Figure 3: Digital subtraction angiography in anterior projection on the left demonstrating the mass in the left parietal region being supplied by meningeal branches from the left external carotid artery. (Left) arterial phase and (Right) capillary phase.
supporting the diagnosis of amultifocal, multiplemyeloma. A CT angiogram revealed the mass to be enhancing from hyper-vascularity seen on the venous phase with associated areas of necrosis and calcifications of the adjacent tissues. The patient had a cardiac arrest and was later diagnosed with endocarditis with severe aortic regurgitation and un- derwent a valve replacement. Subsequently, the patient had a partial resection of the calvarial plasmacytoma. A follow- up MR of the brain revealed additional lytic lesions in the left parietal region with no evidence of brain meningeal or parenchyma involvement. The patient underwent radia- tion therapy to the left parietal region and was enrolled in the Southwest Oncology Group (SWOG) clinical trials and placed on Zometa, Revlimid, and Decadron. The patient was then evaluated for Autologous Peripheral Blood Stem Cell Transplantation (APBSCT), since her Karnofsky perfor- mance status had improved to 90%. The patient continues to be followed-up and remains stable at the time of this writing, six months from the identification of the calvarial mass. DISCUSSION Solitary intramedullary plasmacytoma may occur as a primarily focal entity or as the first presentation of a systemic disease, such as multiple myeloma. Nearly 57% of patients with solitary plasmacytoma eventually develop multiple myeloma. 2 Although multiple myeloma generally presents as a symptomatic multifocal process, some patients do not present overt manifestations, and the diagnosis is
made on the basis of screening laboratory tests. 3-7 Multiple myeloma is difficult to diagnose when it is manifested in the head and neck as a solitary plasmacytoma, which is an un- common manifestation and simulates other head and neck neoplastic masses. 3,4 Plasmacytomas may associate with or progress to multiple myeloma in up to 50% of patients. 5, 6 They generally appear as a bone or soft tissue tumor with mass effect, pain, weakness, fatigue, fever, and infection. 5,7 Solitary intracranial plasmacytomas are rare, with only scat- tered cases having been reported in the literature. 2 These lesions can arise from the calvarium, dura, and base of the skull and may appear as benign lesions. 4 In patients with a primary calvarial mass, the lesion may generate focal cerebral dysfunction. Calvarial lesions and most skull base plasmacytomas, being intramedullary, have a greater chance of progressing to multiple myeloma than the dural-based lesions but less than extracranial extramedullary plasmacytomas. It has been observed that all base of the skull infiltrating plasma- cytomas were associated with multiple myeloma. 8 HISTOPATHOLOGY Solitary plasmacytoma of bone (osseous plasmacytoma) is a localized tumor consisting of monoclonal plasma cells with an immunophenotypic pattern similar to plasma cell myeloma. As such, plasmacytomas typically express CD79a, CD138, and CD38 similar to normal plasma cells with aber- rant expression of CD56, suggesting a neoplastic process (67%-79% of cases) and a lack of CD19 reactivity (nearly all
J La State Med Soc VOL 166 July/August 2014 151
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