Iatrogenic infection by atypical mycobacteria: a case report of M. phlei infection in an immunocompetent patient simulating breast malignancy.

Introduction: Atypical nontuberculous mycobacteria (NTM) constitute a diverse group of environmental organisms capable of causing infections in immunocompromised patients. Mycobacterium phlei has limited documentation of clinical disease in the literature.

Case presentation: We present the case of a 68-year-old immunocompetent female with type II diabetes mellitus and a recent history of laparoscopic cholecystectomy. One month postoperatively, the patient developed localized wound complications followed by the appearance of a growing axillary mass. Imaging studies suggested possible malignancy (BIRADS-4), but histopathological evaluation revealed chronic granulomatous inflammation without malignant cells.

Results: the diagnosis was a rare case of lymphadenitis due to M. phlei, confirmed by histology and molecular diagnostics. The patient responded favorably to combination antibiotic therapy.

Conclusions: Through this report, we share our experience and expand the understanding of this entity, emphasizing the importance of considering this differential diagnosis and establishing appropriate guidelines for therapeutic decision-making, emphasizing in NTM.