title: Cytokeratin 5/6 and P63 immunophenotype of thyroid lymphoepithelial complexes.
abstract: Thyroid lymphoepithelial complexes (LECos) are rare, being reported in lymphoma, Graves-Basedow disease, Hashimoto thyroiditis, pericarcinomatous thyroid or in the context of branchial cleft-like cysts. Here we report immunohistochemical expression of cytokeratin 5/6, P63 and TTF1 in 6 cases of thyroid LECos. Two cases had carbimazole treatment for hyperthyroidia and Graves disease. Anti-thyroglobulin, -thyroperoxidase or -TSH antibodies were detected in 4 cases. NSAID or poviodone iodine allergy were present in 2 cases. The treatment consisted in total thyroidectomy or lobectomy. Microscopy showed nodular goiter and focal lymphocytic thyroiditis. Basaloid LECos were seen in all thyroids while squamoid LECos in 2. Associated lesions were papillary thyroid microcarcinoma (2 cases), solid cell nest, thyroglosal duct remnant, lymphoepithelial cyst and thymus-parathyroid unit (one case each). Cytokeratin 5/6 was expressed in both squamoid and basaloid LECos along with P63. TTF1 expression was faint or absent. In conclusion LECos may occur in the context of autoimmune thyroiditis or of a specific immune susceptibility background. The expression of CK5/6 and of P63 suggests a squamous differentiation including in the basaloid LECos. The etiologic relevance of these immunostainings remains limited although rather suggestive of a metaplastic process than of migration-abnormalities.
authors.affiliation: APHP GHU Avicenne, Universite Paris Nord Sorbonne Cite, France. Electronic address: adriana.handra-luca@hotmail.com.
authors.forename: Adriana
authors.initials: A
authors.lastname: Handra-Luca
authors.affiliation: Virginia Commonwealth System, Richmond, VA, USA. Electronic address: ema.dragoescu@vcuhealth.org.
authors.forename: Ema
authors.initials: E
authors.lastname: Dragoescu
mesh_terms: D000328:Adult; D000368:Aged; D002291:Carcinoma, Papillary / Q000378:metabolism* / Q000473:pathology; D005260:Female; D006044:Goiter, Nodular / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D016130:Immunophenotyping / Q000379:methods; D053555:Keratin-5 / Q000378:metabolism*; D053553:Keratin-6 / Q000378:metabolism*; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism*; D008875:Middle Aged; D013961:Thyroid Gland / Q000378:metabolism / Q000473:pathology*; D013964:Thyroid Neoplasms / Q000378:metabolism* / Q000473:pathology; D013967:Thyroiditis, Autoimmune / Q000378:metabolism / Q000473:pathology
chemical_list: C081876:CKAP4 protein, human; D053555:Keratin-5; D053553:Keratin-6; D008565:Membrane Proteins
keywords: CK5/6; Cytokeratin; Lymphoepithelial complex; P63; Squamous cell metaplasia; Thyroid; Thyroiditis