Intravascular Fasciitis in the Temporal Region: A Rare Presentation in a Young Adult

Summary: We present the case of a 21-year-old male with a 1.8 x 0.5 cm nodular growth in the temporal area, which was clinically diagnosed as an epidermoid cyst. The subsequent excision histologically revealed a deep dermal nodule composed of spindle cells with mucinous degeneration and vascular proliferation at the periphery, consistent with intravascular fasciitis (IVF). IVF is a rare variant of nodular fasciitis, consisting of a reactive benign proliferation of fibroblasts and myofibroblasts involving the blood vessels, a feature that can lead to misdiagnosis as intravascular invasion of a sarcoma. IVF was first described in 1981 by Patchefsky and Enzinger, and since then, 57 cases have been reported in the literature. IVF typically presents as a soft, painless, mobile mass and occurs most commonly in the upper extremities, followed by the head, neck, trunk, and lower extremities. It usually involves small and medium-sized vessels, but large vessel involvement has also been reported, including the femoral vein and ascending aorta. Our case aims to raise awareness of this rare variant of nodular fasciitis to prevent misdiagnosis of vascular spindle cell growths and to differentiate them from malignancies in young adults.