Prepubertal gynecomastia following topical inunction of estrogen containing ointment

A six and a half-year-old boy was investigated for prepubertal gynecomastia and hyperpigmentation of the skin. The biological, clinical and radiological work-up did not reveal any endocrinological or tumoral cause. It was incidentally noticed that the patient's sister presented with similar clinical signs which could be related to an estrogen containing ointment. Long-term follow-up of the boy showed complete but delayed regression of the gynecomastia and persistence of hyperpigmentation. His sister developed later on a normal puberty.