Primary Kaposi sarcoma of the subcutaneous tissue

Non-cutaneous AIDS-associated Kaposi's sarcoma presenting as recurrent rectal abscesses

Kaposi's sarcoma is a fatal disease that typically presents with cutaneous manifestations in immunocompromised individuals. There are a small number of documented cases where patients diagnosed with this disease present without cutaneous lesions. We present a 35-year-old man with recurrent rectal abscesses and fistula-in-ano, which required multiple drainage procedures. Further investigation revealed a diagnosis of HIV-AIDS, and biopsy of a rectal mass confirmed the diagnosis of visceral Kaposi's sarcoma, despite the absence of cutaneous involvement. Workup revealed hepatic metastasis and a second pulmonary primary malignancy. The patient denied chemotherapy or further intervention and was subsequently lost to follow-up. Prompt diagnosis of Kaposi's sarcoma and initiation of treatment is vital to decrease disease progression. A high index of suspicion should be present in immunocompromised patients, and clinicians must recognise atypical presentations in order to improve long-term survival.

Immunohistochemical detection of the latent nuclear antigen-1 of the human herpesvirus type 8 to differentiate cutaneous epidemic Kaposi sarcoma and its histological simulators

Kaposi's sarcoma is the most common neoplasia diagnosed in AIDS patients and the expression of the human herpesvirus-8 (HHV-8) latent nuclear antigen-1 has been useful for its histological diagnosis. The aim of this study is to confirm that immunohistochemistry is a valuable tool for differentiating KS from its simulators in skin biopsies of HIV patients. Immunohistochemical and histological analyses were performed in 49 Kaposi's sarcoma skin biopsies and 60 of its histological simulators. Positivity was present in the 49 Kaposi's sarcoma skin biopsies and no staining was observed in the 60 simulators analyzed, resulting in sensibility and specificity of 100%. HHV-8 immunohistochemical detection is an effective tool for diagnosing Kaposi's sarcoma, especially in early lesions in which neoplastic features are not evident. It also contributes to its histological differential diagnosis.

Sarcoma de Kaposi em membros inferiores: relato de caso

O sarcoma de Kaposi é uma neoplasia angioproliferativa maligna que na maioria das vezes se restringe à pele e ao tecido subcutâneo; porém, pode aparecer de forma mais agressiva, atingindo a cavidade oral, o trato gastrointestinal e os pulmões (sarcoma de Kaposi visceral). É classificado com quatro variantes clínco-epidemiológicas: clássica, endêmica, iatrogênica e epidêmica, todas associadas ao herpes vírus humano tipo 8. O objetivo desta publicação foi relatar um caso raro de sarcoma de Kaposi em paciente idosa imunossuprimida, não relacionado à síndrome da imunodeficiência adquirida, que evoluiu de forma desfavorável em um período de cinco meses a partir do aparecimento de lesões bolhosas hemáticas e necróticas que, posteriormente, progrediram com intensa exsudação local, desidratação, insuficiência renal e piora do estado geral, evoluindo então a óbito, tendo como causa mortis a falência de múltiplos órgãos.

Pulmonary involvement in Kaposi sarcoma: correlation between imaging and pathology

Kaposi sarcoma is a low-grade mesenchymal tumor involving blood and lymphatic vessels. There are four variants of this disease, each presenting a different clinical manifestation: classic or sporadic, African or endemic, organ transplant-related or iatrogenic, and AIDS-related or epidemic. Kaposi sarcoma is the most common tumor among patients with HIV infection, occurring predominantly in homosexual or bisexual men. The pulmonary involvement in Kaposi sarcoma occurs commonly in critically immunosupressed patients who commonly have had preceding mucocutaneous or digestive involvement.

The etiology of Kaposi sarcoma is not precisely established; genetic, hormonal, and immune factors, as well as infectious agents, have all been implicated. There is evidence from epidemiologic, serologic, and molecular studies that Kaposi sarcoma is associated with human herpes virus type 8 infection. The disease starts as a reactive polyclonal angioproliferative response towards this virus, in which polyclonal cells change to form oligoclonal cell populations that expand and undergo malignant transformation.

The diagnosis of pulmonary involvement in Kaposi sarcoma usually can be made by a combination of clinical, radiographic, and laboratory findings, together with the results of bronchoscopy and transbronchial biopsy. Chest high-resolution computed tomography scans commonly reveal peribronchovascular and interlobular septal thickening, bilateral and symmetric ill-defined nodules in a peribronchovascular distribution, fissural nodularity, mediastinal adenopathies, and pleural effusions. Correlation between the high-resolution computed tomography findings and the pathology revealed by histopathological analysis demonstrate that the areas of central peribronchovascular infiltration represent tumor growth involving the bronchovascular bundles, with nodules corresponding to proliferations of neoplastic cells into the pulmonary parenchyma. The interlobular septal thickening may represent edema or tumor infiltration, and areas of ground-glass attenuation correspond to edema and the filling of air spaces with blood. These findings are a result of the propensity of Kaposi sarcoma to grow in the peribronchial and perivascular axial interstitial spaces, often as continuous sheets of tumor tissue.

In conclusion, radiological findings can play a major role in the diagnosis of pulmonary Kaposi sarcoma since characteristic patterns may be observed. The presence of these patterns in patients with AIDS is highly suggestive of Kaposi sarcoma.