A 37-year-old female presents to her OBGYN with left breast pain. The patient complains of a new palpable lump located on the upper, outer quadrant of her left breast for 2 weeks. The lump is painful and erythematous. She denies nipple discharge and has no history of nipple piercing. She has never smoked and stopped breastfeeding 3 months ago. She has no personal history of breast cancer or family history of breast cancer.

The patient undergoes a left breast ultrasound which reveals a 4.5 cm mass at 10 o’clock, anterior depth 1.5 cm from the nipple. An ultrasound-guided biopsy was sent to surgical pathology for histologic evaluation, and a sterile aspirate was sent to the clinical microbiology laboratory for Gram stain and culture. A Gram stain revealed few gram-positive bacilli, which were consistent with coryneform bacteria. After 48 hours of incubation, a blood agar plate revealed growth of non-hemolytic, round, gray-to-white colonies measuring less than 1 mm in diameter. Species level identification was confirmed by the Bruker Biotyper MADI-TOF mass spectrometry. 

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Author Information

Bethany Burns, D.O., Anatomic and Clinical Pathology Resident, PGY3, Cleveland Clinic
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