Kaposi’s sarcoma (Kaposi’s angiosarcoma, angioendothelioma of the skin) is multiple malignant lesions of the dermis developing from the endothelium of lymphatic and blood vessels passing through it. Often the disease is accompanied by damage to the oral mucosa and lymph nodes. Disease manifests itself with multiple bluish-reddish spots on the skin, transforming into tumor nodes up to 5 cm in diameter. Diagnosis includes histology of a biopsy sample from the lesion, an immunity study and a blood test for HIV. Treatment is carried out by systemic and topical application of chemotherapy drugs and interferons, radiation exposure to tumor nodes, cryotherapy.
Kaposi’s sarcoma got its name after a Hungarian dermatologist who first described the disease in 1872. The prevalence is not so great, but among HIV patients it reaches 40-60%. In these patients, Kaposi’s sarcoma is the most common malignant tumor. According to clinical studies conducted in dermatology, Disease is diagnosed in men about 8 times more often than in women.
The risk groups in which the development of Kaposi’s sarcoma is most likely include: HIV-infected men, men of Mediterranean origin in old age, Central African peoples, recipients of transplanted organs or patients receiving long-term immunosuppressive therapy.
Medicine does not yet know the exact causes of Kaposi’s sarcoma and its pathogenesis. The disease often occurs against the background of other malignant processes: fungal mycosis, Hodgkin’s disease, lymphosarcoma, myeloma. Recent studies have confirmed the connection of the disease with the presence in the body of specific antibodies formed when infected with the herpes virus type 8. Infection with the virus can occur sexually, through blood or saliva.
To date, scientists have been able to isolate cytokines that have a stimulating effect on the cellular structures of Kaposi’s sarcoma. These include: 3FGF — fibroblast growth factor, IL-6 — interleukin 6, TGFp — transforming growth factor. In the occurrence of a tumor in AIDS patients, oncostatin is of great importance.
Kaposi’s sarcoma is not an ordinary malignant tumor. Weak mitotic activity, the dependence of the process on the patient’s immune status, multicentric development, the possibility of reverse development of tumor foci, the absence of cellular atypia and histological detection of signs of inflammation confirm the assumption that at the beginning of its occurrence Kaposi’s sarcoma is rather a reactive process than a true sarcoma.
Most often, the disease begins with the appearance of purple-blue spots on the skin, which infiltrate with the formation of rounded discs or nodes. In some cases, disease begins with the appearance of papules on the skin, which is similar to rashes of lichen planus. The nodes gradually grow, reaching the size of a forest or walnut. They have a tightly elastic consistency and a flaky surface, often riddled with vascular asterisks. Nodes cause pain to the patient, which increases with pressure on them. Over time, Kaposi’s sarcoma may cause spontaneous resorption of nodes with the formation of scars in the form of depressed hyperpigmentation.
There are 4 clinical variants: classic, epidemic, endemic and immune-suppressive.
Classical Kaposi’s sarcoma is common in the USA and Central European countries. Its typical localization is the skin of the lateral surface of the shins, feet and hands. It is characterized by a clear outline and symmetry of tumor foci, the absence of subjective symptoms (only in some cases patients notice burning or itching). This form of sarcoma rarely occurs with mucosal lesions. During the classic Kaposi’s sarcoma, there are 3 clinical stages: spotted, papular and tumor.
The spotted stage is the very beginning of the disease. It is represented by red-bluish or red-brown spots of uneven shape, the size of which does not exceed 0.5 cm. The spots have a smooth surface.
The papular stage of Kaposi’s sarcoma has the form of multiple elements protruding above the skin level in the form of spheres or hemispheres. They are dense, elastic, the diameter ranges from 0.2 to 1 cm. Merging with each other, the elements can form hemispherical or flattened plaques with a rough or smooth surface. But more often, individual elements of Kaposi’s sarcoma at this stage remain isolated.
The tumor stage is characterized by the formation of tumor nodes with a diameter of 1 to 5 cm. Nodes, as well as elements of the spotted stage, have a bluish-red or reddish-brown hue. They merge with each other and ulcerate.
