Kaposi’s sarcoma in association with generalized tuberculosis is a rare combination of two opportunistic HIV-associated diseases, and the difficulties of their detection are especially relevant in the context of the COVID-19 pandemic. To demonstrate a clinical case of multisystem involvement by Kaposi’s sarcoma and pulmonary tuberculosis in a patient admitted to an infectious diseases hospital with suspected viral pneumonia caused by a new coronavirus infection COVID-19. The patient complained of general weakness, shortness of breath with minimal physical exertion, heavy sweating, cough with yellow-green sputum, fever up to 37–39°С, lack of appetite and weight loss of 13 kg over the past six months. The analysis of clinical data, laboratory, instrumental and pathoanatomical studies performed in a St. Petersburg’s infectious diseases hospitals was carried out. CT findings of generalized lymphadenopathy combined with lung infiltrates in a patient with a positive PCR test for a new coronavirus infection (COVID-19) led to the overdiagnosis of a lymphoproliferative disease and did not allow for Kaposi’s sarcoma to be detected in vivo due to the absence of typical CT findings of disseminated tuberculosis in the presence of bilateral pneumonia. Radiologists should be aware of the clinical picture and signs of Kaposi’s sarcoma, it must be included in the differential diagnosis if a patient has an atypical clinical presentation and course of the disease, in the presence of skin rashes, even with a positive PCR for COVID-19.