skip to main content

Growing Teratoma Syndrome — SCE Medical Oncology MCQ

Instant feedback + full explanation. One question, done properly.

ModerateUrological CancersGrowing Teratoma SyndromeSCE Medical Oncology

A 35-year-old man with testicular cancer achieves a complete response after BEP chemotherapy. Two years later, surveillance CT shows a new growing retroperitoneal mass. AFP and HCG are normal. LDH is normal. Biopsy shows mature teratoma only. What is this phenomenon?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: E — Growing teratoma syndrome (GTS) — enlarging mature teratoma after chemotherapy with normal markers; it represents chemotherapy-induced differentiation of residual disease; treatment is surgical resection, NOT further chemotherapy

Growing teratoma syndrome is a unique phenomenon in GCT where mature teratoma enlarges progressively after chemotherapy despite normalised tumour markers. The mechanism is chemotherapy-induced differentiation of residual malignant cells into mature teratoma (which is chemoresistant). Treatment is complete surgical resection — further chemotherapy is ineffective against mature teratoma. Complications of untreated GTS include: obstruction, compression of adjacent structures, and rare malignant transformation of teratomatous elements (somatic-type malignancy).

Reference: ESMO 2024 Testicular Cancer; Logothetis et al Ann Intern Med 1982; NICE NG