Pilonidal sinus involving the breast in a man: A case report and literature review

RATIONALE: Pilonidal sinus disease (PSD) involving the breast is extremely rare and has not been described in man. PATIENT CONCERNS: This current case report presents a case of a pilonidal cyst in a 46-year-old man which was surgically treated. He had intermittent pain in his left breast for 2 months and came for local rupture and discharge for 1 week. DIAGNOSIS: The initial diagnosis is male mastitis, on the basis of the histological features of H&E-stained specimens and immunohistochemistry of the resected lump, this case was diagnosed as PSD. INTERVENTIONS: The patient underwent “enlarged resection of the left breast lesion” under local anesthesia. OUTCOMES: The patient's surgical area healed well, without any signs of recurrence. CONCLUSION: PSD involving the breast is extremely rare in man, with no typically clinical manifestations, and could be easily ignored. This disease requires great attentions from clinicians.