Rationale: Mammary hamartoma is a rare benign breast tumor, composed of ducts, lobules, fibers, and adipose tissue. We describe a mammary hamartoma in a man; this is the fourth case being reported in the literature.
Patient concerns: A 30-year-old man presented with a 1-month history of a painless mass in his right breast.
Diagnosis: Ultrasound imaging and mammography revealed a lesion, approximately 2.0 cm × 2.0 cm in size, in the right breast, which was considered to be either a lipomyoma or an adenoma fibrosum.
Interventions: The mass was surgically resected. Pathological examination confirmed the diagnosis of mammary hamartoma.
Outcomes: The patient was discharged from the hospital after surgery. There was no sign of reoccurrence during a 1-year follow-up period.
Lessons: At present, mammary hamartoma is considered to be a benign lesion, usually treated by surgical resection. Some reports have suggested a possible association between a hamartoma and the development of breast malignancy. The pathology and biology of an association between a mammary hamartoma and malignancy have not been defined to date.