FNA cytology is a sensitive, specific, and accurate initial diagnostic test for the evaluation of patients with thyroid swellings.

TTF-1 achieved moderate sensitivity, and high specificity in the diagnosis of AC, while P63 was highly sensitive and specific for the diagnosis of SCC. Immunocytochemistry raised the sensitivity and specificity of FNAC in diagnosing AC and SCC using TTF-1 and P63, respectively.

Napsin-A, and Desmocollin-3 were sensitive and specific markers for the diagnosis of AC and SCC, respectively. Both markers allowed classification of 54/60 cases into either AC or SCC.

Both markers were sensitive and specific for diagnosis of PDA. The staining pattern for S100P was easier to evaluate than IMP3.

RCPath reporting system for thyroid FNAC is clinically applicable and can be used for differentiation between benign cases needing observation and follow up on one hand, and malignant cases requiring surgical intervention on the other. The least inter-observer agreement (moderate agreement) was detected for Thy3a, Thy3f and Thy4 categories, necessitating multidisciplinary team meeting before any clinical decision.