A 16-year-old girl undergoes removal of a 20 cm solid-cystic ovarian tumour. Histology shows fetal tissues along with foci of primitive neuroectoderm forming neural tubes. The tumour is classified as an immature teratoma. On what basis is its histological GRADE assigned?

• A Number of germ layers represented
• B Quantity of immature neuroectodermal tissue per microscopic field/slide ✓
• C Mitotic count per 10 high power fields alone
• D Presence of capsular breach

Explanation

Immature teratomas are graded (Norris system) by estimating how much primitive neuroepithelial tissue is present, since the volume of immature neural elements correlates with risk of recurrence and metastasis and guides the decision for adjuvant chemotherapy. Grade 1 has rare foci limited to one slide per slide examined, while grades 2 and 3 have increasing amounts. Capsular rupture affects staging, not grading.

Reference: Berek and Novak's Gynecology, 16th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.