The article presents the case of a 66-year-old non-smoking female patient with HIV-negative status. In 2015, she was diagnosed with chronic lymphocytic leukaemia (CLL) at its early stages, with specific complete blood count changes, peripheral lymphadenopathy and hepatomegaly. No specific treatment was recommended at that time. In July 2018, the diagnosis of non-Hodgkin lymphoma (NHL) IV B stage, with the involvement of all groups of peripheral lymph nodes, was confirmed histologically. No episodes of neutropaenia were recorded. Chemotherapy was initiated. Then, 3 months later, radiological examination revealed a bilateral pulmonary nodular dissemination in the upper lobes, and tuberculous aetiology was confirmed using sputum microscopy and cultural methods (a pansensitive strain). At the end of 8 months of antituberculosis treatment, chest X-ray revealed that apical lung consolidation had diminished, while sputum conversed after 4 months of treatment. After 3 months, the patient presented to the pneumology clinic with haemoptysis. CT revealed bilateral pulmonary consolidation, with cavitation in the left upper lobe and nodules in the surrounding region. Relapse of tuberculosis was excluded microbiologically [this was done using microscopy, cultures and molecular genetic examinations of the sputum and bronchoalveolar lavage (BAL) fluid]. A resistant strain of Staphylococcus aureus (MRSA) was identified, with susceptibility to amikacin and tobramycin. Treatment with amikacin had a positive clinical and imaging effect.