A case of multicentric reticulohistiocytosis with multiple lytic skull lesions.

Multicentric reticulohistiocytosis (MR) is a rare multisystemic disorder of unknown aetiology characterized by cutaneous and joint manifestations. It is associated with malignancy in up to 31% of cases. Common radiological findings are peri-articular erosions and osteolytic punched-out areas. We present a case of MR with cutaneous nodules, joint pains, and multiple lytic skull lesions--a combination that has not been described before. Osteolytic activity of proinflammatory cytokines (tumour necrosis factor-alpha and interleukin-1) may explain the peri-articular erosions often seen in MR, and the multiple lytic skull lesions seen in our patient.