Papillary Thyroid Carcinoma, Variants, and Related Tumors

Background The definition of tall cell variant of papillary thyroid carcinoma (TCV‐PTC) depends on the articles, and the defined cytological findings characteristic of TCV‐PTC have not yet been fully analyzed. This study aimed to establish the cytological characteristics of TCV‐PTC. Methods We retrospectively analyzed the smears of 19 TCV‐PTC and 50 conventional PTC (C‐PTC) cases. Results Palisaded pattern with the nuclei locating at the base of tall columnar carcinoma cells was seen in 94.7% of TCV‐PTCs, and the incidence was significantly higher than that of C‐PTCs ( P < .0001). The palisaded pattern tended to appear at the periphery of the cell clusters. Isolated tall columnar carcinoma cells were present in 89.5% of TCV‐PTCs. The incidence was significantly higher than that of C‐PTC ( P = .0001). Tombstone appearance was identified in 78.9% of TCV‐PTCs, but not in C‐PTCs. Spindle‐like carcinoma cells with tapering cytoplasmic end appeared in 68.4% and 12.0% of TCV‐PTC and C‐PTC, respectively ( P < .0001). The cytoplasm of TCV‐PTC was densely stained and its cell border was distinct. Cytoplasmic elongation toward an outside of the cell clusters was observed in 89.5% of TCV‐PTCs. Conclusion It is the most important to identify the presence of the tall columnar carcinoma cells on the cytological preparations, in order to distinguish TCV‐PTC from C‐PTC. We propose five cytological findings indicating TCV‐PTC, (1) palisaded pattern, (2) tall columnar cells with the heights of at least three times their widths, (3) tombstone appearance, (4) spindle‐like carcinoma cells, and (5) cytoplasmic elongation.

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Diagnostic clues indicating tall cell variants of papillary thyroid carcinoma in fine needle aspiration

Tanaka

Hirokawa

Higuchi

et al. 2018

“…It is frequently associated with familial adenomatous polyposis (FAP), otherwise known as Gardner syndrome, but sporadic forms are also seen. 4 The immunohistochemical phenotype is positive for thyroid transcription factor (TTF-1) with focal staining for thyroglobulin, cytokeratin 7 (CK7), and CK19. In sporadic cases, it occurs as a solitary nodule.…”

Section: Introductionmentioning

confidence: 99%

Pulmonary metastasis of cribriform‐morular variant of thyroid carcinoma mimicking primary adenocarcinoma of the lung: A potential pitfall

Laforga¹,

Pedro²,

Gasent³

2019

Cribriform-morular variant of papillary thyroid carcinoma (CMV-TC) shows a peculiar mixture of follicular, cribriform, papillary, trabecular, and solid patterns with squamoid morules. Ocassionally, lung metastasis may be interpreted incorrectly as primary lung adenocarcinoma. We illustrate a case of pulmonary meastasis of CMV-TC mimicking a primary adenocarcinoma, 7 years after diagnosis of CMV-TC. The lung metastases may be easily missed if the pathologist is unaware of the patient's prior history and a limited immunohistochemical panel (CK7 and TTF-1) is used. The histologic and immunohistochemical (β-catenin+, ER+, PR+, TTF-1 +, and CK7+) findings were diagnostic of CMV-TC and ensured adequate treatment. K E Y W O R D Scribriform-morular variant of papillary thyroid carcinoma, cytology, diagnosis, immunohistochemistry, lung metastasis

“Teardrop,” “comet,” and “bowling‐pin” cells in a hobnail variant of papillary thyroid carcinoma fine needle aspirate

Mehrotra

Lapadat

Barkan

et al. 2019

Diagnostic Cytopathology. 2019;47:839-842.wileyonlinelibrary.com/journal/dc dows"), all reminiscent of mesothelial cells. Some of the peripheral cytoplasmic blebs were larger, appeared to separate from the cell bodies by thin pale lines, and resembled the apical cap ("snout") of apocrine cells; similar-sized cytoplasmic fragments were seen in the background. Mitotic figures were easily identified. The smear background showed scant colloid, numerous red blood cells, granular debris and occasional plasma cells, neutrophils, eosinophils, and lymphocytes. Based on these cytologic findings, a diagnosis of papillary thyroid carcinoma (PTC) with hobnail features was rendered. The ensuing total thyroidectomy and lymph node dissection showed a 5.3 cm PTC involving the entire thyroid, without extrathyroid extension, metastatic to six cervical and mediastinal lymph nodes. Most of the tumor had features of the hobnail variant of PTC (HVPTC; Figure 5A-D); minor components (less than 10% each) of classical, follicular, and tall cell variant were also present, as was a small area showing rhabdoid morphology. The hobnail variant of PTC (HVPTC) was described in 2010 1 as a rare aggressive variant of PTC and is included in the current WHO classification of thyroid tumors 2 and the updated Bethesda system for reporting thyroid cytopathology 3 . This variant, which constitutes 0.2% to 1.7% of PTC, is defined as nonsolid PTC with more than 30% of neoplastic cells with hobnail features and less than 10% tall cell, columnar cell or diffuse sclerosing features. 4 It has a papillary architecture, with papillae lined by crowded pseudostratified cuboidal to columnar cells with eosinophilic cytoplasm that have lost their polarity; their normally basally located nuclei are pushed to the middle of the cell or to the apical pole, appearing to be bulging out. Concomitantly, there is loss of cohesion and formation of micropapillary structures devoid of fibrovascular cores. The HVPTC is associated with older age, female sex, larger tumors, more frequent multifocality, extrathyroidal extension, vascular invasion, lymph node, and distant metastases, presence of foci of necrosis and of anaplastic carcinoma, 5 and poor prognosis. It shows positivity for cytokeratins (CK AE1/3, CK 7, CK 19), EMA, thyroglobulin, PAX8, TTF1, HBME-1, and increased p53 (25%) and Ki67 (5%-10%) staining and frequently harbors BRAFV600E mutations (rarely coexisting with TERT mutations), p53 mutations and occasionally RET/PTC1 rearrangements. 6,7 FNA cytologic features of HVPTC 8-12 include hypercellularity with cells arranged in papillary/micropapillary clusters with a variable proportion of single cells; the cells are elongated, have well-defined cell borders, apically placed "bulging" nuclei and cytoplasmic tails, imparting them a "comet" or "teardrop" appearance. The nuclei are enlarged, moderately to markedly pleomorphic and hyperchromatic and may show prominent nucleoli; nuclear grooves and intranuclear inclusions are rare. Despite these nuclear features which are unusu...