[Infectious pleurisy as first sign of multiple myeloma in a young 28 years old].

Multiple myeloma is a malignant proliferation of plasma cells, mainly affecting the bone marrow. It rarely occurs in young patients. The medical observation study reveals multiple myeloma discovered through a purulent pleurisy in a 28-year-old subject. This patient was admitted to the pneumology service of the Mohamed V military hospital in Rabat for a fever and dyspnea evolving into a context of poor general condition. Clinical examination found a right pleural fluid effusion syndrome. The pleural puncture reveals a germ-free exudative purulent fluid without plasma cells. The myeloma diagnosis was suspected due to the combination of an aplastic normochromic normocytic anemia at 4.5g/dL of hemoglobin, an accelerated erythrocyte sedimentation rate, hypercalcemia, renal failure and osteolytic lesions located mainly in the skull and pelvis area, oriented by electrophoresis and serum protein immunosubstraction revealing a narrow peak in monoclonal beta-2 globulin at 70.56g/L with a lambda monoclonal gammopathy with immunoglobulin G, and confirmed by the myelogram showing a 74% rate of bone marrow plasma cells. The occurrence of myeloma at a young age is rare and the purulent pleurisy without plasma cells is a rare form of presentation and represents a poor prognosis.