A case of multicentric reticulohistiocytosis responsive to azathioprine in a patient with no underlying malignancy.

Multicentric reticulohistiocytosis (MRH), a rare histiocytic systemic condition characterized by mutilating arthritis and multiple cutaneous nodules, has been associated with malignancy including that of the breast, thyroid and colon. An unsubstantiated link with infectious agents such as mycobacterium tuberculosis has been described. Many treatments have been used with varying success. We describe the case of a 60-year-old man with MRH and no underlying malignancy who initially responded well to azathioprine and whose disease recurred upon cessation. A second course of azathioprine administered in conjunction with antituberculous treatment resulted in disease control. Broader associations and features of this rare disease are discussed.