Background: Kaposi's sarcoma is commonly described in HIV/AIDS patients but usually manifests as overt skin lesions or visceral involvement. Bone involvement, particularly vertebral, is uncommon, especially when there is no adjacent cutaneous lesion but a small number of cases have been reported. Unlike many other diseases associated with HIV, Kaposi's sarcoma can occur despite a normal CD4 count.
Case presentation: A 44 year-old HIV positive Nigerian man presented with a 20 day history of severe, worsening lumbar back pain, nearly three years after an earlier diagnosis of a single cutaneous lesion consistent with Kaposi's sarcoma, for which he received chemo-radiotherapy. Despite varying previous compliance with his anti-retroviral therapy, he was thought to be taking his medications at time of presentation and his CD4 count was 408 cells/mm(3). No other organ involvement was found but a pathological fracture was seen on magnetic resonance imaging affecting L1 vertebra. A CT-guided needle aspiration biopsy was performed and a histological diagnosis subsequently confirmed Kaposi's sarcoma. The patient was treated with further courses of radiotherapy but had little clinical improvement. Indeed, a follow-up MRI four months later showed new involvement of a further four vertebrae, fortunately in the absence of progressive focal neurology.
Conclusion: Vertebral Kaposi's sarcoma is a rare diagnosis but can be accurately diagnosed with CT or MRI imaging in conjunction with a histological diagnosis. An immunosuppressed patient presenting with bone pain should be thoroughly investigated for Kaposi's sarcoma as modern chemotherapeutic agents alongside anti-retroviral therapy may delay or prevent further devastating complications such as spinal cord compression.