Clinicopathologic Characterization of Kaposi Sarcoma on the Foot and Ankle: Analysis of 11 Patients Seen in Our Clinics.

Background: Kaposi sarcoma (KS) has multiple clinical variants, and most frequently presents on the lower extremities. Anti-human immunodeficiency virus (HIV) therapy has significantly reduced the incidence of KS. However, KS is still prevalent in both HIV-infected and HIV-uninfected patients. This case series analysis aims to reveal the clinical presentations, differential diagnosis, and treatment options of KS on the foot and ankle.

Methods: Eleven cases of KS involving the foot and ankle were retrieved from our patient database, and their clinicopathologic features were analyzed.

Results: All patients were men, aged 29 to 85 years. Two types of KS were found: classic and acquired immunodeficiency syndrome-associated epidemic. The average ages of classic and epidemic KS were 65.7 and 41.8 years, respectively. Clinically, three patients manifested multiple erythematous or deep violaceous, or blue-violaceous macules on either the dorsal or plantar surfaces of both feet. Eight patients showed exophytic, pyogenic granuloma-like nodules on the plantar surface, heels, and toes. Histologically, all KSs had uniform intervening fascicles of elongated spindle cells with slit-like vascular spaces filled with red blood cells and immunoreactivity with human herpesvirus-8. The patients were treated according to HIV infection status. Human immunodeficiency virus-infected patients were treated with anti-HIV therapy after primary surgical excision or biopsy. Human immunodeficiency virus-negative patients were treated with either surgical excision, Mohs surgery, or a combination of surgical excision and local radiotherapy according to individual patient clinical presentation.

Conclusions: Kaposi sarcoma is still prevalent in both HIV-infected and HIV-uninfected patients with a variety of clinical presentations. Biopsy, with histologic evaluation, in combination with immunohistochemistry is essential for the differential diagnosis. The patient should be treated according their clinical manifestation, staging, comorbidity, and immune function.