Kaposi’s epidemic sarcoma is associated with AIDS and is one of the characteristic symptoms of this disease. Typical is the young age of the patients (up to 37 years old), the brightness of the rash elements and the unusual location of tumors: mucous membranes, the tip of the nose, upper extremities and hard palate. With this form, the lymph nodes and internal organs are rapidly involved in the process.
Kaposi’s endemic sarcoma is found, as a rule, in Central Africa. The disease develops in childhood, more often in the first year of life. It is characterized by damage to internal organs and lymph nodes, skin changes are minimal and rare.
Immune-suppressive Kaposi’s sarcoma proceeds chronically and most benign, as a rule, without involving internal organs. Occurs against the background of ongoing immunosuppressive treatment in patients who have undergone organ transplantation. With the cancellation of immunity-suppressing drugs, the symptoms of the disease often regress.
The course of Kaposi’s sarcoma can be acute, subacute and chronic. With the acute development of the disease, a rapid generalization of the malignant process occurs with the development of intoxication and cachexia. Patients die in the period from 2 months to 2 years from the onset of the disease. The subacute form without treatment can last 2-3 years. The slow development of the tumor process in the chronic form of Kaposi’s sarcoma leads to its longer course (8-10 years or more).
Complications include deformity and restriction of movements in the affected limbs, bleeding from decaying tumors, lymphostasis with the development of lymphedema with compression of lymphatic vessels by the tumor, etc. Ulceration of tumor nodes is dangerous with the possibility of infection, which, against the background of immunodeficiency, leads to the rapid development of sepsis and can cause death.
Diagnosis of Kaposi’s sarcoma is based on its typical clinical manifestations and biopsy data of formations. Histological examination reveals multiple newly formed vessels in the dermis and proliferation of fusiform cells — young fibroblasts. The presence of hemosiderin and extravasates (hemorrhagic exudates) makes it possible to distinguish Kaposi’s sarcoma from fibrosarcoma.
Patients undergo immunological blood tests and an HIV test. To detect lesions of internal organs in Kaposi’s sarcoma, ultrasound of the abdominal cavity and heart, gastroscopy, lung x-ray, skeletal scintigraphy, kidney CT, adrenal MRI, etc
. are used. Differential diagnosis of Kaposi’s sarcoma with lichen planus, sarcoidosis, hemosiderosis, fungal mycosis, highly differentiated angiosarcoma, microvenular hemangioma, etc. is necessary.
An important point in the treatment of Kaposi’s sarcoma is the therapy of the underlying disease to increase the immune status of the body. Systemic treatment of Kaposi’s sarcoma is usually prescribed to patients with a favorable immunological background with an asymptomatic course of the disease. It consists in intensive polychemotherapy. The risk of using such therapy in patients with immunodeficiency is associated with the toxic effects of drugs on the bone marrow, especially in combination with medications for the treatment of HIV infection. At stages 1 and 2 of Kaposi’s sarcoma, one-component chemotherapy with prospidium chloride is considered the most optimal, which is characterized by the absence of an inhibitory effect on the immune system and hematopoiesis. Interferons: α-2a, α-2b and β are successfully used in the treatment of the classical and epidemic form of Kaposi’s sarcoma. They prevent the proliferation of fibroblasts and are able to initiate apoptosis of tumor cells.
Local treatment of Kaposi’s sarcoma includes cryotherapy, injections of chemotherapeutic drugs and interferon into the tumor, applications of dinitrochlorobenzene and ointments of prospidium chloride, etc. methods. In the presence of painful and large lesions, as well as for the best cosmetic effect, local irradiation is carried out.
The prognosis of the disease in Kaposi’s sarcoma depends on the nature of its course and is closely related to the state of the patient’s immune system. With higher levels of immunity, the manifestations of the disease can be reversible, systemic treatment gives a good effect and allows for remission in 50-70% of patients. Thus, in patients with Kaposi’s sarcoma with a CD4 lymphocyte index greater than 400 µl-1, the frequency of remissions against the background of ongoing immune therapy exceeds 45%, and with CD4 less than 200 µl-1, only 7% of patients manage to achieve remission.