A hypercellular lesion replacing the normal marrow space, characterized by a rather monomorphic infiltrate, dominated by sheets of medium-sized, mononuclear cells possessing pale, slightly eosinophilic cytoplasm. The nuclei of these cells are irregular and exhibit fine chromatin and inconspicuous nucleoli. Intimately admixed within this proliferation is residual bone marrow element Additionally, the biopsy contains fragments of benign hyaline cartilage and irregular trabeculae of woven bone rimmed by active osteoblasts; these mesenchymal elements appear reactive in nature Marker study is mandatory to characterize the infiltrate (CD20, CD3, CD30, CD10, CD79a, TdT and Ki-67).
Known case of chronic anemia under work-up, with multiple bone cystic lesions and pathological fracture.
Bone fragments collectively measured 1.7x1.5x0.7cm, totally embedded.
Tibial lesion, biopsy: