NIFTP Arising In Struma Ovarii: A Rare Case Report

Struma ovarii is a rare type of ovarian teratoma distinguished by the unusual presence of thyroid tissue. This condition is challenging to diagnose on the basis of clinical manifestations or imaging studies, given the diverse clinical presentations or even absence of symptoms and no typical ultrasound feature. A definitive diagnosis is usually confirmed only postoperatively, established on histopathological findings of the resected ovary. The presence of malignant transformation is infrequent and founded on case series, papillary and follicular carcinoma are the most frequent forms. The management remains defiant with no clear guidelines. The authors report a case of a female in her 60 s, who was diagnosed with a right ovarian teratoma, incidentally found on a CT scan for surgical planning of an incisional hernia. The patient underwent laparoscopic right oophorectomy and a Rives-Stoppa technique for median incisional hernia repair. Histopathological examination revealed thyroid tissue with a focus of NIFTP. NIFTP is a thyroid neoplasm characterized by an encapsulated or clearly delimitated structure, displaying a follicular growth pattern and nuclear features similar to papillary thyroid carcinoma. To the best of our knowledge, this is the second reported NIFTP in an ovarian teratoma, being an extremely rare condition. It is associated with an excellent prognosis, therefore, after multidisciplinary evaluation, thyroid disorders were investigated but no additional therapeutic measures were considered.