A 35-year-old woman has an MRI showing a well-demarcated, heavily calcified frontal lobe mass. Biopsy reveals a tumor composed of uniform cells with round nuclei, clear cytoplasm giving a 'fried-egg' appearance, and a chicken-wire vascular pattern. This tumor is most strongly associated with which combined chromosomal deletion?
- A Loss of chromosome 10q
- B Loss of chromosomes 1p and 19q ✓
- C Gain of chromosome 7 and loss of chromosome 10
- D Loss of chromosome 22q
Correct answer: B. Loss of chromosomes 1p and 19q
Explanation
The described tumor is an oligodendroglioma, characterized by round uniform nuclei with perinuclear halos (fried-egg artifact), a delicate chicken-wire capillary network, and calcifications. The hallmark molecular alteration is codeletion of chromosomes 1p and 19q, which is required for the diagnosis per WHO 2021 classification and is associated with improved chemosensitivity and better prognosis. This codeletion results from an unbalanced translocation between chromosomes 1 and 19.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.