Metastatic Kaposi Sarcoma Masquerading as Tuberculosis: A Case Report

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Respected Sir, Kaposi sarcoma is a rare angioproliferative spindle cell tumour that can affect the skin, mucosa or viscera. The prevalence of human herpes virus 8, which is closely associated with the pathogenesis of Kaposi sarcoma, is influenced by a variety of factors, including genetics, the environment and immunosuppression, such as that experienced by acquired immunodeficiency syndrome (AIDS) patients or that caused by immunosuppressive medications.[1] We now present a case of lung-metastasised Kaposi sarcoma. The pulmonary involvement was initially treated with antitubercular drugs for tuberculosis, but it was later discovered that the cause of the involvement was Kaposi sarcoma. A 74 years old male, living in western Maharashtra, India presented with multiple violaceous raised lesions over both legs, the right hand, and the left palm over the previous year. Some of the lesions had a tendency to ulcerate in response to trauma, which caused the lesions to bleed profusely. He had no prior history of oral or genital lesions, lesions with pus, high-risk sexual behaviour or weight loss. The patient received antitubercular medications from a local hospital for 6 months for a cough that had been present for the previous 2 years. A general physical examination revealed pallor. The rest of the general and systemic examinations were normal. A dermatological examination revealed multiple shiny, non-tender violaceous papules and nodules, some of which ulcerated with crusts over the nodule, on both his legs below the knee, the right hand and the left palm [Figure 1]. Patient had normocytic normochromic anaemia and haemoglobin of 9.4 gm%. All biochemical analyses were normal. Serology tests for hepatitis B surface antigen, hepatitis C antibody and human immunodeficiency virus (HIV) were all negative. Contrast-enhanced magnetic resonance imaging (CEMRI) of both legs revealed a few enhancing foci of subcutaneous oedema and altered intensity of muscles in the right leg. A nodule was removed and sent for histopathological analysis with the differential diagnosis of acroangiodermatitis and the classic Kaposi sarcoma. In light of the patient’s history of raising cats at home, bacillary angiomatosis was also taken into consideration as a differential diagnosis. The patient received antitubercular medications from a nearby hospital for 6 months due to a cough that dated back 2 years. Features of reactivated tuberculosis were seen on computed tomography scans of the chest and abdomen. Sputum tests for acid-fast bacteria and Mycobacterial tuberculosis gene experts came back negative. Bronchoalveolar lavage was performed, after which a sample was sent for an acid-fast bacilli stain and mycobacterial culture, both of which came back negative. Histopathological examination showed nodular architecture, slit-like spaces, back to back vessels and spindle cells with no endothelial proliferation. Immunohistochemistry showed diffuse membrane positivity for CD34, weak positivity for CD31 and a Ki67 proliferation index of 30%–40% [Figure 2]. On a fungus culture, there was no growth. Differential cytology revealed neutrophils free of any cancerous cells. However, CEMRI and positron emission tomography–computed tomography revealed thickening of both lower limbs and numerous fluorodeoxyglucose-avid, cutaneous-based nodular lesions. There were scattered ametabolic nodules in the high-resolution computed tomography of the lungs on each side that might be metastases [Figure 3]. Patient was confirmed as a case of Kaposi sarcoma with cutaneous and pulmonary involvement and was started on injection paclitaxel 130 mg per week. After 12 weeks of chemotherapy, patient showed improvement in the form of decrease in the size of the pre-existing lesions [Figures 4-6] and resolution of pulmonary lesions, which was confirmed using contrast-enhanced computed tomography scan.Figure 1: Clinical image of the patient (a-d) showing multiple shiny violaceous papules and nodules on both legsFigure 2: Histopathological examination in 20× (a) and 40× (b) showing nodular architecture, slit-like spaces, back to back vessels (red circle) and spindle cells (black arrow) with no endothelial proliferation. Immunohistochemistry showing diffuse membrane positivity for CD34 (c), weak positivity for CD31 (d) and a Ki67 proliferation index of 30%–40% (e)Figure 3: CEMRI of both legs (a) showing few enhancing foci of altered intensity of muscles of the right leg and subcutaneous oedema. PET–CT (b) showing thickening of both lower limbs with multiple FDG-avid, cutaneous-based nodular lesions involving both lower limbs. HRCT of the chest (c and d) showing ametabolic bilateral scattered lung nodules suspicious for metastasis. CEMRI = contrast-enhanced magnetic resonance imaging, FDG = fluorodeoxyglucose, HRCT = high-resolution computed tomography, PET–CT = positron emission tomography–computed tomographyFigure 4: Clinical image of the patient (a-c) after 12 weeks of chemotherapy showing improvement in the form of decrease in size of the pre-existing lesions and resolution of pulmonary lesionsFigure 5: Pre- (a) and post- (b) clinical images after 12 weeks of chemotherapy show a marked reduction in the size of lesions on both legsFigure 6: Pre- (a) and post- (b) clinical images after 12 weeks of chemotherapy show a marked reduction in the size of lesions on both legsMales of Mediterranean, Eastern European and Jewish ancestry between the ages of 40 and 70 are most commonly affected by the classical form. Although it frequently affects the skin on the lower extremities, it can also harm mucosal and visceral organs like the liver, lungs, kidney, spleen, lymph nodes and gastrointestinal tract. Early Kaposi sarcoma lesions that start as macules usually develop into plaques, which then develop into larger nodules that can develop ulcers, exophytic growths, ulcerated lesions like in our case or invade the surrounding tissues.[2] The characteristic features of Kaposi sarcoma histopathology include abnormal vessels with thin endothelial cell lining that slit the dermis and surround larger ectatic vessels and skin adnexa, producing promontory signs and the presence of inflammatory infiltrates. Plaque stage KS, which mostly affects the dermis and sporadically the subcutis in the skin, is characterised by aberrant proliferation of spindle cells and vessels. Nodules with slit-like spaces have a sieve-like appearance due to spindle cell transection. Kaposi sarcoma lesional cells are positively stained by endothelial markers CD31 and CD34. In addition, it demonstrates several lymphatic-specific markers, including D2-40, LYVE-1, VEGFR-3 and Prox-1.[3] Kaposi sarcoma is known to affect the lungs, pleura or tracheobronchial tree and result in hemoptysis, dyspnoea, a dry cough, fever and other potentially fatal symptoms. Computed tomography scans, which can be used to investigate it, show the presence of a mass, nodules, thickening of the bronchovascular tree and pleural effusions. Spindle cell hemangioma, pseudo-Kaposi sarcoma, bacillary angiomatosis and kaposiform hemangioendothelioma are among the conditions in the differential diagnosis for nodular KS. Kaposi sarcoma is treated differently depending on the type. Immune reconstitution, HIV suppression, tumour removal through surgery, cryotherapy, radiotherapy, and intralesional and systemic chemotherapy are all beneficial in the treatment of AIDS-KS.[4] The antivirals ganciclovir, cidofovir and foscarnet have been shown to be effective against Kaposi sarcoma associated herpes virus. Some of the chemotherapy drugs used to treat KS include vincristine, bleomycin, etoposide, pegylated doxorubicin or daunorubicin, either alone or in combination with paclitaxel as a second-line therapy option. Paclitaxel is frequently used as second-line therapy because it is clinically effective against KS when doxorubicin is not an option. Some of the more recent therapeutic modalities include sirolimus th

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