title: Morphological changes of follicular cell basal borders and basement membranes in benign and malignant nodular lesions of the thyroid gland: an ultrastructural study.
abstract: Microfollicular nodular lesions of the thyroid gland may represent a differential diagnosis problem. Firstly, nodular areas of follicular hyperplasia have to be distinguished from follicular adenomas. On the other hand, nodular microfollicular areas exhibiting large pale nuclei, occasionally found in hyperplastic nodules and follicular adenomas, must be discriminated from latent papillary carcinomas with predominant follicular architecture. The diagnosis of follicular carcinoma still requires the detection of vascular and/or capsular microinvasion. A more refined study was planned to search for additional descriptors useful for diagnosis The authors report the results of an ultrastructural investigation carried out on 220 thyroid nodular lesions and 50 specimens of macroscopically nonnodular glands. An infolding arrangements of the thyreocyte basal border (TBB) and follicular basement membrane (FBM) was demonstrated in 50/50 nonnodular thyroid tissue specimens and 53/67 (79.1%) hyperplastic nodular lesions (p<.005). A linear arrangement of the TBB and FBM was found in 85/121 (70.2%) follicular adenomas and in 32/32 differentiated carcinomas (p<.001). In the last group, 12/32 (37.5%) cases showed focal discontinuities of FBM. In conclusion, the benign thyroid nodules show a prevalently infolding arrangements of TBBs, whereas the majority of proliferative lesions display a linear morphology. In absence of an infiltrating pattern there is no morphological evidence of discriminating potentially malignant vs. benign lesions. The linear distribution of TBBs and FBMs places the case in a group of borderline lesions that involve a more careful postsurgery investigation.
authors.affiliation: Unit of Ultrastructural Pathology, Department of Human Pathology, University of Messina, Messina, Italy. vcavallari@unime.it
authors.forename: Vittorio
authors.initials: V
authors.lastname: Cavallari
authors.forename: Francesca
authors.initials: F
authors.lastname: Albiero
authors.forename: Rocco
authors.initials: R
authors.lastname: Cicciarello
authors.forename: Maria Ester
authors.initials: ME
authors.lastname: Gagliardi
authors.forename: Gregorio
authors.initials: G
authors.lastname: Costa
authors.forename: Claudio
authors.initials: C
authors.lastname: D'Alia
authors.forename: Giovanni
authors.initials: G
authors.lastname: Sturniolo
authors.forename: Ada
authors.initials: A
authors.lastname: Tonante
authors.forename: Agata
authors.initials: A
authors.lastname: Labate
authors.forename: Valerio
authors.initials: V
authors.lastname: Torre
authors.forename: Francesco
authors.initials: F
authors.lastname: Vermiglio
authors.forename: Bernard
authors.initials: B
authors.lastname: Caillou
mesh_terms: D000236:Adenoma / Q000473:pathology / Q000648:ultrastructure; D000328:Adult; D000368:Aged; D001485:Basement Membrane / Q000473:pathology* / Q000648:ultrastructure*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D006965:Hyperplasia / Q000473:pathology; D008297:Male; D046529:Microscopy, Electron, Transmission; D008875:Middle Aged; D016606:Thyroid Nodule / Q000473:pathology* / Q000648:ultrastructure*