[451] FNAB of Secondary Neoplasms of the Thyroid Gland: A Multi-Institutional Study of 60 Cases.

He Wang, Paul J Michaels, Edmund S Cibas, Kamal Khurana, Syed Z Ali, Massimo Bongiovanni, Celeste N Powers, William C Faquin. Massachusetts General Hospital/Harvard Medical School, Boston; Brigham and Women's Hospital/Harvard Medical School, Boston, MA; Institute of Pathology, Locarno, Switzerland; Virginia Commonwealth University, Richmond; John Hopkins University, Baltimore, MD; SUNY Upstate Medical University, Syracuse, NY

Background: Secondary neoplasms of the thyroid gland, either metastatic from a known primary site or from direct extension of a perithyroidal tumor, are rare. While a majority of secondary tumors can be readily diagnosed by fine needle aspiration biopsy (FNAB) based upon an associated clinical history and characteristic cytologic features, some secondary tumors can present a diagnostic challenge.
Design: We report one of the largest FNAB cohorts of 60 secondary thyroid neoplasms from 6 tertiary medical centers in the United States and Europe. All initial diagnoses were rendered by FNAB and correlate with clinical, cytologic, and ancillary study findings.
Results: Secondary thyroid tumors in our series were more frequent in women (n=35), and the average patient age was 59 years (range: 7-79 years). Based upon tumor type, squamous cell carcinoma (n=21) was the leading secondary thyroid neoplasm, followed by adenocarcinoma (n=12), renal cell carcinoma (n=7), melanoma (n=5), and non-Hodgkin lymphoma (n=4). Other rare secondary tumors in our series included adenoid cystic carcinoma, Hodgkin lymphoma, fibrosarcoma, liposarcoma, and leiomyosarcoma. Of the metastatic carcinomas, 20% originated in the kidney, 13% in the lung (3 squamous cell carcinomas and 5 adenocarcinomas), 8 % in the breast (5 cases) and 5% in the colon (3 cases). Eighty percent of the secondary neoplasms were accurately diagnosed by FNAB. Diagnostic difficulties occurred with adenoid cystic carcinoma and renal cell carcinoma because of its resemblance to primary oncocytic thyroid tumors. When material was available, immunohistochemical stains and flow cytometry were useful ancillary studies.
Conclusions: Secondary thyroid neoplasms are rare and can present diagnostic difficulties especially among tumors such as renal cell carcinoma which can mimic a primary thyroid tumor.
Category: Cytopathology

Wednesday, March 2, 2011 1:00 PM

Poster Session VI # 52, Wednesday Afternoon


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