Atypical Mycobacteria Infection Mimicking Cutaneous Sarcoidosis

Figure 1: (A) x86 H&E. Us-guided biopsy shows ill-defined non-necrotising granul omatous inflammation. (B) x220 H&E and (c) x350 H&E. Higher power highlights the extensive neutrophils and lymphocytes in between granul omatous inflammation. (D) x440 Ziehl-Nielson. Special staining reveals abundant axid-fast bacilli

Teaching Point

This case demonstrates a cutaneous atypical mycobacterial infection arising in a medically immunosuppressed patient. The histological differential included cutaneous sarcoidosis, given the patients history. However, there were sufficient features to suggest that cutaneous sarcoidosis was unlikely, and that an infectious aetiology was more likely. In particular,

• The granulomas in sarcoidosis are typically well-defined and exhibit less intervening inflammation (‘naked granulomas’). The extensive inflammation led us to investigate an infectious cause and request special stains.
• Tuberculosis generally shows few bacilli on Ziehl-Nielsen staining, but the abundant microorganisms observed here suggest an atypical mycobacterial infection and therefore prompted PCR testing. This confirmed infection with M.Avium, which is found in the environment and can cause opportunistic infections in immunocompromised patients.

Conflict of Interest Statement: there is no conflict of interest to declare from any author.

Statement of funding sources: there are no funding sources to declare.