Clinical history: 58 y/o female with large unilateral ovarian cyst
What is your diagnosis?
Discussion and answer
Diagnosis: Squamous cell carcinoma arising in ovarian mature cystic terratoma
Mature cystic terratoma is the most common ovarian tumour (20–40%) and the most prevalent germ cell tumour, accounting for the vast majority of all germ cell neoplasms. It may be derived from any of the three embryonic layers.
These tumours are frequently < 10 cm in size, typically have a smooth external surface, and are cystic on cut section with abundant hair and sebaceous material. A rounded, white nodule containing bone or teeth is often noticed protruding from the cyst wall (Rokitansky protuberance).
The tumours are composed entirely of mature tissues with an organized arrangement that tends to simulate the composition of various normal organs. Skin and its appendages, glia, choroid plexus, peripheral nervous tissue, fat, cartilage, smooth muscle, respiratory and gastrointestinal epithelium are the most common tissues (picture 1 and 2).
Benign tumours and secondary malignancies may develop within mature cystic teratomas, the latter with a frequency of approximately 2%, more commonly invasive squamous cell carcinoma, followed by adenocarcinomas, small cell carcinoma, sarcomas, and malignant melanoma. They are typically seen in postmenopausal women (picture 3 and 4 showing invasive squamous cell carcinoma).