Malignant Transformation of Mature Cystic Teratoma: Is Squamous Cell Carcinoma Different From the Other Types of Neoplasm?

OBJECTIVESMalignant transformation of mature cystic teratoma (MCT) is rare. Unlike squamous cell carcinoma (SCC) in MCT, the other types of neoplasm in MCT have not been discussed in publications. We analyzed the clinical characteristics and prognosis of the other types of neoplasm (non-SCC) compared with those of SCC. METHODSA systematic literature search of literature published from 2000 to 2017 was conducted in PubMed, Web of Science, and Scopus. We reviewed case series that included all pathological types of malignant transformation. RESULTSA total of 155 cases from 15 case series, including our cases, were included. Of the cases, 90 (58%) were SCC and 65 (42%) were non-SCC, including adenocarcinoma, carcinoid tumor, thyroid carcinoma, sarcoma, adenosquamous carcinoma, melanoma, sebaceous carcinoma, oligodendroglioma, signet ring cell carcinoma, and transitional cell carcinoma, in descending order of frequency. The mean ages of patients with SCC and non-SCC were 50.5 and 48.9 years, respectively. The mean tumor sizes were 14.7 cm in SCC and 13.9 cm in non-SCC. Surgical approaches were similar. First-line chemotherapy for epithelial ovarian cancers was the most commonly used regimen in SCC and non-SCC. Overall survival did not differ significantly, showing better prognosis in stage I and poor prognosis in stages II, III, and IV. A difference in overall survival was observed among pathological types of non-SCC. CONCLUSIONSClinical characteristics and outcomes did not differ significantly between SCC and non-SCC. However, chemotherapy regimens differed to some extent, and the possibility of difference in overall survival among pathological types of non-SCC was suggested.