PMC5723948_01
Findings from ultrasonography and computed tomography. The right thyroid lobe and thyroid isthmus are present, while the left lobe of the thyroid is absent. A nodule measuring 0.7 x 0.8 x 1.4 cm is seen on the left side of the thyroid isthmus. On cervical ultrasonography, the periphery of the tumor is nonuniform, small calcifications are detected in the interior, and the posterior echo is attenuated. Arrows indicate the tumor. No cervical lymph node swelling is detected.
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A 0.7 x 0.8 x 1.4 cm hypoechoic nodule with small calcifications and attenuation of posterior echo and a 0.8 x 0.7 cm enhanced nodule with clear borders were identified on the left side of the isthmus (Figure 1).
Surgical findings. The left lobe of the thyroid is absent. Tumor is observed on the side of the absent thyroid and has invaded the lateral branch of the recurrent laryngeal nerve. No abnormalities in the path of the recurrent laryngeal nerve are observed. Arrowheads indicate tumor; arrow indicates craniad.
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The tumor had invaded the lateral branch of the recurrent laryngeal nerve, which was also resected, but the medial branch of the recurrent nerve was preserved (Figure 2).
Tumor histopathology. Although the right thyroid lobe and isthmus were evident, left lobe tissue was absent. Most of the tumor represented papillary carcinoma, with a minority portion comprising poorly differentiated carcinoma. No thyroid tissue was observed in the absent portion. Arrow indicates right side. Hematoxylin and eosin staining, x1.
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fig3
The tumor was adjacent to the left side of the isthmus (Figure 3), and a clear demarcation was evident between the thyroid and tumor (Figure 4).
Histopathology of Section A in Figure 3. Clear demarcation is evident between the thyroid tissue and tumor. Dotted line delineates normal thyroid tissue truncating at the isthmus. Arrowheads point to the tumor site. Hematoxylin and eosin staining, x1.25.
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fig4
The tumor was adjacent to the left side of the isthmus (Figure 3), and a clear demarcation was evident between the thyroid and tumor (Figure 4).
Histopathological (hematoxylin and eosin) and immunohistochemical findings for Sections B and C in Figure 3. Images (a), (c), and (d) are from Section B (thyroid papillary carcinoma), while images (b) and (d) are from Section C (poorly differentiated carcinoma) in Figure 3. (a) The tumor shows a ductal structure with funicular and microfollicular shapes, consistent with thyroid papillary carcinoma. (b) A honeycomb structure and necrosis are observed, with marked differences in nucleus sizes; these findings suggest poorly differentiated carcinoma. (c, d) Both papillary carcinoma and poorly differentiated carcinoma sites are thyroid transcription factor-1-positive. (e) Nuclear grooves under high magnification.
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Most of the tumor was consistent with thyroid papillary carcinoma with a funicular- and microfollicular-shaped ductal structure, and nuclear grooves were observed within the tumor cells at high magnification (Figures 5 and 5). A honeycomb structure and necrosis were observed in a section of the infiltrating tumor, and a marked difference was seen in the sizes of nuclei, indicative of poorly differentiated thyroid carcinoma (Figure 5). In addition, immunohistochemical staining showed that both the papillary and poorly differentiated carcinomas were thyroid transcription factor- (TTF-) 1-positive, suggesting that the carcinomas originated from thyroid tissue (Figures 5 and 5).