Nameera Saleem1, Naval Kishore Bajaj2, Ezhil Arasi Nagamuthu3
BACKGROUND
Papillary thyroid carcinoma is the most common malignancy of the thyroid gland.
Fine Needle Aspiration Cytology (FNAC) is a rapid, safe and economic procedure,
and has a sensitivity approaching of 93.5 % and specificity close to 90 % for
diagnosing papillary thyroid carcinomas. This study aims at correlating the
cytological and histological diagnosis to arrive at the rate of concordance and
discordance, identify variants of papillary thyroid carcinoma (PTC) on cytology and
discuss the cytological mimics of PTC.
METHODS
Data from cases was collected over a period of three years (2015 - 2018). A
descriptive study was done. Cases from Osmania General Hospital representing
histologically proven cases of papillary carcinoma thyroid along with their
corresponding cytological findings were analysed. Cytosmears were obtained from
fine needle aspiration of thyroid lesions using a 26-gauge needle, stained with
haematoxylin and eosin (H&E). Thyroidectomy specimens were fixed in 10 %
buffered formalin, grossed and paraffin embedded. After processing, sections
obtained by microtomy were stained with H & E for histopathologic evaluation.
RESULTS
The institute received a total of 258 thyroid specimens for histopathology and 686
cases for thyroid FNAC over a period of three years. This study includes 70 cases
which had both cytology and histopathology correlation at our institution. 65 cases
were diagnosed as PTC on histopathology and correct diagnosis was made on
cytology with 73.8 % concordance (48 / 65 cases) and discordance was seen in
26.1 % (17 / 65 cases). 5 cases were misdiagnosed on cytology as PTC, and on
histopathological examination were diagnosed as non-PTC.
CONCLUSIONS
Fine needle aspiration shows variable accuracy for PTC, ranging from 65 % to 90
%. The architectural arrangement of cells in papillary fragments and presence of
nuclear features in majority of cells is diagnostic of the conventional variant of
PTC. The other variants however, pose a diagnostic dilemma on account of their
architectural variation, altered cytomorphology and the scant presence of nuclear
features. An increase in the awareness of cytomorphology of variants and also of
the mimics of PTC helps improve the diagnostic accuracy on FNAC.
