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thyroid Bethesda category 4
Friday 19 August 2016
Thyroid Bethesda class IV
Images
Predominantly microfollicular smear in thyroid FNA w no colloid. Bethesda Category IV. Class 4.
The aim of Bethesda category 4 is to identify a nodule that might be a follicular carcinoma. Follicular carcinomas have cytomorphologic features that distinguish them from benign follicular nodules but do not permit distinction from a follicular adenoma (FA).
They are reportable as FN or SFN. About 15–30% of these cases called FN/SFN prove to be malignant, the rest being FAs or adenomatoid nodules of MNG.
The criteria for reporting under TBSRTC category IV are :*
significant alteration in the follicular cell architecture, characterized by cell crowding, micro follicles, dispersed isolated cells and scant or absent colloid.
The criteria for FN Hurthle cell type/suspicious for a FN Hurthle cell type FNHCT/SFNHC (subcategory of TBSRTC IV) are a sample consisting exclusively of hurthle cells, usually little or no colloid or virtually no lymphocytes or plasma cells
TBSRTC recommends lobectomy for this category.
See also
thyroid FNA
Open references
The Bethesda System for Reporting Thyroid Cytopathology: Interpretation and Guidelines in Surgical Treatment. Renuka IV et al., 2012. (Open access) http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3477437/