A 70-year-old male has a pathologic fracture of femur. The lesion appears a lytic on X-rays film with a circumscribed punched out appearance.The curetting from fracture site is most likely to show which of the following?

Ans. is 'b' i.e. Sheets of atypical plasma cells Age of the patient along with cystic, circumscribed punched out X-ray appearance suggests multiple myelomaMultiple myeloma most often presents as multifocal destructive bone tumours composed of plasma cells throughout the skeletal system.The bone lesions appear radiographically as punched out defects, usually 1-4 cm in diameter and grossly consists of gelatinous soft red tumour masses.Microscopic examination of the marrow reveals an increased number of plasma cells which usually constitute more than 30% of marrow cellularityThe plasma cells can infiltrate the marrow diffusely or be present in sheet like masses that completely replace normal elements.Cytologic ally, the cells may be indistinguishable from normal plasma cells, but they usually show abnormal chromatin such as less clumping of nuclear chromatin, large nucleoli, lack of perinuclear clear zone, lighter blue cytoplasm and varying degrees of anaplasia.The dissociation of nuclear and cytoplasmic maturation is a distinctive feature of myeloma cells.