TY - JOUR T1 - Squamous cell carcinoma arising in a tall cell papillary carcinoma of the thyroid JF - Journal of Clinical Pathology JO - J Clin Pathol SP - 662 LP - 664 DO - 10.1136/jcp.2004.021451 VL - 58 IS - 6 AU - J Sutak AU - J S Armstrong AU - J E Rusby Y1 - 2005/06/01 UR - http://jcp.bmj.com/content/58/6/662.abstract N2 - Transformation of differentiated thyroid cancer into poorly differentiated carcinoma is rare. This report describes a case in which preoperative fine needle aspiration suggested a squamous cell carcinoma whereas needle core biopsy favoured an undifferentiated carcinoma of probable thyroid origin. Histology of the subsequent total thyroidectomy specimen revealed a biphasic tumour comprising areas of tall cell papillary carcinoma merging with moderately to poorly differentiated squamous cell carcinoma. The immunohistochemical findings are discussed in detail. ER -