Idiopathic prepubertal unilateral gynecomastia

Rationale Prepubertal unilateral gynecomastia is extremely rare, whose etiology and management strategy are not familiar. We would like to present a case and a literature review of unilateral prepubertal gynecomastia. Patient concerns A 11-year old male patient with complaints of unilateral enlargement of breast tissue presented in our clinic, whose physical examination, biochemical, hormonal and oncologic findings were normal. Diagnoses This patient was diagnosed as idiopathic unilateral prepubertal gynecomastia (IUPG) and self-abasement, social isolation and sensitive of interpersonal relationship. Interventions The patient received subcutaneous mastectomy. Histopathological examinations showed idiopathic gynecomastia of ductal epithelial hyperplasia and active interstitial fibrous hyperplasia, with no evidence of any pathological finding. Immunohistochemical examination showed estrogen receptor (ER)-α positive (70%), epidermal growth factor receptor (EGFR) positive, Her-2 positive (1+), Progesterone Receptor (PR) positive (80%). Outcomes A remarkable improvement was observed both in the physical and mental conditions at the post-surgical 6-month follow-up visit, showing no evidence of recurrence. Lessons Further investigation is needed to clarify the pathogenesis of IUPG. All patients with IUPG should have a full endocrine and oncologic evaluation, and surgical excision may be the individually designed for each patient with the help of MRI of breast.