Nasal Fish Tank Granuloma: An Uncommon Cause for Epistaxis

An immunocompetent 28-year-old male aquarium store employee presented with 1 month of intermittent epistaxis. A bleeding granulomatous lesion was identified over the right nasal septum ( Figure 1 ). Histopathology from the incisional biopsy revealed granulomatous inflammation with the presence of acid-fast bacilli ( Figure 2 ). Culture of the homogenized specimen on Middlebrook 7H11 agar after 14 days displayed white clones of non-tuberculous Mycobacterium (NTM) that turned brilliant yellow upon light exposure ( Figure 3 ). Polymerase chain reaction (PCR) amplification of the 65-kDa heat shock protein gene with restriction enzyme analysis using Bst E II and Hae III confirmed the diagnosis of Mycobacterium marinum infection. The lesion regressed completely with 3 months of doxycycline treatment. Fish tank granuloma is a rare granulomatous skin infection caused by Mycobacterium marinum , an opportunistic NTM, commonly found in aquatic environments. 1 Extremities are most frequently affected; nasal cavity infection is seldom