Unexpected Malignancy: Squamous Cell Carcinoma Arising in an Ovarian Mature Cystic Teratoma Diagnosed Postoperatively.

Although mature cystic teratomas (MCTs) of the ovary are typically benign, their rare malignant transformation (MT) into squamous cell carcinoma (SCC) represents a diagnostic and therapeutic challenge. Preoperative imaging frequently misleads clinicians by suggesting a benign lesion, and the malignant component is usually identified only after histopathological evaluation. Reporting such cases is valuable to raise awareness of this unusual entity and to emphasize the need for vigilance in the management of ovarian teratomas, particularly in women beyond reproductive age. We report the case of a 65-year-old woman in whom imaging suggested a benign teratoma, but histology revealed SCC, underlining the diagnostic challenge and the importance of awareness of this rare but clinically significant transformation.