The Clinical and Pathological Characteristics of Malignant Struma Ovarii: An Analysis of 144 Published Patients

Use of BRAF mutation in papillary thyroid cancer (PTC) has the potential to improve risk stratification of this cancer. The objective of the study was to investigate the prognostic value of BRAF mutation in patients with PTC. In a multicenter study of 219 PTC patients, data on their clinicopathological characteristics and clinical courses between 1990 and 2004 were retrospectively collected, and their tumor BRAF mutation status was determined. Associations of BRAF mutation with initial tumor characteristics and subsequent recurrence were analyzed. Relationships between the BRAF mutation status and clinicopathological outcomes, including recurrence, were measured. We found a significant association between BRAF mutation and extrathyroidal invasion (P < 0.001), lymph node metastasis (P < 0.001), and advanced tumor stage III/IV (P = 0.007) at initial surgery. This association remained significant on multivariate analysis, adjusting for conventional clinicopathological predictors of recurrence excluding the histological PTC subtype, but was lost when the tumor subtype was included in the model. BRAF mutation was also significantly associated with tumor recurrence, 25 vs. 9% with and without mutation, respectively (P = 0.004), during a median of 15 (interquartile range, 3-29) months of follow-up. This association remained significant on multivariate analysis adjusting for conventional clinicopathological predictors of recurrence, even including the PTC subtype (odds ratio, 4.0; 95% confidence interval, 1.1-14.1; P = 0.03). BRAF mutation was even an independent predictor of recurrence in patients with stage I/II disease, 22 vs. 5% with and without BRAF mutation, respectively (P = 0.002). BRAF mutation was also more frequently associated with absence of tumor I-131 avidity and treatment failure of recurrent disease. In patients with PTC, BRAF mutation is associated with poorer clinicopathological outcomes and independently predicts recurrence. Therefore, BRAF mutation may be a useful molecular marker to assist in risk stratification for patients with PTC.

Malignant struma ovarii is a rare type of germ cell tumor that is most often diagnosed postoperatively. The natural history and optimal treatment regimen for the disease are essentially unknown due to the small numbers of published cases. A 32-year-old woman presented with pelvic pain and an ovarian mass that was ultimately treated by total abdominal hysterectomy/bilateral salpingo-oophorectomy. Postoperatively, she was diagnosed with a malignant struma ovarii. The patient was subsequently treated with thyroidectomy and I(131) ablation and is currently disease free. A Medline literature search was performed and clinical data from 23 additional cases were compiled. In this review of 24 cases, 16 patients were followed conservatively postoperatively while 8 received varied additional therapy (4 with I(131)). There were 8 recurrences and all occurred in the conservatively managed patients. I(131) for recurrent disease provided an initial complete response in 7 women. Treatment with thyroidectomy and I(131) should be considered in the first line of management for malignant struma ovarii.

Struma ovarii that display extraovarian spread or later recurrence is exceedingly rare. Among 88 patients with "malignant" struma ovarii followed for prolonged periods, several features helped to predict the adverse clinical course. Adhesions (graded 2 to 4+), peritoneal fluid (> or =1 L) or ovarian serosal rent were worrisome features, occurring in 74% of 27 biologically malignant tumors but only 10% of 61 clinically benign tumors. The size of the strumal component rather than the overall size of the ovarian teratoma also had some predictive value. Tumors with a strumal component or =12 cm were clinically malignant. Except for a papillary pattern or poorly differentiated cancer, no microscopic feature reliably predicted the clinical outcome, including those typically associated with malignancy in primary thyroid tumors. Among the consult cases, 7% with histologic follicular adenomas and 29% with papillary carcinomas were clinically malignant. Unequivocal vascular invasion was rare, precluding assessment of its effect. Optically clear nuclei, when extensive, were useful to diagnose papillary carcinoma, but were present nevertheless in smaller numbers in both macrofollicular and microfollicular adenomas. Eight tumors confined initially to the ovary (stage 1) recurred. Papillary carcinomas recurred earlier (average 4 y) than follicular adenomatous neoplasms (average 11 y, range: 1-29 y). Overall, the survival rate for all patients was 89% at 10 years and 84% at 25 years, indicating the need for routine long-term follow-up.