Vulvar Leiomyosarcoma Masquerading as a Bartholin's Gland Cyst in an Adolescent.

Sarcomas, tumors of mesenchymal origin, comprise a small percentage of all malignant tumors and are often challenging to diagnose. Leiomyosarcoma (LMS) is a rare form of cancer arising from smooth muscle cells. While a soft tissue sarcoma diagnosis is rare in and of itself, LMS diagnosis at an adolescent age is even more unique. Vulvar LMS can easily be misdiagnosed as a benign vaginal lesion, leading to a delay in proper treatment and poorer outcomes. In this case, we present a 14-year-old female who was diagnosed with a grade 2 vulvar LMS that clinically mimicked a Bartholin's gland cyst.