Angiomyomatous hamartoma in an inguinal lymph node with proliferating pericytes/smooth muscle cells, plexiform vessel tangles, and ectopic calcification

Angiomyomatous hamartoma (AMH) is a rare benign lesion, which occurs almost exclusively in the inguinal lymph nodes. We herein report a case of a female elder who presented with a long-standing inguinal mass. Microscopically, the mass showed a zonal distribution, characterized by thick-walled muscular vessels, fibrosis, and calcification in the hilum and proliferating spindle cells around thin-walled vessels and plexiform vessel tangles at the periphery. The spindle cells show positive immunoreactivity of smooth muscle actin and CD34 with a heterogeneous expression of desmin and CD44. Although the pathogenesis of AMH remains uncertain, the histological features and immunohistochemical findings of this case imply a disordered or exuberant angiogenic process.