Amyloid Deposition in Papillary Thyroid Carcinoma: An Overlooked Event?
Andre Pinto, Vania Nose. University of Miami / Jackson Health System, Miami, FL
Background: Amyloid infiltration in the thyroid is a finding almost restricted to medullary carcinoma. It can also be rarely seen in patients with systemic amyloidosis and amyloid goiter. However, only a handful of cases of papillary thyroid carcinoma (PTC) with amyloid-rich stroma have been reported in the literature.
Design: All cases (paraffin-embedded, hematoxylin & eosin stained slides) of PTC (106 specimens) and benign thyroid (109) from one of our institutions, of a one year period, were reviewed. The cases on which the stroma contained deposits of amorphous, acellular and eosinophilic material characteristic of amyloid, congo-red stain was performed and the slides were analyzed under polarized light. The clinical histories of the positive cases were extensively reviewed to exclude patients with primary or secondary systemic amyloidosis.
Results: We found seven (7) patients with amyloid deposition in the thyroid in association with PTC (age ranging from 53 to75 years old), and four (4) cases of benign pathologies (age ranging from 26 to 64 years old; end-stage thyroid- 2 cases, follicular adenoma-1 case, hyperplastic nodule with adenomatous changes- 1 case) diagnosed by the typical apple-green birefringence under polarized light microscopy. Among the positive cases, none of the patients had a known systemic amyloidosis. Most patients were male (7/11), and most of the neoplastic cases had morphological features of a more aggressive behavior (lymphovascular invasion in 5/7; and the variants: diffuse sclerosing-3, tall cell- 1, columnar cell- 1 and oncocytic follicular- 1).
Conclusions: We present the largest series of PTC with amyloid-rich stroma. The relationship between this finding and its real incidence, and if this represents an evidence of a more aggressive behavior when associated with papillary carcinoma, are still unclear statements. However, this study indicates that this finding is not exclusive of medullary carcinoma, since it can be present in other thyroid neoplasms and in benign pathologies. Better characterization of the amyloid will help understand the nature of this phenomenon.
Tuesday, March 20, 2012 1:00 PM
Poster Session IV # 35, Tuesday Afternoon