A 5-year-old boy presents with a rapidly enlarging mass in the right iliac fossa and abdomen. Biopsy shows sheets of intermediate-sized blasts with round nuclei, multiple nucleoli, and a starry-sky pattern produced by interspersed macrophages. Ki-67 labels essentially 100% of cells. Which molecular event is the hallmark of this tumour?

• A Dysregulation of MYC by translocation into the IgH locus, classically t(8;14) ✓
• B Overexpression of BCL6 through t(3;14)
• C Loss of TP53 with concomitant del(17p)
• D Fusion of ALK with NPM1 through t(2;5)

Explanation

This is sporadic Burkitt lymphoma, which typically presents as an abdominal mass in children outside malaria-endemic regions. Its defining lesion is translocation of MYC to an immunoglobulin locus, usually t(8;14), driving relentless proliferation reflected by the near-total Ki-67 fraction and the starry-sky pattern from tingible-body macrophages. EBV is present in almost all endemic cases but only a minority of sporadic ones. BCL6 rearrangements belong to DLBCL, not Burkitt.

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.