Endocrine Abstracts

Introduction: Struma ovarii (SO) is a rare ovarian teratoma characterized by the presence of thyroid tissue in >50% of the tumour. Malignant transformation is rare and defined by the same histological criteria as for thyroid cancer. There is few data on the literature and treatment is controversial. The objective of this study was to describe the clinical, pathologic and treatment characteristics of women diagnosed with SO in our centre.

Methods: Retrospective analysis of the SO followed in our Institution between 2000 and 2015.

Results: A total of 13 patients were identified with a median age at diagnosis of 46 years (range 19–85). No patient had previous history of thyroid disease. In nine cases the diagnosis was made by routine imaging exams and in three cases by associated symptoms (mostly pelvic pain). CA 125 and HE4 serum levels were normal in every patient tested (four and three patients respectively). Seven patients underwent bilateral oophorectomy plus hysterectomy (with or without omentectomy or external iliac lymphadenectomy) and in six the surgical procedure was a unilateral oophorectomy. Three cases were diagnosed as malignant SO. In these cases thyroidectomy followed by radioactive iodine was performed and papillary thyroid cancer (PTC) was diagnosed in two.131I-WBS performed after surgery, showed no uptake in the pelvis in any patient. In one benign SO case, thyroid imaging and fine-needle biopsy disclosed PTC as well. During a median follow-up of 14 months (range 1–78), nine patients remained with no evidence of disease, one died with a non-related cause and one was lost to follow-up. Two of the malignant SO patients were found to have biochemical evidence of disease.

Conclusions: SO was frequently asymptomatic. Patients with malignant SO had often persistence of disease, although they had a good overall survival rate. An important proportion of these patients developed thyroid cancer.