Multiple myeloma with numerous intranuclear Russell bodies.

Correspondence: A. Martín-Noya, M.D., Servicio de Hematología, Hospital Universitario Virgen del Rocío, Avda. Manuel Siurot s/n1, 41013 Seville, Spain. Phone: international +34-95-4248122 – Fax: international +34-954248124 – E-mail: [email protected] A71-year-old woman was admitted to hospital because of repeated episodes of epistaxis and an eight month history of fatigue and weight loss. On physical examination she appeared pale. Hemoglobin level was 72 g/L, the WBC count 5.63109/L and the platelet count 3003109/L. A peripheral blood smear revealed normochromic anisocytosis and rouleaux formation, and 2% plasma cells. The ESR was 166 mm in the first hour. Serum protein level was 103 g/L with a homogeneous component of 36 g/L on the g-globulin peak. Serum level of IgG was 3099 mg/dL, of IgA 11 mg/dL and of IgM 18 mg/dL. Immunoelectrophoresis showed a monoclonal IgG-k in serum and k light chains in urine. The bone marrow aspirate demonstrated 72% moderately undifferentiated plasma cells, some of them binucleated. There were Russell bodies (RB) in 32% of the plasma cells, their location being cytoplasmic in 5%, intranuclear in 26% and both cytoplasmic and nuclear RB in 1%. Of these plasma cells containing RB, 8% had from 7 intranuclear inclusions (Figures 1 and 2) up to 31 inclusions, 10% had between 4 and 6 and 82% had fewer than 4. The intranuclear RB were negative for myeloperoxidase, Sudan black B, periodic acid-Schiff, acid phosphatase, b-glucuronidase, non-specific esterases (anaphthyl-acetate-esterase), methyl green pyronine and Perls’ stain. The bone marrow biopsy showed a diffuse plasma cell infiltration. Plasma cell RB stained red for Masson’s trichrome. This ultrastructural study proved the inclusions to be RB, characterized by homogeneous material bound by a single membrane (Figure 3) located in the rough endoplasmic reticulum (RER) and mainly within the nucleus. The patient was treated with intermittent courses of melphalan and prednisone, achieving partial remission and remaining alive at 21+ months. RB, composed of protein, are situated in dilated RER cisternae. In rare cases of multiple myeloma, RB are found within the cell nucleus, surrounded by a