How should I approach the diagnosis of Kaposi's sarcoma in a patient presenting with skin lesions and a history of HIV?

Approach to Diagnosing Kaposi's Sarcoma in an HIV-Positive Patient with Skin Lesions

In a patient with a history of HIV infection presenting with suspicious skin lesions, the initial clinical assessment should focus on a detailed history and physical examination to characterise the lesions, which typically appear as violaceous, reddish, or brownish macules, plaques, or nodules. Given the strong association between Kaposi's sarcoma (KS) and HIV, especially in immunocompromised individuals, a high index of suspicion is warranted NICE NG12.

Definitive diagnosis requires a skin biopsy of the lesion for histopathological examination, which reveals characteristic spindle cell proliferation, neovascularisation, and extravasated red blood cells. Immunohistochemical staining for human herpesvirus 8 (HHV-8) latent nuclear antigen is essential to confirm the diagnosis, as HHV-8 infection is a necessary factor in KS pathogenesis NICE NG12.

Additional investigations should include assessment for visceral involvement, as KS can affect mucous membranes, lymph nodes, and internal organs such as the lungs and gastrointestinal tract. Imaging and endoscopic evaluations may be indicated based on clinical suspicion Epelbaum et al. 2016. Pulmonary KS, although less common, can complicate the clinical picture and requires prompt recognition Epelbaum et al. 2016.

Given the frequent coexistence of lymphedema with KS lesions, clinical evaluation for limb swelling is important, as it may influence management and prognosis Dauguet et al. 2023. Early referral to oncology or specialist HIV services is recommended for confirmation of diagnosis and initiation of appropriate antiretroviral therapy and oncological treatment NICE NG12.