Vacuoles in the Breast: A Histologic Clue for an Unusual Presentation of an Atypical Organism

Abstract

Infections with nontuberculous mycobacteria (NTM) are increasing in prevalence worldwide, and this group of organisms is emerging as significant clinical pathogens. We present a case of a 58-year-old female with persistent furuncles of the breast who was found to have an NTM infection. This case is unique for the lack of risk factors for NTM in the patient's history, the location of the infection in the breast, and the close cooperation needed across disciplines to arrive at the diagnosis. This multi-disciplinary discussion considers the classic clinical presentation of NTM, it is a characteristic morphological appearance on histopathology, the differential diagnosis, treatment, and the ultimate outcome of the case. This case report and discussion will assist both clinicians and pathologists in the diagnosis of this important infectious disease.

Keywords: breast abscess; breast pathology; clinical microbiology; emerging pathogen; histopathologic examination; histopathology (hp); interdisciplinary health team; non-tuberculosis mycobacteria.

Figure 1. Right breast lesion.

Photographs of the patient’s lesions on the right breast (A) and (B) at initial presentation. Image from the patient’s initial mammogram demonstrating a focal asymmetry in the right upper outer quadrant. This finding correlates with the palpable area of concern. Note the skin thickening associated with focal asymmetry (C).

Figure 2. Histopathologic examination of excisional biopsy.

Surgical excision of lesion at the upper outer quadrant of the right breast. (A) Granulomatous inflammation with epithelioid histiocyte, multinucleated giant cells (red arrow), lymphocytes, and plasma cells (H&E, ×400). (B) Lipid-like vacuoles (red arrow) seen in the background of acute inflammation (H&E, ×400). (C) Clumps of intravacuolar acid-fast bacilli (red arrow, AFB stain, 600). (D) FITE stain highlights acid-fast microorganisms (red arrow, FITE stain, 600).