A 7-year-old boy who presented with a painful left hemi-scrotal mass w
as diagnosed with acquired lymphangioma or the scrotum. Chronic fricti
on from a cast for Perthes' disease might have been the cause of sudde
n enlargement of a congenital lymphangioma of the scrotum. Magnetic re
sonance imaging (MRI) was useful for preoperative diagnosis and determ
ining the extent of the scrotal lesions. Total excision of the mass le
aving the overlying skin was successfully performed. The clinical sign
ificance of MRI for preoperative diagnosis and planning surgical resec
tion of this lesion is discussed.