Waldenstrom's macroglobulinemia presenting with lytic bone lesions: a rare presentation
A 65-year-old male patient, who had a 10-year history of hypertension and type II diabetes mellitus, presented with complaints of pain and a tingling sensation in both lower limbs over the previous year and in both upper limbs over the previous 6 months. He also had a history of weight loss and an intermittent low-grade fever during the previous 6 months.\nOn examination, the patient was pale, conscious, alert, and oriented with a pulse of 72 beats per minute and blood pressure at 140/90 mmHg. Nothing unusual was found on examination of the chest and cardiovascular systems. Abdominal examination revealed mild hepatomegaly without splenomegaly. Examination of the nervous system showed normal mental status (patient was conscious and well oriented in time, place, and person). Sensations were diminished below the knees in both lower limbs. Power in all of the muscles was 4/5. Fundoscopy revealed a grade 4 hypertensive retinopathy.\nInvestigations revealed pancytopenia and normocytic normochromic anemia with a hemoglobin of 6.8 g/dL; a total leukocyte count of 1.5×103/mm3; a differential leukocyte count with 23% neutrophils, 71% lymphocytes, 5% monocytes, and 1% eosinophils; a platelet count of 21,000/mm3; and a markedly raised erythrocyte sedimentation rate of 140 mm/hr. Biochemical investigations provided the following results: blood sugar, 92 g/dL; total bilirubin, 0.6 mg/dL; alkaline phosphatase/aspartate transaminase/alanine transaminase, 126/74/55 IU/mL; blood urea, 74 mg/dL; serum creatinine, 1.7 mg/dL; and serum uric acid, 11 mg/dL. The serum protein level was 10.0 g/dL, albumin level was 1.76 g/dL, and the albumin/globulin ratio was 0.2 (reference range, 0.9-2.0). Serum calcium levels ranged from 8.4 to 9.2 mg/dL on different occasions. The venereal disease research laboratory (VDRL), antinuclear antibody, and rheumatoid factor tests were negative, while C-reactive protein was raised. The Coombs test and the test for cold agglutinins were also negative. In addition, the serological markers for hepatitis B and hepatitis C were negative. The skull radiograph revealed multiple lytic lesions.\nThe chest radiograph showed cardiomegaly with prominent bronchovascular markings. Ultrasonography revealed mild hepatomegaly (15.5 cm in size), while the spleen and both kidneys were within normal limits. The wall of the rectum and sigmoid colon demonstrated thickening. Contrast enhanced computed tomography (CECT) revealed atrophy of the brain and multiple lytic lesions in the skull. The rectal wall was also edematous. There was mild hepatomegaly with the presence of minimal ascites. A clinical diagnosis of multiple myeloma was considered due to the presence of lytic bony lesions, increased total protein values, decreased serum albumin, and low albumin to globulin ratio.\nBone marrow aspiration, bone marrow biopsy, and serum protein electrophoresis were simultaneously performed to confirm the diagnosis of multiple myeloma. Bone marrow imprint smears were hypercellular with the presence of numerous bare nuclei, which were predominantly lymphoid cells with a few plasmacytoid cells (). The bone marrow biopsy revealed a hypercellular marrow with diffuse infiltration of a spectrum of lymphoid cells that were predominantly small lymphocytes, plasmacytoid lymphocytes, a few plasma cells, and mast cells (). The erythroid, myeloid, and megakaryocytic series were markedly suppressed. Therefore, a diagnosis of lymphoplasmacytic lymphoma was considered. Immunohistochemical staining revealed 2 populations of cells; the predominant population was strongly positive for CD20 (lymphocytic cells) ( inset) while the other population was positive for CD138 (plasmacytic cells). CD5 and CD23 were negative, which ruled out chronic lymphocytic leukemia/small lymphocytic lymphoma. The serum protein electrophoresis revealed the following: total protein, 10.5 g/dL (range, 6.4-8.1); albumin, 1.76 g/dL (range, 3.50-5.64); gamma globulin, 7.18 g/dL (range, 0.62-1.53); and albumin to globulin ratio, 0.2 (range, 0.9-2.0), with an M spike of 5.98 g/dL. Immunofixation electrophoresis revealed IgM kappa light chains. Thus, a final diagnosis of WM was established.