Kaposi’s sarcoma

Definition

Kaposi’s sarcoma consists of multiple malignant lesions of the dermis, developing from the endothelium of the lymph and blood vessels passing through it. Often, the disease is accompanied by lesions of the oral mucosa and lymph nodes. Kaposi’s sarcoma manifests as multiple bluish-reddish spots on the skin, transforming into tumor nodes up to 5 cm in diameter. Diagnosis of Kaposi’s sarcoma includes histology of a biopsy specimen from the lesion, immunity testing, and blood tests for HIV. Treatment is performed by systemic and local application of chemotherapy drugs and interferons, radiation treatment of tumor nodes, and cryotherapy.

General information

The prevalence of Kaposi’s sarcoma is not as high, but among HIV patients, it reaches 40-60%. In these patients, Kaposi’s sarcoma is the most common malignancy. According to clinical studies in dermatology, Kaposi’s sarcoma is diagnosed about eight times more often in men than in women.

Risk groups most likely to develop Kaposi’s sarcoma include HIV-infected men, older men of Mediterranean descent, Central Africans, organ transplant recipients, or patients receiving long-term immunosuppressive therapy.

Causes of Kaposi’s sarcoma

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: mycosis fungoides, Hodgkin’s disease, lymphosarcoma, and myeloma. Studies in recent years confirm the relationship of the disease with the presence in the body of specific antibodies formed when infected with herpes virus type 8. Infection with the virus can occur sexually, through blood or saliva.

To date, scientists have identified cytokines that have a stimulating effect on the cell structures of Kaposi’s sarcoma. These include 3FGF – fibroblast growth factor, IL-6 – interleukin 6, and TGFp – transforming growth factor. Oncostatin is considered to be of great importance in tumor development in AIDS patients.

Kaposi’s sarcoma is not an ordinary malignant tumor. Weak mitotic activity, dependence of the process on the patient’s immune status, multicentric development, possibility of reverse development of tumor foci, absence of cellular atypia, and histological detection of signs of inflammation support the assumption that at the beginning of its appearance, Kaposi’s sarcoma is a reactive process rather than a true sarcoma.

Symptoms of Kaposi’s sarcoma.

The disease most often begins with the appearance of purple-blue patches on the skin that infiltrate to form rounded discs or nodules. In some cases, Kaposi’s sarcoma begins with the appearance of papules on the skin, which is similar to rashes of red squamous fever. The nodules gradually grow to the size of a hazelnut or walnut. They have a dense-elastic consistency and a flaky surface, often pierced by vascular asterisks. The nodes cause the patient pain, which increases when pressure is applied to them. Over time, Kaposi’s sarcoma may spontaneously resorb nodes with the formation of scars in the form of depressed hyperpigmentation.

There are four clinical variants of Kaposi’s sarcoma: classical, epidemic, endemic, and immunosuppressive.

Classic Kaposi’s sarcoma is common in Central Europe. Its typical localization is the skin of the lateral surface of the lower legs, feet, and hands. It is characterized by clear delineation and symmetry of tumor foci and the absence of subjective symptoms (only in some cases do patients note burning or itching). This form of sarcoma very rarely occurs with mucosal involvement. In the course of classical Kaposi’s sarcoma, there are three clinical stages: spotty, papular, and tumorigenic.

The spotty stage is the very beginning of the disease. It is represented by red-blue or red-brown spots of irregular 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 multiple elements protruding above the skin level in the form of spheres or hemispheres. They are dense, elastic, and vary in diameter from 0.2 to 1 cm. Merging among themselves, the elements can form hemispherical or flattened plaques with a rough or smooth surface. However, more often, the individual elements of Kaposi’s sarcoma at this stage remain isolated.

The tumor stage is characterized by the formation of tumor nodules with a 1 to 5 cm diameter. The nodes, like the elements of the spotted stage, are bluish-red or reddish-brown. They merge and ulcerate.

Epidemic Kaposi’s sarcoma is associated with AIDS and is one of the characteristic symptoms of the disease. Typical are the young age of the patients (up to 37 years), the brightness of the rashes, and the unusual location of the tumors: mucous membranes, nasal tip, upper extremities, and hard palate. This form of Kaposi’s sarcoma rapidly involves lymph nodes and internal organs.

Endemic Kaposi’s sarcoma is usually found in Central Africa. The disease develops in childhood, often in the first year of life. It is characterized by the involvement of internal organs and lymph nodes; skin changes are minimal and rare.

Immunosuppressive Kaposi’s sarcoma is chronic and most benign, usually without involvement of internal organs. It occurs against the background of immunosuppressive treatment in patients who have undergone organ transplantation. When immunosuppressive drugs are discontinued, the symptoms of the disease often regress.

The course of Kaposi’s sarcoma can be acute, subacute, and chronic. In the acute development of the disease, there is a rapid generalization of the malignant process with the development of intoxication and cachexia. Patients die in the period from 2 months to 2 years from the onset of the disease. Subacute form without treatment can last 2-3 years. Slow development of the tumor process in the chronic form of Kaposi’s sarcoma leads to its longer course (8-10 or more years).

Diagnosis of Kaposi’s sarcoma

Diagnosing Kaposi’s sarcoma is based on its typical clinical manifestations and the masses’ biopsy data. Histological examination reveals multiple newly formed vessels in the dermis and the proliferation of spindle-shaped cells – young fibroblasts. Hemosiderin and hemorrhagic exudates allow us to distinguish Kaposi’s sarcoma from fibrosarcoma.

Patients undergo immunologic blood tests and HIV testing. To detect lesions of internal organs in Kaposi’s sarcoma, abdominal and cardiac ultrasound, gastroscopy, lung X-ray, skeletal scintigraphy, renal CT, adrenal MRI, etc. are used.

A differential diagnosis of Kaposi’s sarcoma with red flat fever, sarcoidosis, hemosiderosis, fungal mycosis, highly differentiated angiosarcoma, microvesicular hemangioma, etc., is necessary.

Kaposi’s sarcoma treatment

An essential point in treating Kaposi’s sarcoma is the therapy of the underlying disease to increase the body’s immune status. Systemic treatment of Kaposi’s sarcoma is usually prescribed for patients with a favorable immunological background and asymptomatic disease course. It consists of intensive polychemotherapy. The risk of using such therapy in immunodeficient patients is associated with the toxic effects of the drugs on the bone marrow, especially in combination with HIV medications. In stages 1 and 2 of Kaposi’s sarcoma, single-component chemotherapy with propidium chloride, characterized by the absence of a suppressive effect on the immune system and hematopoiesis, is considered the most optimal. Interferons α-2a, α-2b, and β successfully treat classical and epidemic forms of Kaposi’s sarcoma. They inhibit fibroblast proliferation and can 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 propidium chloride ointment, and other methods. Local irradiation is performed for better cosmetic effects in the presence of painful and large lesions.

All these treatment options are available in more than 710 hospitals worldwide (https://doctor.global/results/diseases/kaposis-sarcoma). For example, Chemotherapy for soft tissue sarcoma can be performed in following countries:

Israel in 15 clinics

China in 7 clinics

Germany in 31 clinics

Turkey in 26 clinics

United States in 14 clinics

Kaposi’s sarcoma prognosis

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. At higher immunity indices, the disease manifestations may be reversible; systemic treatment has a good effect and allows remission in 50-70% of patients. Thus, in patients with Kaposi sarcoma with CD4 lymphocyte count more than 400 μl-1, the remission rate on the background of the conducted immune therapy exceeds 45%, and with CD4 less than 200 μl-1 only 7% of patients manage to achieve remission.