Gynecomastia was bilateral in five of seven prepubertal boys. Onset was between 2½ and 7½ years of age in five patients and was present from birth in another. Urinary estrogen excretion was increased in two patients. In six patients the condition was selflimited; one boy required mastectomy and the histopathological picture was that of dense fibrocollagenous and adipose stromacontaining ducts. In two instances, there was a family history of the condition in males.
Latorre H, Kenny FM. Idiopathic Gynecomastia in Seven Preadolescent BoysElevation of Urinary Estrogen Excretion in Two Cases. Am J Dis Child. 1973;126(6):771–773. doi:10.1001/archpedi.1973.02110190621006