Abstract
INTRODUCTION: Gynecomastia is a benign proliferation of the glandular tissue of the breast in males. Depending on the age, it can be considered a physiological condition. Prepubertal unilateral gynecomastia is a rare phenomenon. There are only a few case reports described through the last few years. CASE PRESENTATION: We report the clinical appearance and management of prepubertal idiopathic unilateral gynecomastia in a 9-year-old boy. We further include a literature review of 14 cases from 2011 to 2021. In contrast to pubertal gynecomastia, prepubertal gynecomastia and especially unilateral prepubertal gynecomastia are extremely rare conditions. Most cases remain idiopathic. CONCLUSION: Chromosomal and genetic testing, as well as oncological, endocrine diagnostic and tests for liver and kidney function should be performed. In case of idiopathic prepubertal gynecomastia, surgery is an important part of therapy since patients suffer from their atypical and rare phenotype.