[579] Immunohistochemical Subclassification of Thyroid Tumor with Prominent Hyalinizing Trabecular Pattern.

Sarah Lee, Ja Seung Koo, Soon Won Hong. Yonsei University College of Medicine, Seoul, Korea

Background: In surgical pathology practice, thyroid tumors with hyalinizing trabecular pattern are occasionally noted. The purpose of this study was to investigate immunohistochemical characteristics of 12 cases of thyroid tumor with prominent hyalinizing trabecular pattern (TTHTP).
Design: A retrospective review of all patients with a diagnosis of thyroid tumor with hyalinizing trabecular pattern who underwent surgery at Severance Hospital from January 2000 to December 2008 was undertaken. The criteria of TTHTP in this study was defined as thyroid tumor showing more than 90% hyalinizing and/or trabecular pattern without definitely papillary or follicular architecture. The various immunohistochemical stains were applied to 12 cases of TTHTP, and the clinicopathologic features were evaluated.
Results: The mean tumor size was 2.1 cm (range; 0.5-6.0 cm). PTC was synchronously identified in 5 cases which showed contralateral PTC in 3 cases and bilateral PTC in 1 case. One patient demonstrated bone metastasis. All TTHTPs were positive for TTF-1 and thyroglobulin. Chromogranin A, synaptophysin and p63 were negative in all TTHTPs. The same six (50.0%) cases showed expression of CD56 and Ki-67. Out of these 6 cases, 4 cases satisfied the strict criteria of Carney. CK19 and galectin-3 was positive in 2 and 5 cases, respectively.
Conclusions: All TTHTPs meeting the criteria of Carney histologically were HTT, and TTHTP which did not satisfy the criteria of Carney could be subclassified according to the results of immunohistochemistry into HTT type [Ki-67 (+) and CD56 (+)], PTC type [CK19 or galectin-3 (+)/Ki-67 (-) and CD56 (-)], and null type [Ki-67 (-), CD56 (-), CK19 (-) and galectin-3 (-)].
Category: Endocrine

Tuesday, March 1, 2011 1:00 PM

Poster Session IV # 34, Tuesday Afternoon


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