A 15-year-old girl undergoes removal of an 18 cm predominantly solid ovarian tumour. Histology shows sheets of primitive small blue cells forming rosettes, consistent with immature neuroectodermal tissue occupying broad areas between mature cartilage and skin adnexa. Prognosis and the need for adjuvant chemotherapy in Stage IA disease depend chiefly on:

• A The proportion of yolk sac element present
• B The mitotic count in the mature cartilaginous component
• C The degree of cytological atypia in mature skin adnexa
• D The quantity of immature neuroectodermal tissue per slide ✓

Explanation

Immature teratomas are graded using the Norris system according to the amount of immature neuroectodermal tissue per low power field, ranging from grade 1 (rare foci) to grade 3 (dominant primitive tissue). Grade determines recurrence risk and whether adjuvant chemotherapy is needed even for Stage IA disease beyond grade 1. Grading does not rest on mitoses in mature components, atypia in mature tissues, or a yolk sac component, which would instead classify the tumour as a mixed germ cell tumour.

Reference: Williams Gynecology, 4th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.