What are the precursors to the appearance of Kaposi’s sarcoma in HIV?

Skin lesions are the most common and are a common first manifestation of Kaposi’s sarcoma. Skin lesions in KS appear to be most common on the lower extremities, face (especially the nose), oral mucosa, and genitalia. The lesions tend to be oval and arranged in a linear pattern along the skin tension lines; they may be symmetrically distributed. The lesions are painless and itchy and usually do not cause necrosis of the surface skin or underlying structures. The color of these lesions depends on their degree of vascular enrichment and can appear pink, red, purple, and brown, with an occasional yellow halo around the lesion. Early lesions are easily misdiagnosed as purpura, hematoma, hemangioma, dermatofibroma, or nevus. However, in more cases, KS lesions present as papules several millimeters to centimeters in diameter. In rarer cases, they may also appear plaque-like, especially on the soles and femurs, or exophytic and mycotic with surface skin destruction.