Kaposi sarcoma (KS) is an angioproliferative neoplasm related to human herpes virus 8 (HHV8). Five clinical variants have been described, ranging from Classic KS (CKS), African endemic KS, immunosuppressed-related form, KS in HIV-negative men who have sex with men and AIDS-related KS ^{[1][2][3][4][5]}[1,2,3,4,5]. The incidence of classic KS is higher in Mediterranean countries, and the overall Italian incidence rate has been estimated to be 1/100,000 in men and 0.4/100,000 in women. Iatrogenic KS is commonly detected in organ transplant recipients (OTR), with an increased risk estimated to be from 100 to 500 times higher than in the general population. Regarding the clinical aspects, skin manifestations can range from pink to violaceous papules, patches, and ulcerated nodules. CKS usually involves the legs, and lymphedema is the most common cutaneous complication. Oral, genital or conjunctival involvement can be detected at physical examination [6], and in advanced stages, lymph node and visceral (bladder, lung and kidney) involvement are possible. CKS has an indolent clinical behavior, while the remaining forms are more aggressive and easily involve lymph nodes or visceral organs [2]. Besides CKS, which usually affects the sixth decade, patients of any age can be affected, and pediatric cases have been recorded ^[7][8][7,8]. Histology is crucial for KS diagnosis. Skin lesions show similar features and patches with a perivascular infiltrate of scattered plasma cells and lymphocytes. A proliferation of oddly-shaped endothelial cell-lined vascular channels behind the existing blood vessels is a clue for KS diagnosis. Such channels become more prominent in patch lesions along with the presence of CD31+ and CD34+ spindle cells. In nodular lesions, a dermal mass of spindle cells is visible with light microscopy along with extravasated red blood cells.

In immunohistochemistry, staining against HHV-8 results in positive staining in spindle cells. Scheduled treatments depend on the clinical variant, KS extension and immune system status. Dermoscopy of KS can be helpful, and polychromatic color change (Rainbow pattern), collarette sign, white lines, white clouds, and serpentine vessels have been related to KS, especially in the case of nodular lesions [9]. The Italian recommendations [6] suggest treating with local therapy, (mainly intralesional vincristine or silver nitrate cauterization) as lesions can negatively affect patients’ quality of life in case of indolent KS lesions. Aggressive, diffuse and visceral KS should be managed with systemic treatments such as vinblastine alone, vinblastine associated with bleomycin, or paclitaxel [6] (Brambilla IJDV 2021). In immunosuppressed patients, medication changes usually lead to KS regression ^[2][10][11][2,10,11]. In HIV-related forms, pegylated liposome doxorubicin or paclitaxel are commonly used along with ART (Antiretroviral Therapy) ^[6][12][13][6,12,13].