title: Hyalinizing trabecular adenoma--a case report with FNAC histologic, MIB-1 proliferative index and immunohistochemical findings.
abstract: Hyalinizing trabecular adenoma is a recently described benign thyroid tumor, almost exclusively occurring in females. The morphological features of this entity overlap with both papillary and medullary carcinoma to varying extent. This, in turn, creates a situation of serious diagnostic pitfall particularly for a false positive diagnosis of papillary carcinoma in fine needle aspiration (FNA) cytology. False consideration of medullary carcinoma is also possible by the unwary especially if staining for Congo red and/or immunostaining for calcitonin is not resorted to. At histologic level, the distinctive architectural pattern is however of great help and thus poses a much lesser danger of misdiagnosis. We relate here our experience in a recently encountered case of hyalinizing trabecular adenoma and describe detailed FNA cytologic and histologic findings along with immunohistochemical profile using a panel of eight monoclonal antibodies. The tumor proliferative potential has also been assessed using MIB-1 (Ki-67) immunostaining. The various pros and cons of diagnostic pitfalls are discussed.
authors.affiliation: Department of Pathology, All India Institute of Medical Sciences, INMAS, New Delhi.
authors.forename: A K
authors.initials: AK
authors.lastname: Karak
authors.forename: M
authors.initials: M
authors.lastname: Sahoo
authors.forename: D
authors.initials: D
authors.lastname: Bhatnagar
mesh_terms: D000236:Adenoma / Q000473:pathology*; D000328:Adult; D001707:Biopsy, Needle; D018276:Carcinoma, Medullary / Q000473:pathology; D002291:Carcinoma, Papillary / Q000473:pathology; D002455:Cell Division; D005260:Female; D006801:Humans; D006818:Hyalin; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000032:analysis; D008872:Microwaves; D013961:Thyroid Gland / Q000737:chemistry / Q000473:pathology; D013964:Thyroid Neoplasms / Q000473:pathology*
chemical_list: D019394:Ki-67 Antigen