Plasma cell myeloma with intracytoplasmic and extracellular rhomboid crystalline inclusions. (a and b) Bone marrow aspirate stained with Wright-Giemsa. Note abundant rhomboid crystals present in the extracellular space (a; arrows) and intracytoplasmic in plasma cells (b; arrow-heads). (c) H&E stain of bone marrow biopsy section showing prominent rhomboid crystals (arrow). (d) Immunohistochemistry for lambda-chain highlights monotypic plasma cells with positive stain of the extracellular crystals (arrow). Bar 200 μm (a), 20 μm (b), and 50 μm (c and d).
Matoso et al. Diagnostic Pathology 2010 5:6 doi:10.1186/1746-1596-5-6