A 9-year-old boy from a rural area presents with rapid enlargement of the right mandible over 6 weeks. Biopsy shows sheets of intermediate-sized lymphoid cells with round nuclei, multiple small nucleoli, and numerous tingible body macrophages scattered among apoptotic tumour cells. Ki-67 proliferation index exceeds 95%. The underlying oncogenic event involves which gene?

• A Constitutive JAK2 activation by V617F mutation
• B BCL6 translocated to the immunoglobulin heavy chain locus
• C MYC translocated to the immunoglobulin heavy chain locus ✓
• D Loss of TP53 by 17p deletion

Explanation

The jaw mass in a child, starry sky appearance from tingible body macrophages, near-total Ki-67 staining, and apoptosis are hallmark features of endemic Burkitt lymphoma, caused by t(8;14) placing MYC under the Ig heavy chain promoter, driving uncontrolled growth. BCL6 rearrangements occur in DLBCL. JAK2 V617F is a myeloproliferative lesion, and 17p deletion is seen in CLL and various advanced cancers.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.