# A Unique Case of Cellulitis Secondary to Mycobacterium chelonae in a Patient With Monoclonal Gammopathy of Undetermined Significance

## TL;DR

An 84-year-old patient with MGUS developed a rare Mycobacterium chelonae infection, highlighting the importance of early specialist involvement in such cases.

## Contribution

This case report emphasizes the correlation between MGUS and mycobacterial infections, advocating for early specialist consultation.

## Key findings

- MGUS can impair both humoral and cellular immunity, increasing infection risk.
- Mycobacterium chelonae infections may be atypical in MGUS patients.
- Delayed diagnosis underscores the need for early specialist involvement.

## Abstract

We report a case of an 84-year-old patient with Monoclonal Gammopathy of Undetermined Significance (MGUS) treated with multiple courses of antibiotics and steroids before being diagnosed with Mycobacterium chelonae infection. It is known that MGUS affects both humoral and cellular immunity with impairment of antibody production, function of T-cells, natural killer (NK) cells, and dendritic cells. This case report demonstrates the need to consider patients with MGUS as immunocompromised and draws attention to the correlation between MGUS and Mycobacterium infections. The delay in diagnosis exemplifies the importance of considering atypical pathogens and involving sub-specialists early in the treatment of infections in patients with a history of MGUS.