The imaging findings are those of a spinal bone tumor involving the vertebras of T3 and T4 favored representing a primary bone malignancy, particularly in this age group and in the absence of a known malignancy elsewhere. At this age group, differentials would include lymphoma, sarcoma (Ewing's), or eosinophilic granuloma. Chordoma is felt unlikely differential given its distribution and signal on T2. 

Further surgical approach and biopsy have confirmed diffuse large B-cell lymphoma. B-cell is the most common type of non-Hodgkin lymphomas.

MICROSCOPY: The sections show a proliferation of atypical lymphoid cells, forming diffuse sheets. No follicular arrangement is seen. The atypical lymphocytes are medium to large in size. They have enlarged clefted and hyperchromatic nuclei, prominent nucleoli and scanty cytoplasm. The background contains occasional small lymphocytes and plasma cells. The tumor infiltrates in-between bony trabeculae, with adjacent woven bone formation. The tumor cells are CD20, PAX-5, bcl-6 and MUM1 positive. c-Myc stains about 15% of the tumor cells. Bcl-2 stains weakly less than 10% of the tumor cells. The Ki-67 index is about 90%. They are CD3, CD5, CD10, CD23, CD138, Cyclin D1, TdT, ALK-1 and EBER-CISH negative. The features are those of diffuse large B-cell lymphoma, not otherwise specified, with activated B-cell-like phenotype.

DIAGNOSIS: Diffuse large B-cell lymphoma