PMC6928194_01
(A) CT scan section of thyroid neoplasia. (B) CT scan section of lung neoplasia. (C) Undifferentiated carcinoma with marked nuclear atypia intermixed to thyroid follicles in thyroid Tru-cut. Magnifications: x200. (D) Adenocarcinoma with mucinous differentiation in bronchial biopsy. Magnifications: x200. (E-G) Immunohistochemistry in thyroid Tru-cut showing focal immunoreactivity for TTF-1 and absence of immunoreactivity for Thyroglobulin and PAX-8 markers. Original magnifications: x200. (H-J) Immunohistochemistry in bronchial biopsy showing absence of immunoreactivity for TTF-1, Thyroglobulin, and PAX-8 markers. Original magnifications: x200. (K,L) Mass spectrometry of thyroid neoplasia with substitution c.34G>T (p.G12C) in the codon 12 of kRAS gene. (M,N) Mass spectrometry of lung neoplasia with substitution c.34G>T (p.G12C) in the codon 12 of kRAS gene.
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F1
To assess the neoplastic status of the patient, we performed a total body CT scan with i.v. contrast medium that showed the presence of multiple metastatic lymph nodes (max diam 17 mm in the right latero-cervical region) and a large thyroid gland with increased dimension in particular in the right lobe (Figure 1A). Moreover, the CT scan showed a large mass (9.0 x 4.5 cm) in the mediastinum, linked to the thyroid mass, involving the left upper lung lobe and occluding the left pulmonary artery branch (Figure 1B). Tru-Cut biopsy showed a poorly differentiated thyroid carcinoma (PDTC) with several anaplastic areas (Figure 1C). TTF-1 focally positive, Tg, and PAX-8 negative (Figures 1E-G). The bronchus brushing showed the presence of an adenocarcinoma with widespread mucinous aspects, confirmed by biopsy (Figure 1D). The immunohistochemistry was CK7 positive, TTF-1, Napsin A, Tg, and PAX-8 negative (Figures 1H-J). Both, thyroid (Figures 1K,L) and lung (Figures 1M,N) samples showed the substitution c.34G>T (p.G12C) in the codon 12 of K-RAS gene, while all the other mutations analyzed were negative.