A 58-year-old woman had a dermoid cyst removed 12 years ago. She now returns with ascites, a fixed pelvic mass and biopsy-proven squamous cell carcinoma arising within residual ovarian tissue at the previous site. Which statement about malignant transformation in mature cystic teratoma is CORRECT?
- A It occurs only in premenopausal women
- B It occurs in about 10 percent of cases, and thyroid carcinoma is the most frequent type
- C It occurs in about 1 to 2 percent of cases, and squamous cell carcinoma is the most frequent type ✓
- D Adenocarcinoma of intestinal type is the most common transformed element
Correct answer: C. It occurs in about 1 to 2 percent of cases, and squamous cell carcinoma is the most frequent type
Explanation
Malignant transformation complicates approximately 1 to 2 percent of mature cystic teratomas, typically in older postmenopausal women, and the vast majority are squamous cell carcinomas arising from the squamous epithelium lining the cyst. Thyroid malignancy within struma ovarii is far rarer, and intestinal-type adenocarcinoma is an uncommon transformed element, ruling out options B and D.
Reference: Shaw's Textbook of Gynaecology, 17th ed.
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Written and medically reviewed by the StethoPrep medical team.