[1175] Natural History of Biologically Malignant Struma Ovarii: Analysis of 27 Cases with Extra-Ovarian Spread

R Shaco-Levy, SM Bean, RC Bentley, SJ Robboy. Soroka Medical Center, Beer-Sheva, Israel; Duke University Medical Center, Durham, NC

Background: Biologically malignant struma ovarii is exceedingly rare. Most histologically malignant cases reported had a benign clinical course. This study analyzes 27 biologically aggressive cases and reports clinical courses, histological features and prognosis based on long-term follow-up in many cases exceeding 20 years.
Design: Cases were considered biologically malignant if there was: (1) extra-ovarian spread at presentation, (2) infiltration of the ovarian serosal surface, or (3) recurrence after initial surgery. Strumas composed of proliferative hypercellular thyroid tissue were classified as follicular adenoma. The diagnosis of follicular carcinoma required the presence of vascular invasion. Tumors with true papillary structures along with optically clear “Orphan Annie” nuclei, nuclear overlap, grooves and pseudo-inclusions were classified as papillary carcinoma.
Results: Extra-ovarian spread was evident at presentation in 17 patients. The malignant nature of the other 10 tumors became apparent only after they recurred. The tumors measured 5-24.5 cm and were >50% thyroid tissue in all but 2 cases. The microscopic diagnosis was follicular adenoma in 17 cases (63%), papillary carcinoma in seven (26%), unremarkable thyroid tissue in two (7%), and follicular carcinoma in one (4%). Generally, the clinical course was protracted, with long-term survival documented in most patients. Factors predictive of poor prognosis were large size (≥10 cm), strumal component > 80%, and extensive papillary carcinoma, especially with solid areas, necrosis and ≥5 mitoses per 10 HPF. Follow-up for all patients was 1.5-33 years (mean=13.5 years). On last follow-up three patients (11%) had no evidence of disease, nine (33%) were alive with disease, five (19%) died of other causes, and 10 (37%) died of disease. Death from disease occurred 1.5-32 years after diagnosis (mean 14 years). Recurrence was seen 2 months to 29 years after initial surgery (mean=7 years).
Conclusions: Biologically malignant struma ovarii generally has a protracted clinical course. Long term survival may occur even with metastatic disease. Some patients experience rapid disease course with death shortly after diagnosis. Factors indicative of aggressive clinical course are large tumor size, >80% strumal tissue, and extensive papillary carcinoma histology, especially with anaplastic features. As recurrences may occur more than a decade following diagnosis, long-term follow-up required.
Category: Gynecologic & Obstetrics

Wednesday, March 24, 2010 1:00 PM

Poster Session VI # 173, Wednesday Afternoon


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