Background and purpose: Struma ovarii is a rare tumor

especially with extraovarian spreading. The study aimed to investigate the clinical and pathological features

diagnosis and differential diagnosis of ovarian goiter. Methods: Clinical and pathological features of 14 cases of benign and malignant ovarian goiter were observed. Immunohistochemical EnVision staining

PCR-DNA sequencing and review of related literature were also used. Results: In 14 cases of benign and malignant ovarian goiter

the average age of onset is 45.6 years (18–71 years old)

and pelvic tumor is the main clinical manifestation. According to the related literature of diagnostic criteria

12 cases are struma ovarii

which is consisted of hyperplasia of the thyroid tissue under microscopic examination

1 case is malignant struma ovarii

which is papillary thyroid carcinoma by microscopic presentation

and 1 case is highly differentiated follicular carcinoma of ovarian origin (HDFCO)

which is histological benign by microscopic presentation

but is malignant by biological behavior. Conclusion: Struma ovarii is a rare ovarian mondemal teratoma

with low rate of malignant change and beyond ovarian lesions disseminated microscopic histological benign struma ovarii is lower incidence

which has unique clinical and pathological features. Comprehensively considering the related literatures

this study indicates that the disease is in accordance with HDFCO. Struma ovarii prognosis is good

and should be differentiated from carcinoid and granular cell tumor.