[1253] Long Term Follow-Up of Patients with Classic and Follicular Variant of Papillary Thyroid Carcinoma: A Comparative Study

K Shafique, MB Flanagan, KT Montone, VA LiVolsi, ZW Baloch. UPENN Medical Center, Philadelphia, PA; West Virginia University, Morgantown, WV

Background: The two most common variants of papillary thyroid carcinoma (PTC) are classic variant (PTC-CV) and follicular variant (PTC-FV). Both PTC-CV and PTC-FV can present as completely or partially encapsulated or un-encapsulated tumors. The encapsulated PTC is often associated with an excellent prognosis. The purpose of this study is to compare the clinicopathologic features and long-term follow-up of PTC-CV and PTC-FV with special regards to the encapsulated form.
Design: A cohort of 114 cases including 58 PTC-CV and 56 PTC-FV were selected from the computerized pathology files at the Hospital of University of Pennsylvania. Clinico-pathologic data and follow-up (serum thyroglobulin measurements, radiologic studies and/or additional tissue sampling) through present date were extracted from medical records.
Results: The median patient age at initial diagnosis was 46 years for PTC-CV with a male to female ratio of 16:42 and 45.5 years for PTC-FV, with a male to female ratio of 13:43. Complete tumor encapsulation was seen in 40 (69%) PTC-CV and in all (100%) PTC-FV cases. A higher rate of tumor capsule invasion(CI) lymphovascular invasion(LVI), extrathyroidal extension (ETE) and lymph node metastases (LN-mets) was seen in PTC-CV as compared to PTC-FV; CI 26% vs. 18%, LVI 17% vs. 4%, ETE 19% vs. 7% and LN-mets 67% vs. 29%.Clinical, radiologic and/or pathologic follow-up was available in 36 (62%) PTC-CV and 34 (61%) PTC-FV cases. The median follow-up for PTC-CV was 10-years and PTC-FV was 9-years. Tumor recurrence was found in 11(11/36-31%) PTC-CV and 2 (2/34-6%) PTC-FV cases. Distant metastasis occurred in 3 (5%) of PTC-CV and 1(1.7%) PTC-FV case; of these two cases of PTC-CV were encapsulated tumors which showed CI, LVI and LN-mets.
Conclusions: Clinical follow-up was available in 62% of PTC-CV and 61% PTC-FV patients. In our experience, encapsulated PTC-FV is an indolent disease as compared to encapsulated PTC-CV, with only 1/34 (3%) patients with long-term follow-up showing distant metastases.
Category: Head & Neck

Wednesday, March 24, 2010 9:30 AM

Poster Session V # 167, Wednesday Morning


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