PMC6161500_01
(a) Diff-Quik stained smears showing clusters of epithelioid cells with hyperchromatic nuclei. (b) Diff-Quik stained smears showing similar-appearing singly dispersed epithelioid cells with hyperchromatic and irregular nuclei
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F1
The Diff-Quik-stained smears showed singly dispersed and clusters of epithelioid cells with dark chromatin and abundant cytoplasm [Figure 1a and b].
Papanicolaou-stained smears showing atypical epithelioid cells with abundant dense cytoplasm and orangeophilia
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F2
A Papanicolaou-stained smear showed epithelioid cells with dense and focally orangeophilic cytoplasm [Figure 2].
Cell block showing cohesive cells with squamous features and atypical nuclei
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F3
A cell block showed brightly eosinophilic cells with squamoid features [Figure 3].
(a) Cell block showing tumor cells with positive immunostaining for p63. (b) Cell block showing tumor cells with positive immunostaining for cytokeratin 5/6. (c) Cell block showing tumor cells with negative immunostaining for thyroid transcription factor-1. (d) Cell block showing tumor cells with negative immunostaining for thyroglobuin
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F4
Immunohistochemical stains were performed and showed the cells were immunoreactive for p63 and cytokeratin 5/6 and negative for thyroid transcription factor-1 (TTF-1) and thyroglobulin [Figure 4a-d].
(a) Low power H and E of resection specimen showing a tumor with papillary architecture in a dense fibrous stroma. (b) High-power H and E of resection specimen highlighting papillary architecture with fibrovascular cores. (c) H and E of resection specimen showing papillary tumor with enlarged overlapping nuclei and cleared chromatin. (d) High power H and E of resection specimen highlighting nuclear features of papillary thyroid carcinoma including overlapping nuclei, cleared chromatin, and focal nuclear grooves. (e) High power H and E of resection specimen showing nuclear and histologic features of classic variant of papillary thyroid carcinoma
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F5
The PTC areas of the tumor showed papillary structures with fibrovascular cores [Figure 5a-e] and cells with nuclear enlargement, overlapping, grooves, and pale chromatin.
(a) Low power H and E of resection specimen showing component of tumor with squamous features including infiltrating tumor cells in sheets with keratin pearls. (b) High power H and E of resection specimen showing tumor with squamous features including sheet-like architecture, abundant eosinophilic cytoplasm, keratin pearls, and dyskeratotic cells
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F6
The SCCa areas showed islands and nests of eosinophilic cells with squamous differentiation and focal keratinization [Figure 6a and b].
(a) Papillary thyroid carcinoma component with negative immunostaining for p63. (b) Papillary thyroid carcinoma component with negative immunostaining for cytokeratin 5/6. (c) Papillary thyroid carcinoma component with positive immunostaining for thyroid transcription factor-1. (d) Papillary thyroid carcinoma component with positive immunostaining for thyroglobulin
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F7
TTF-1 and thyroglobulin [Figure 7a-d].
(a) Squamous cell carcinoma component with positive immunostaining for p63. (b) Squamous cell carcinoma component with positive immunostaining for cytokeratin 5/6. (c) Squamous cell carcinoma component with negative immunostaining for thyroid transcription factor-1. (d) Squamous cell carcinoma component with negative immunostaining for thyroglobulin
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F8
The SCCa component stained the exact opposite; immunoreactive for p63 and cytokeratin 5/6 and negative for TTF-1 and thyroglobulin [Figure 8a-d]. The tumor was found to be positive for BRAF V600E by immunohistochemical analysis (clone VE1, Ventana) in the SCCa component.