Brain Pathology Case of the Month - December 2007

Contributed by Barbara Germin 1, Ajay Malhotra2, Vassilios Dimopoulos 3, Raymond Felgar1
1Pathology and Laboratory Medicine, 2Neuroradiology, 3Neurosurgery, University of Rochester Medical Center


A 56-year-old male presented with a 2-3 week history of left-sided weakness and intermittent loss of balance. Past medical history was significant for bone marrow biopsy-proven IgG lambda light chain multiple myeloma (MM), Durie-Salmon stage IIIB with complex hyperdiploid karyotype diagnosed in 02/2004. He had measurable serum (4.0g/dl) and urine (463.7mg/dl) paraprotein, increased calcium at 10.4mg/dl (Normal reference range: 8.6-10.2mg/dl), high creatinine at 4.5mg/dl (Normal reference range: 0.7-1.3mg/dl), high BUN at 78mg/dl (Normal reference range: 8-22mg/dl) and low hematocrit at 30% (Normal reference range: 42-52%). Our patient also had multiple lytic bone lesions, ascites, and splenomegaly at presentation. He was treated with tandem autologous bone marrow transplants in June and September of 2004; was maintained on thalidomide and prednisone. He relapsed in July 2006 with subcutaneous lumps in the left elbow and left flank and a large left sided perinephric mass. The subcutaneous lesions were confirmed on biopsy to be extramedullary myeloma. On motor exam he had mild spasticity in the left upper and lower extremities with a left pronator drift. Strength was 4-5/5 in the left upper and lower extremities. He had diffuse lower extremity deficits in light touch sensation and left-sided dysmetria.


MRI of the brain revealed a large, well-defined lesion in the right high fronto-parietal region measuring approximately 5 x 4.7 x 4.6 cm. The mass was predominantly cystic with peripheral rim enhancement. A nodular enhancing component was seen postero-superiorly with thick enhancing septae. There was no significant perilesional edema, and no mass effect or midline shift. Perfusion images showed foci of increased regional cerebral blood volume (rCBV) in the nodular enhancing focus (Figures 1a, 1b).

He underwent a right parietal craniotomy for subtotal tumor resection. After corticectomy, a cystic tumor was localized and aspirated. The tumor appeared soft and grayish in color and had a gelatinous quality.


The resection specimen was composed of multiple tan/maroon-pink tissue fragments, the largest of which was 1.6 cm. in greatest dimension. The tissue was extensively mucoid in appearance. Microscopically, the tumor was arranged in sheets and trabeculae of cells in a background of proteinaceous material (Figure 2). Many of the neoplastic cells had a characteristic chromatin pattern (Figure 3). On immunohistochemistry, the tumor cells were diffusely, strongly positive for CD138 (Figure 4), with clonal lambda immunoglobulin light chain expression by in situ hybridization. The tumor cells were negative for GFAP, TTF, CD3, CD20, and CD79a. Flow cytometry demonstrated a monomorphic population of cells marking as follows: CD19 - /CD20 - /CD38 + /CD56 + / cytoplasmic lambda +. Special stains demonstrated the muco-proteinaceous background to be alcian blue-positive and PAS-negative.


International Society of Neuropathology