Malignant Struma Ovarii: A Blinded Study of 86 Cases Assessing Which Histologic Features Correlate With Aggressive Clinical Behavior

Abstract

The clinical outcome of struma ovarii cannot be predicted based on the microscopic diagnosis of the thyroid tissue or on specific histologic features. The lack of correlation between morphology and outcome in proliferative and histologically malignant struma ovarii is striking, making the behavior of these tumors particularly unpredictable.

Struma Ovarii with Elevated Ca-125 Levels and Ascites Mimicking Advanced Ca Ovary

“…CA 125, as a tumour marker, was found to be elevated, mimicking ovarian carcinoma (only 8-10 cases have been reported so far for struma ovarii). Pre-operative evaluation with triple contrast CT /MRI [7] and increased uptake of radio-iodine 123 in ovary are pointers to diagnosis. Struma ovarii can be incidentally discovered during pelvic imaging.…”

Synchronous papillary carcinoma thyroid with malignant struma ovarii: A management dilemma

“…The pathological criteria used for diagnosing carcinoma of the thyroid gland are widely accepted as the standard for diagnosing malignant SO as well. [3] The malignant thyroid tissue may be of the papillary, follicular variant of papillary carcinoma, or the follicular pattern.…”

The lack of consensus in management of malignant struma ovarii

“…However, the definitive diagnosis is histological, although no histological feature is pathognomonic of malignant struma ovarii. Except for the lack of fibrosis and macrofolicular pattern, no single histologic feature predicts a future malignant clinical course in proliferating struma ovarii [6].…”

“…Factors that indicate an increased risk of malignant behavior of these tumors are: (1) extraovarian spread, (2) recurrence after surgery, (3) adherence to adjacent organs, (4) significant ascites (41 l), (5) struma size greater than 5 cm, and (6) presence of 450% of proliferating tissue within a teratoma [6]. However, the definitive diagnosis is histological, although no histological feature is pathognomonic of malignant struma ovarii.…”

“…We can distinguish two categories: proliferative struma (lowgrade tumor and borderline malignancy where atypia and mitosis are rare) and malignant struma [2,6].…”