Five instances had ascites, 2 of which were with a negative cytological exam for malignant cells. Summary There has been controversy about the management of malignant SO, which is a rare entity. Malignant SO causing thyrotoxicosis is definitely even more uncommon. As clinical indications are nonspecific, other causes of thyrotoxicosis must be considered for any differential analysis. Our case is one of the very few instances ever reported. strong class=”kwd-title” KEY PHRASES: Struma ovarii, Malignant struma, Thyrotoxicosis, Follicular carcinoma, Teratoma, Ovarian tumor What Is Known about This Topic? Struma ovarii (SO) is definitely a specialized monodermal teratoma mainly composed of mature thyroid cells ( 50%), b-AP15 (NSC 687852) accounting for approximately 5% of all ovarian teratomas. Thyrotoxicosis is seen in about 8% of individuals with SO. Most SO instances are benign, with only 5-10% becoming malignant. Malignant SO causing thyrotoxicosis is very uncommon. What Does This Case Statement Add? This statement adds to the limited number of cases of malignant SO causing thyrotoxicosis. It also illustrates the controversy concerning the management of malignant SO. Intro Struma ovarii (SO) is definitely a specialized monodermal teratoma mainly composed of adult thyroid cells [1]. Thyroid cells must comprise more than 50% of the overall cells to be classified as an SO. SO accounts for approximately 5% of all ovarian teratomas [2]. Most SO instances are benign, with only 5-10% becoming malignant [3,4]. b-AP15 (NSC 687852) Due to the rarity of the malignant transformation there has been controversy concerning the management of malignant SO instances. Thyrotoxicosis is seen in about 8% of individuals with SO [5], but most instances are asymptomatic from a thyroid standpoint with the majority of patients showing with symptoms attributable to a mass effect, such as pelvic pain. In thyrotoxic individuals, serum thyroid-stimulating hormone (TSH) is definitely low and free CDC25B thyroxine (feet4) and/or triiodothyronine (T3) are elevated along with serum thyroglobulin (TG). The thyroid gland is typically not enlarged. Rarely, ladies with SO and thyrotoxicosis also have goiter [6], while the coexistence of SO with Graves’ disease offers hardly ever been reported in the literature [7,8]. Malignant SO causing thyrotoxicosis is very uncommon [9]. Here we statement a rare case of malignant SO causing thyrotoxicosis and discuss the relevant literature review. Case Statement A 64-year-old female presented with abdominal pain and progressive enlargement of the belly over a 2-month period. Her symptoms experienced in the b-AP15 (NSC 687852) beginning been attributed to irritable bowel syndrome. Abdominal ultrasonography exposed a pelvic mass and a large fluid collection. Subsequently, computed tomography (CT) of the belly and magnetic resonance imaging of the pelvis confirmed the presence of a complex right ovarian mass measuring 13 cm, and the patient was admitted for surgery. The patient’s past medical history exposed multinodular goiter, irritable bowel syndrome and nephrolithiasis. Two years prior to her current endocrinological assessment the patient had been diagnosed with thyrotoxicosis, which had been attributed to a multinodular goiter, and was treated with carbimazole. The patient, euthyroid under treatment, underwent a total abdominal hysterectomy and bilateral salpingo-oophorectomy, omentectomy and appendectomy, and multiple biopsies were taken from the Douglas pouch. No peritoneal nodules were excised. Macroscopically in the anatomical position of the right ovary, a white-gray-tan mass was observed (12 7 7 cm) with elastic homogenous regularity and focal areas of hemorrhage. Multiple sections were taken for histological exam. Microscopically, the neoplasm consisted of obvious cells having a follicular and solid pattern, slight nuclear atypia, few mitotic numbers and prominent obvious cell cytoplasm (fig. ?(fig.1).1). The tumor displayed predominately obvious cell changes (90%) and only a small portion showed SO follicles. Capsular invasion was observed as well as several vessel invasions within the tumor (fig. ?(fig.2).2). Immunohistochemical antibodies such us TTF1 (thyroid transcription element 1), anti-folate receptor 4 antibody TH6 and monoclonal anti-mesothelial cell clone HMBE1 were positive, neuron-specific enolase (NSE) was focally positive, while pan-cytokeratin and cytokeratin 19 were bad. Metastatic infiltration was observed in the biopsies taken from the Douglas pouch. The remaining ovary, uterus and appendix were free of metastasis. Capsular invasion, vessel invasion and metastasis of the neoplasm to the Douglas pouch supported the analysis of carcinoma. The final analysis was given as thyroid follicular carcinoma, obvious cell variant, arising in SO, with metastatic infiltration in the pouch of Douglas. Open in a separate windowpane Fig. 1 Thyroid follicular carcinoma (obvious cell.