Extramedullary plasmacytoma of the dura mimicking meningioma

Abstract

In December 2005, a 59-year-old man presented at ourNeurosurgery Department with a 2-month history ofamnesia and gait disturbance. A solid mass lesion wasdetected in the right temporal region on magnetic reso-nance imaging (MRI), presumed to be a meningioma(Fig. 1). He underwent surgery via a right temporal frontalcraniotomy and partial resection of the mass. Biopsy of themass demonstrated a densely cellular tumor composed ofplasma cells, positive for IgG and kappa light chain(Fig. 2), and negative for lambda chain, CD56 and cyclinD1. These findings were consistent with intracranialplasmacytoma.No additional sites of plasmacytoma were identified oneither computed tomography or bone scintigraphy, and bonemarrow plasmacytosis was absent (1.8% plasma cells,morphologically normal), and bone marrow cells showed anormal karyotype. Serum immunoglobulin levels werealmost normal (IgG 1,374 mg/dL, IgA 443 mg/dL, IgM54 mg/dL, IgE 81 IU/mL, IgD 7.6 mg/dL), and postopera-tive serum protein immunoelectrophoresis showed a smallM-component only (IgG-j). Urine Bence-Jones protein wasnot detected. Other organopathies, such as nephropathy,hypercalcemia and bone region, were absent. Thus, a diag-nosis of extramedullary plasmacytoma was made accordingto the classification of the International Myeloma WorkingGroup (IMWG) [1]. He underwent external beam radio-therapy to the brain at a dosage of 50 Gy, which resulted inthe disappearance of the remaining tumor region.In January 2007, he developed hoarseness and thoracicpain. Since CT scans demonstrated new masses at other sites(rib and vertebral bones), he was diagnosed with diseaseprogression. Laboratory findings showed an increased totalserum protein of 8.6 g/dL, IgG 3,629 mg/dL, and serumprotein immunoelectrophoresis revealed an evidentM-component of IgG-j. Bone marrow examination showedno evidence of plasmacytosis (2.4% plasma cells, withoutatypia) and chromosomal analysis revealed a normalkaryotype. Thereafter, he received several courses of che-motherapy with vincristine, doxorubicin and dexametha-sone. Despite treatment, regrowth of the mass was observed.He refused further therapy and was discharged from ourhospital.Patients with a solitary dural plasmacytoma have beenreported with a female predominance of 84% and a meanage of 50.2 years. Clinically, combination therapy includ-ing surgical resection followed by at least 50 Gy radio-therapy is recommended, and long-term survival has beenobserved. On the other hand, patients with myelomatousmeningeal involvement have shown an extremely poorprognosis despite intensified treatment, including intrathe-cal and/or systemic chemotherapy and cranial radiotherapy[2]. Our patient showed a recurrence almost 1 year after theinitial diagnosis. We consider that postoperative radio-therapy was delayed by about 2 months because of inten-sive care, which might have caused the early recurrence.