Kaposi’s sarcoma

Kaposi’s sarcoma is also called as angioreticuloendothelioma. It is most common tumour associated with AIDS & occurs in 1/3 rd of AIDS patients.

Etiology

• Higher incidence of Kaposi’s sarcoma is in homosexual men with AIDS as compared to heterosexuals with AIDS
• It has been suggested that there is transmissible agent prevalence in homosexual population, which stimulate certain factor such as angiogenesis protein that may be critical in the pathogenesis of neoplasm.
• The patient with AIDS often shows clustered lesion in the oral cavity which suggests direct inoculation of mucosa with sexually transmitted agent.
• Some theories suggests role of cytomegalovirus in the pathogenesis of Kaposi’s sarcoma, but studies on prevalence of antibodies to cytomegalovirus in patient with classic & epidemic Kaposi’s sarcoma have failed to demonstrate role of cytomegalovirus.

Epidemiology & Form

• Kaposi’s sarcoma appear in various forms like

1. Classic
2. African(cutaneous variant)
3. African(lymphadenopathy variant)
4. Kaposi’s sarcoma associated with AIDS.

1. Classic type is rare neoplasm and occurs in older man.  Usually it appears as blue-black macule on the lower extremities. It is slow growing & rarely involves the lymph nodes & visceral organs.
2. African Kaposi’s sarcoma is considered an endemic disease & affects children, 10 year old or younger patients, more common in men than women. It appears as exophytic  growth located in legs & arms.This form is locally aggressive & lymph nodes involvement is rare.The lymphadenopathic form occurs in children of 10  years age & younger with same frequency in men & women.The visceral & massive nodal involvement is common.
3. Kaposi’s sarcoma is observed in patients with kidney transplantation and in patients who receive the immunosuppressive drugs for variety of diseases. Drugs such as prednisolone ,cyclosporine and cyclophosphamide have been associated with development  of Kaposi’s  sarcoma.It usually affects legs, arms, lymph nodes & visceral organs.
4. Kaposi’s sarcoma with AIDS is common in homosexual but can occur in all risk groups. Male to female ratio is 20:1. Generally affects skin, oral & visceral organs.

Clinical features

• Site-it occurs commonly in head & neck region. Tip of nose is peculiar & frequent location of it.It can involve lymph nodes, soft tissues, extremities, GIT, lung,liver, pancreas, spleen & adrenal gland.
• Age-It can occur at any age but most common in 5^th to 7^th decades except in Africa where it occurs in children.It occurs  mostly in men but also had been observed in women.
• Appearance-it begins as multinucleated neoplastic process that manifests as multiple red or purple macules & in more advanced stage, a nodule occurring on the skin or mucosal surface.
• Size-size of it ranges from a few millimetres  to a centimetres or more in diameter & are usually tender on palpation.It is slow growing but can behave as a very aggressive lesion with rapid visceral involvement.

Oral manifestations

• Site-it had tendency to involve the oral cavity, with hard palate as the most common site.But lesions may occur on any part of the oral mucosa including the gingival, soft palate, buccal mucosa & in the oropharynx.It can involve either alone or in association with skin & disseminated lesions.It may be the first symptom of AIDS.
• Appearance-It can appear as a red, blue or purplish lesion. It may be flat or raised solitary or multiple.Occasionally , yellowish mucosa surrounds the lesion. The lesions may enlarge, ulcerate& become infected. Good oral hygiene is essential to minimize these complications.
• Size-it may vary in size from few mm to a centimetre or more in diameter and are tender & painful.

Histopathological features

• It consists of interweaving band of spindle shaped and or pulp endothelial cells and atypical vascular channels, enmeshed in reticular  or collagen fibres.
• It consists of numerous, small capillary type blood vessels which may or may not contain blood
• Inflammatory cells infiltration is common
• In late stage, lesion consists of well defined nodules or lesions with diffuse involvement of the lamina propria

Management

• Treatment is determined according to the number, size & location of lesion..The choice of therapy depends on the effect of treatment on the adjacent mucosa, pain associated with treatment,interference with eating & speaking & the patients preference .It is important to perform through dental prophylaxis before initialising treatment for lesions involving gingival.Local application of sclerosing agents may reduce size of oral lesions.
• Local treatment is appropriate for large oral lesions that interfere with eating & talking.Oral lesions can be treated surgically or with localised intralesional chemotherapy.
• Surgial removal is suitable for small, well-circumscribed lesions such as gingival or tongue lesions.Surgical removal can be performed  under L.A with a blade or with carbondioxide laser.
• Intralesional  vinblastine(0.1 to 0.2 mg per ml solution) is useful in treating small lesions on palate or gingival.
• Radiation therapy may be indicated for large multiple lesions.
• Intravenously interferon alpha & sclerotherapy with 3 % sodium tetradecyl sulphate.

Prognosis

Poor with mean survival time 6-14 months.