Purple-red papules on foot

An 88-year-old Caucasian man of Italian ancestry came into our clinic with multiple, painful purple-red "growths" on his left foot that he'd had for several years. The patient had no systemic complaints (no fever, chills, weight loss, night sweats). He had a history of hypertension, a cardiac valve replacement, and chronic back pain (secondary to a motor vehicle accident). He was taking warfarin and nadolol. The patient had multiple, 0.1- to 0.5-cm purple-red papules and nodules on the dorsal and plantar surfaces of the left foot, with associated moderate lower extremity edema and mottled dyspigmentation. We did a punch biopsy, which showed a nodular neoplasm composed of moderately plump, spindle-shaped cells in short interweaving fascicles and numerous extravasated erythrocytes in the spaces ("vascular slits") between the spindle-shaped cells. What is your diagnosis, and how would you manage this condition?