Thyroid gland: tall cell variant of papillary carcinoma and papillary oncocytic carcinoma

Within the large group of thyroid papillary carcinoma some of rare subtypes have a more aggressive clinical course and less favorable prognosis.Seven cases of thyroid gland carcinomas diagnosed by ultrasound guided FNAB are presented:five tall cell variant of papillary carcinoma(TCP) and two papillary case of oncocytic carcinoma (POC), infrequent thyroid carcinomas with varying biological behavioral patterns.While the evolution of the POC is unpredictable, the TCP presents more aggressiveness than that of the classical papillary carcinoma (CPC). Both tumors were built up by true papillae lined, contrary to the CPC, by cell with abundant granular eosinophilic cytoplasm (histologically)and eosinophilic(cytologically by MGG technique).The TCP cases showed nuclei with clear chromatin, nuclear grooves and intranuclear cytoplasmic inclusions (similar to CPC) and sometimes lymphocytic infiltrate in the papillary core.In the POC the nuclei showed pleomorphism, granular chromatin and prominent nucleoli as in the traditional Huerthle cell tumors.To conclude, the importance of preoperative cytologic diagnoses of both types of neoplasms lie in their different biologic behavior, which determines the type of treatment in two entities.