ABSTRACT
Thyroid cancer is the commonest endocrine malignancy and is the second most common cancer affecting young females in Oman. The diagnosis of Papillary Thyroid Carcinoma [PTC] is based primarily on histologic architecture and nuclear morphology in routine Haematoxilin and Eosin [H and E] stained slides. Whenever in doubt, immunohistochemistry may be helpful. This retrospective study included 115 cases of PTC diagnosed at a tertiary care center in Oman over 10 years period, from 2001 to 2010. Slides and blocks of these cases were retrieved from the pathology laboratory. Ninety five [95] were females and 20 were males. Papillary Thyroid Carcinoma [PTC]was most commonly seen in the 20 - 50 years of age. The commonest morphologic variant seen in this population was classical papillary variant in 44/115 [38%] followed by papillary micro-carcinoma [n=30/115, 26%] and follicular variant of papillary carcinoma [n=18/115, 15.6%]. Out of the 30 micro-carcinoma cases, 18 were diagnosed incidentally in thyroids operated for multi-nodular goiter. Immunohistochemical marker CK-19 was positive in 29/31, HBME-1 and HMW-CK in 15/15 cases; CEA was in one case where it was reported negative. Immunohistochemical stains were useful in cases with atypical /doubtful morphology