Constitutive Cytomorphologic Features of Medullary Thyroid Carcinoma Using Different Staining Methods

Abstract

(1) Background: Accurate preoperative identification of medullary thyroid carcinoma (MTC) is challenging due to a spectrum of cytomorphologic features. However, there is a scarcity of studies describing the cytomorphologic features as seen on fine-needle aspiration (FNA) smears prepared using different staining methods. (2) Methods: We performed a retrospective study on MTC cases with available FNA slides from 13 hospitals distributed across 8 Asia-Pacific countries. The differences in the constitutive cytomorphologic features of MTC with each cytopreparatory method were recorded. A comparative analysis of cytologic characteristics was carried out with appropriate statistical tests. (3) Results: Of a total of 167 MTC samples retrospectively recruited, 148 (88.6%) were interpreted as MTC/suspicious for MTC (S-MTC). The staining methods used were Papanicolaou, hematoxylin-eosin, and Romanowsky stains. Seven out of the eleven cytologic criteria can be readily recognized by all three cytopreparatory methods: high cellularity, cellular pleomorphism, plasmacytoid cells, round cells, dyshesive cells, salt-and-pepper chromatin, and binucleation or multinucleation. An accurate diagnosis was achieved in 125 (84.5%) of the 148 samples whose FNAs exhibited five or more atypical features. Conclusions: The present work is the first study on MTC to compare the morphological differences among the cytologic staining techniques. We investigated the constitutive features and the reliability of diagnostic parameters. A feasible scoring system based upon cytomorphologic data alone is proposed to achieve a high degree of diagnostic accuracy.

Papillary and medullary thyroid carcinomas coexisting in the same lobe, first suspected based on fine-needle aspiration cytology: a case report

“…Because diagnosing MTC based on cytomorphology alone is very challenging due to its rarity compared with PTC and the wide spectrum of cytologic features that often overlap with other neoplasms, the detection rate of FNAC in patients with MTC ranged from 12.5%–88.2% in a meta-analysis including 15 relevant studies and 641 MTC patients who underwent FNAC [ 24 ]. Seven cytomorphologic features were readily recognized in FNAC of MTC: high cellularity, cellular pleomorphism, plasmacytoid cells, round cells, discohesive cells, salt-and-pepper chromatin, and binucleation or multinucleation [ 25 ]. In another study, the following important cytologic parameters for MTC were also suggested: a dispersed cell pattern of polygonal cells, azurophilic cytoplasmic granules, and eccentric nuclei with coarse granular chromatin and amyloid [ 26 ].…”

Follicular Growth Pattern Disease on Thyroid Fine-needle Aspiration Biopsy

“…55 Microfollicles show a uniform appearance; other features of these lesions include trabeculae, crowded cell groups, and isolated single cells in the background. 56 , 57 Cases with scanty colloids with a macro/microfollicular pattern are not covered by this term even if the smear is hypercellular. These lesions should be considered benign nodules or AUS/FLUS depending on the amount of colloid, microfollicle ratio, and cellularity.…”

Cytomorphological analysis of histologically confirmed cases of medullary thyroid carcinoma

“…Problematikus esetekben az immuncitokémia, szérum kalcitonin szint meghatározás és az FNA washout fluid kalcitonin szint elemzése, segíthet az MTC diagnózisában [25,26]. A kalcitonin szint jelentősége A vérben emelkedett kalcitonin szint és pajzsmirigy göb együttes jelenléte az MTC alapos gyanúját veti föl, de az MTC diagnosztikájában elsővonalbeli diagnosztikai módszer az FNAC, mely megbízhatóságát a kalcitonin immuncitokémiai kimutatásával jelentősen növelni lehet.…”