Fine-needle aspiration diagnosis of Kaposi's sarcoma in a developing country

Fine-needle aspiration (FNA) cytology was performed on 15 patients with peripheral lymphadenopathy and/or skin lesions referred to the Department of Pathology of the Hospital Central of Maputo, Maputo, Mozambique. Epitrochlear lymph nodes were the most frequently aspirated site. All aspirates allowed diagnoses of Kaposi's sarcoma (KS). Smears contained loosely cohesive clusters of bland spindle cells, with a radial arrangement and nuclear crush artifacts. These diagnostic clues have not been described in other spindle-cell intranodal lesions that should be considered in differential diagnoses. Taking into consideration the high prevalence of AIDS and limited resources for diagnosis in Africa, FNA cytology appears to be a useful method for the diagnosis of KS in developing countries, reducing the necessity for surgical lymph node excision.     

Kaposi's sarcoma revisited

Kaposi's sarcoma is a puzzling condition of unclear, possibly endothelial origin. It is divided into four distinct types regarding the affected population: classic in elder men of Ashkenazi Jewish and Mediterranean origin; endemic in African infants and young males; iatrogenic in patients under immunosuppressive regimens; epidemic in men having sex with men affected by AIDS. The exact etiopathogenesis of Kaposi's sarcoma continues to elude its researchers. Nonetheless, it has been discovered that human herpesvirus 8 is essential but not sufficient for sarcoma development. Also, iron exposure of populations inhabiting regions with volcanic soils has been suggested to play a pivotal role in the classic and endemic Kaposi's sarcoma etiology. The epidemic Kaposi's sarcoma is strongly associated with HIV's detrimental effect on immune system and HIV's Tat protein proangiogenic properties. Because Kaposi's sarcoma is found also in men having sex with men without AIDS, it has been proposed that certain lifestyle features (e.g. massive semen exposure and inhalant nitrites) may promote transformation of endothelial cells of both lymphatic and vascular origin. Despite numerous studies on Kaposi's sarcoma, it continues to be an incurable disease. The therapeutic approach includes local treatment and systemic administration of cytotoxic, immunomodulator and antiviral drugs. Because of the increasing prevalence of Kaposi's sarcoma, especially in certain parts of Africa, a better understanding of this condition is necessary.     

Histogenesis of Kaposi's sarcoma

The origin of Kaposi's sarcoma from the endothelium and fibroblast-like cells of a vascular wall is proven on the basis of complex pathomorphological, immunomorphological, autoradiographic and electron microscopical investigation of tumour biopsies. Depending upon the predominating cell type of origin, the tumour in its different parts, may form the structures of either different variants of angiomas or fibrosarcomas.     

Kaposi's sarcoma of the testicle

The penis and scrotum are the genitourinary tract organs most frequently involved in Kaposi's sarcoma (KS). However, solid organ involvement is rare. A 32-year-old man with AIDS presented with cutaneous KS, which subsequently metastasized to the right testicle.     

Kaposi's sarcoma and HIV.

Recently published informed debate affords strong indication that in patients with the Acquired Immune Deficiency Syndrome, HIV cannot, directly or indirectly, be the cause of Kaposi's sarcoma. This paper provides reasons for disallowing a current alternative theory that Kaposi's sarcoma is due to an unidentified sexually transmitted infectious agent and proposes instead that Kaposi's sarcoma is the result of prolonged and repeated exposure to nitrites and/or semen. If this alternative hypothesis is strengthened by confirmation of its predictions then the relationship of HIV to Kaposi's sarcoma, one of the principal AIDS-associated diseases, becomes somewhat remote. This may facilitate a shift of emphasis and encourage the development of alternative therapies.     

Rapidly fatal lymphangioma-like Kaposi's sarcoma

A 34-year-old black South African male was treated for lymphangioma-like clinical Kaposi's sarcoma. The disease followed a rapidly fatal course and was characterized by unexplained recurrent pleural effusions and severe refractory anaemia due to the presence of dilated vascular channels in the bone marrow. Definitive diagnosis was only made at autopsy. Lymphangiomatous changes in the skin without spindle cell formation caused diagnostic difficulties.     

Factor VIII in Kaposi's sarcoma

The immunoperoxidase technic was applied to 15 skin lesions of Kaposi's sarcoma to localize factor VIII-related antigen. Factor VIII-related antigen serves as a tissue-specific marker for endothelial cells. Positive staining was observed in all cases. These findings support the endothelial origin of the lesion of Kaposi's sarcoma.     

Kaposi's sarcoma of the bone marrow

We report a case of Kaposi's sarcoma of the bone marrow presenting as a myelophthisic anemia with bone marrow necrosis. The patient did not fit into any of the current clinical patterns described for Kaposi's sarcoma. This case illustrates the need for including Kaposi's sarcoma in the differential diagnosis of myelophthisic anemia.