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The "mini brain" appearance of plasmacytoma in the appendicular skeleton
N Subhas1, T W Bauer, M J Joyce
1Department of Diagnostic Radiology, Cleveland Clinic, 9500 Euclid Ave. A21, Cleveland, OH, 44195, USA. subhasn@ccf.org
Abstract:
We report on the case of a 70-year-old woman presenting with right hip pain. Radiographs of the right hip demonstrated a well-defined large lytic lesion in the proximal right femur, with prominent trabeculae situated peripherally and extending into the lesion in a "spoke-wheel" pattern. Magnetic resonance imaging (MRI) demonstrated solid enhancing marrow-replacing lesion, with intervening linear nonenhancing areas of low T2 signal intensity. The MRI appearance resembled that of a small brain or "mini brain". Biopsy specimen demonstrated predominantly mature plasma cells, with occasional admixed immature forms. A diagnosis of plasmacytosis, consistent with myeloma, was made. This case illustrates a rare but seemingly characteristic "mini brain" appearance of plasmacytoma, which, to date, has only been reported in the spine and has not been observed in other bony lesions.
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