Primary strumal carcinoid tumor of the ovary arising from a heterochronous struma ovarii in young female patient

Primary ovarian carcinoid tumors are extremely rare. Ovarian strumal carcinoid is usually derived from mature cystic teratoma, an ovarian germ cell tumor composed of two distinctive components characteristic thyroid tissue intermixed with a carcinoid tumor. The incidence of stromal carcinoid tumor is accounting for 0.3-1% of all ovarian tumors and 3% of all mature teratomas. Herein, we report a 25-year-old female presented with severe abdominal pain. She had right struma ovarii after Laparoscopic-Assisted Ovarian Cystectomy (LAOC) procedure one year ago. The sonography of abdomen images study demonstrated a well capsulated cystic mass measured up to 11 cm in dimension. The mature cystic teratoma was the first diagnostic possibility. She underwent the laparoscopy-assisted left ovarian cystectomy. Histopathological and immunohistochemical examinations confirmed strumal Carcinoid Tumor of the Ovary (SCTO) arising from strum ovarii in the left ovary. She was recovered well and was still asymptomatic after two years follow-up. In conclusion, we first describe the primary SCTO arising from a heterochronous struma ovarii. The symptoms of SCTO are usually non-specific and misleading. Therefore, it is important to fully understand the characteristics, diagnosis and management of SCTO. Diagnosis should be confirmed by pathology and immunohistochemistry, and clinically metastatic carcinoid should be excluded.