What happened, in summary

A 53-year-old woman sought care for abdominal pain and urinary retention. Imaging found a very large ovarian cyst measuring about 13 cm, with an area of thickening in the cyst wall. Doctors initially thought malignant transformation of a dermoid cyst was unlikely, and scans showed no distant spread.

Forty-two days after presentation, she underwent surgery. The cyst wall was thickened and attached to nearby pelvic structures, so tissue was tested during the operation. Frozen-section pathology showed invasive squamous cell carcinoma arising in the ovarian mature cystic teratoma. Surgeons then performed a total abdominal hysterectomy, removed both ovaries and fallopian tubes, and removed the omentum. Lymph node surgery was not performed because the cyst wall was firmly attached around the surrounding nodes.

Final pathology confirmed well-differentiated squamous cell carcinoma arising in the dermoid cyst, with no definite vascular invasion. The cancer was classified as Stage I. At 21 months after surgery, she remained free of clinically identifiable recurrence. The case shows the value of examining suspicious thickened areas during surgery when a dermoid cyst has unexpected features.