Unusual leiomyoma of vulva with fibroma-like pattern and pseudoelastin production

A unique case of a 71-year old woman with an unusual fibroma-like leiomyoma of the vulva in the region of the left Bartholin's gland is reported. Light microscopically the tumor resembled a fibroma, but electron microscopically the cells corresponded to modified smooth muscle cells. The great number of vessels and their intimate relation to the tumor cells is remarkable. In the intercellular space granular and fibrillar pseudoelastic material was found and thus the presence of collagen type III in addition to type I is suggested. In the region of the right Bartholin's gland a mesenchymal proliferation with similar histological features was seen but there was more resemblance to a conventional leiomyoma. The histogenesis remains obscure so that the designation of these lesions should include light microscopic and electron microscopic appearances as well as localization.