PMC3768339_01
Magnetic resonance image demonstrating left temporal lobe enhancing lesion. T2-weighted image postgadolinium showing a peripherally enhancing mass with mass with edema producing mild ventricular compression.
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F1
Magnetic resonance imaging revealed a 3.5 x 1.3 x 1.9 cm contrast enhancing lesion of the left temporal lobe with a mild midline shift [Figure 1].
Brain lesion with crystal storing histiocytosis. (a) Numerous histiocytes contain rhomboid and needle-like kappa light chain restricted crystals are inconspicuous with standard stains (Hematoxylin and eosin, original magnification x200). (b) Crystal deposition is apparent with periodic acid Schiff stain (PAS stain, original magnification x200)
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F2
The sections revealed a fibrotic lesion with an extensive chronic inflammatory infiltrate of CD138-immunoreactive plasma cells, CD68-immunoreactive macrophages and monocytes and S100-immunoreactive histiocytes [Figure 2a]. There were numerous periodic acid-Schiff (PAS) staining rhomboid crystals and granular material that was predominantly intracellular but also extracellular [Figure 2b].
Brain lesion demonstrating lambda light chain immunofluorescence. Crystals show lambda but not kappa immunoflourescence. (Original magnification x600)
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F3
To evaluate whether immunoglobulin expression was predominantly one type, additional immunoflourescence and in situ hybridization were performed. These demonstrated overwhelmingly lambda light chain restriction [Figure 3].
Electron microscopy. Histiocytes show intracellular rhomboid and needle-like inclusions. (Original magnification x10,000)
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F4
Electron microscopy revealed numerous intracellular but also extracellular rhomboid and diamond-shaped crystals [Figure 4].