.

## Key findings

- M. marinum infection can mimic noninfectious orthopedic conditions like giant cell tumors.
- QuantiFERON Gold testing can provide supportive evidence for diagnosing M. marinum.

## Abstract

Mycobacterium marinum is an acid‐fast bacterium (AFB) associated with exposure to water and aquatic species. When inoculated, infection can result in nodular cutaneous lesions. In the absence of detailed history or culture data, these nodular skin lesions can be mistaken for noninfectious orthopedic conditions. We present a case of M. marinum mistaken for a giant cell tumor. This case illustrates the overlap in these conditions, as well as the utility of QuantiFERON Gold testing to provide supportive evidence for the diagnosis of Mycobacterium marinum.