This is a benign, reactive vascular proliferation on the lower legs, arising in the setting of chronic venous insufficiency, a different context than HIV or immunosuppression-related KS.
This is a highly aggressive vascular malignancy, often presenting as an ill-defined, "bruise-like" lesion on the scalp or face of the elderly, with more rapid growth and infiltration than typical KS.
Caused by Bartonella infection in immunocompromised patients, these lesions are bright red, friable, papules and nodules that resemble pyogenic granulomas, unlike the more violaceous, non-friable lesions of KS.
A skin metastasis can be a firm, violaceous nodule, but it is distinguished by the identification of a primary internal cancer.
A bruise is a flat patch of extravasated blood that resolves and changes color over time, whereas a KS patch is a persistent, neoplastic lesion that does not fade.
A cherry angioma is a benign, bright red papule, and an infantile hemangioma is a lesion of infancy, both distinct from the purple patches and plaques of KS in adults.
This is a benign, reactive lymphocytic infiltrate that can present as a reddish-purple nodule, but it lacks the slit-like vascular spaces and spindle cells seen on KS biopsy.
