A Case of Patch Stage of Kaposi's Sarcoma and Discussion of the Differential Diagnosis

Very Early Patch Stage of AIDS-related Kaposi Sarcoma: A Case Report

Kaposi sarcoma (KS) is a vascular and lymphatic neoplasm caused by human herpesvirus 8 (HHV-8). AIDS-related KS has variable clinical courses ranging from mild disease presenting as an incidental finding to severe disease presenting as an aggressively progressing neoplasm that can lead to poor prognosis or even death. Typical clinical manifestation of KS is known as multiple cutaneous lesions on the extremities, trunk, and face with mucosal involvement. A 46-year-old male with AIDS complained of an erythematous patch on the right forearm which appeared 5 months ago. For a year, he was treated with antiretroviral drugs for AIDS. Physical examination revealed a 2.5-cm solitary erythematous patch only on the right forearm. Laboratory data revealed human immunodeficiency virus (HIV)-1 RNA of less than 40 copies/ml and a CD4 cell count of 264 cells/mm3. Histological examination revealed numerous slit-like spaces and vascular proliferation with primitive blood vessels dissecting between the collagen bundles and the dermis. Immunohistochemical staining showed positive HHV-8 nuclear staining of spindle cells. The histological features and positive HHV-8 immunohistochemical stain were consistent with the diagnosis of early patch stage of AIDS-related KS. KS can readily be misdiagnosed in early patch stage even by experienced clinicians, which leads to requirement of pathologic determination. On close inspection, it can be distinguished from other mimickers by its distinctive histologic features and immunohistochemical staining for HHV-8. Therefore, in cases of HIV-positive patients with clinically or histologically vascular-appearing mucocutaneous lesions, KS should be considered as a possible differential diagnosis.

Kaposi sarcoma misdiagnosed as granuloma annulare: A case of mistaken identity

The microscopic features of patch stage Kaposi sarcoma (KS) and interstitial granuloma annulare (GA) may be difficult to differentiate, because both may exhibit a subtle "busy" dermis due to infiltration of spindled cells between collagen bundles. The clinical distinction is particularly challenging in human immunodeficiency virus (HIV)-affected individuals, as the incidence of GA appears to be greater in the HIV-infected population. KS is the most common neoplasm in this population. Despite the significant decrease in the incidence of KS since the advent of highly active antiretroviral therapy (HAART), KS tends to occur with late onset and indolent progression in patients with preserved immune function and minimal viral load. We present a 47-year-old homosexual HIV-positive man, under virologic and immunologic control on long-term HAART therapy, with a 5-year history of progressive red-brown patches and plaques on the legs, feet, hands, and trunk. Prior skin biopsy specimens were interpreted as interstitial GA. Histopathology on new skin biopsy specimens along with review specimens supported the diagnosis of plaque and patch stages of KS, respectively, supported by immunohistochemical expression of human herpes virus-8 (HHV-8). This case underscores the importance of maintaining a high suspicion for KS in progressive, treatment-recalcitrant skin lesions, particularly in HIV-infected individuals.

Metastatic Angiosarcoma of Lower Extremity

Angiosarcoma (AS) is an uncommon malignant neoplasm characterized by rapidly proliferating, extensively infiltrating anaplastic cells derived from blood vessels. These are aggressive tumors and tend to recur locally, spread widely with high rate of lymph node and systemic metastases. They are more frequent in skin and soft tissue, head and neck being the most common sites. Here we report a case of metastatic AS affecting lower extremity in an elderly patient on a background of chronic lymphedema due to filariasis (Stewart–Treves syndrome).