Background/introduction Mycobacterial spindle cell pseudotumour is a rare, benign lesion caused by local proliferation of histiocytes in response to mycobacterial infection. It most commonly occurs with mycobacterium avium intracellulare. Most cases affect lymph nodes, skin and brain. We present a case occurring in the lung of a patient with HIV.
Methods A 38 year old Caucasian gentleman was admitted with 1 year history of weight loss, cough and diarrhoea. As a result of declining health and recent HIV diagnosis, he had returned to UK after living 8 years in Thailand. He had commenced anti-TB drugs 6 weeks previously; however no details were available regarding previous investigations. He was profoundly immunosuppressed, with CD4 count < 10 copies/mm3. CT chest showed widespread cavitating lesions throughout both lung fields. Cultures from sputum and bronchial washings grew mycobacterium avium intracellulare and clarithromycin was added. Antiretroviral treatment was started 2 weeks later. Biopsies from bone marrow and bowel showed no evidence of granuloma or malignancy. He suffered frequent episodes of hypercalcaemia. As a result of this, and lack of radiological response to mycobacterial treatment and ARV, CT guided lung biopsy was carried out. This showed mycobacterial spindle cell pseudotumour. Clinically he continued to improve, with immune recovery. Anti-mycobacterial treatment was to continue for 12 months.
Discussion/conclusion Mycobacterial spindle cell pseudotumour is a rare complication of mycobacterial infection. The majority of patients are immunocompromised, including those with advanced HIV. It may share some histological features with Kaposi Sarcoma, therefore correct identification is essential. Treatment depends on the mycobacterial species identified.