Figure 2.

Histopathological examination of biopsy from corpus vertebrae. The figure demonstrates the biopsy from the patient’s corpus vertebrae L1. (A) Hematoxylin-eosin stain in low magnification demonstrating bone repair and bone marrow with the absence of organized hematopoiesis and maximal infiltration by histiocytes. (B) Hematoxylin-eosin stain in higher magnification demonstrating histiocytes with intracellular amorphous material. (C) Immunohistochemical staining for kappa light chain, demonstrating positivity in the histiocytes (brown color). (D) Electron microscopy, low magnification, showing bright intracellular material (left) and high magnification, showing no fibrils but spread tiny tubules (right).