Follicular Adenomas. (a) Photomicrograph of a follicular adenoma (hematoxylineosin, ×LP) (b) A follicular adenoma, immunostaining for cytokeratin 19, focal positive (1+) (IHC, ×LP). Cytokeratin 19 immunoreactivity in the diagnosis of papillary thyroid carcinoma: Bose D, Das RN, Chatterjee U, Banerjee U - Indian journal of medical and paediatric oncology : official journal of Indian Society of Medical & Paediatric Oncology (2012). Not Altered. CC.