PMC7105337_01
(A) Struma and PTC x40. (B) PTC x40. (C) PTC x400. PTC (arrow) can be seen arising in the background of benign thyroid tissue (1A) (Hematoxylin and Eosin, x40). The carcinoma exhibits the classical papillary architecture (1B) as well as diagnostic cytologic features (Hematoxylin and Eosin, x40). The latter includes cuboidal-to-low columnar cells with overlapping nuclei, nuclear grooves (arrows), and the presence of optically clear chromatin (arrowheads) (1C) (Hematoxylin and Eosin, x400).
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Occasional nuclei showed optically clear cytoplasm, while others had nuclear grooves (Figure 1).
Struma x100. Also present are foci of relatively more recognizable thyroid tissue, consistent with a struma ovarii. The colloid-filled acini are lined by a single layer of flat-to-low cuboidal cells just like in the eutopic thyroid. (Hematoxylin and Eosin, x100).
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Of note, the struma ovarii made up the bulk of the tumour and consisted of colloid-filled acini lined by a single layer of flat-to-low cuboidal cells like those seen in normal thyroid tissue (Figure 2).
(A): Struma and hair follicles x100. The mature teratoma shows intimate admixture with thyroid tissue, the greatest component of the tumor in this case. Hair follicles (arrows) can be seen amongst small acini filled with colloid (microfollicular pattern) (arrowhead) (Hematoxylin and Eosin, x100). (B): Bone and hair follicles x200. (C): Epidermoid x200. (D) Cartilage x100. Mature teratoma component. The tumor shows foci consistent with a mature teratoma showing derivation from at least two of the three germ layers (ectoderm, mesoderm, and endoderm). The various mature elements include hair follicles (arrows) intermixed with bone (arrowhead) (3A), squamous epithelium (3C), and cartilage (arrow) juxtaposed with adipose tissue (arrowhead) (3D) [Hematoxylin and Eosin, x200 (1A, 1B), x100 (1C)].
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However, other teratomatous elements were also identified, including mature bone, cartilage, adipose tissue, squamous epithelium and hair follicles (Figure 3).
(A): Carcinoid x100. (B): Carcinoid x400. (C): Synaptophysin x400. (D): Chromogranin x400. An incidental focus of insular carcinoid (0.3 cm) was identified in one of the tumor sections. The carcinoid tumor consists of solid nests made up of uniform cells with centrally-placed nuclei (4A) (Hematoxylin and Eosin, x100) and (4B) (Hematoxylin and Eosin, x400). The tumor is positive for the neuroendocrine immunohistochemical markers synaptophysin (4C) and chromogranin A (4D) (x400), while negative for CK7 (not shown). The Ki-67 proliferation index of the tumor is less than 1%, and no mitotic figures were identified (not shown).
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