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case_images: Radiological findings. (A) T1-weighted brain magnetic resonance image showing low mixed signal intensity (arrow). (B) T2-weighted image showing an isointense-to-hypointense lesion (arrow). (C) Chest computed tomography scan showing a 52mm mass with necrosis on the manubrium of the sternum (arrow).
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case_images: These particular MRI features are consistent with those of cavernous angioma with hemorrhage (Fig. 1A and 1B). A chest computed tomography (CT) scan was performed to assess the mass in the sternum and revealed a huge infiltrating tumor mass with necrosis extending into the manubrium (Fig. 1C).
case_images: Microscopic findings of the brain and sternum tumor masses. (A) Low-power view of the resected right frontal mass showing a cystic and solid mass with hemorrhage (H&E, x10). (B) Low-power view of the brain mass revealing the branching and complex papillary structure of the tumor cells (H&E, x400). (C) High-power view of the brain mass showing the columnar atypical tumor cells with increased nuclear stratification. The eosinophilic colloid-like material within the lumen is also noted (arrowhead; H&E, x100). (D) High-power view of the biopsied sternum mass showing the presence of histological features that were identical to the brain mass, i.e., complex papillary fronds and the same cytological findings. There are also increased mitotic figures (arrows; H&E, x400). Immunohistochemistry (IHC) for (E) cytokeratin 7, (F) thyroid transcription factor-1 (TTF-1), (G) napsin A, and (H) thyroglobulin. Unlike the classic IHC findings for metastatic adenocarcinomas from the lung (i.e., positivity for all three tissue-specific gene expression), the sternum mass expressed only cytokeratin 7 (E) and TTF-1 (F) but not napsin A (G, x200). The IHC analysis also revealed that the sternum mass expressed thyroglobulin (H, x200), which is consistent with a diagnosis of metastatic thyroid cancer.
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case_images: A histological analysis of the brain mass under a low-power view revealed a cystic and solid tumor mass that was infiltrating into the brain parenchyma with hemorrhage (Fig. 2A and 2B) and a histological analysis under a high-power view revealed predominant branching papillary structures in the tumor that were composed of columnar cells with increased nuclear stratification (Fig. 2C). The sternum mass had identical histological features, i.e., the presence of complex papillary structures and equivalent cytological findings (Fig. 2D). The mass was positive for cytokeratin 7 and TTF-1 but negative for napsin A (Fig. 2E-2G). TTF-1 expression, the sternum mass was assessed for thyroglobulin expression and the IHC analysis revealed a strong expression of thyroglobulin (Fig. 2H). The final pathological diagnosis was metastatic columnar cell-variant PTC, which is a very rare variant.
case_images: Findings from the thyroid ultrasonography, fine-needle aspiration, and positron emission tomography-computed tomography (PET-CT) scans. (A) Ultrasonography scan showing the presence of a 5 x 5 x 10 mm hypoechoic nodule with coarse calcification at the thyroid isthmus. (B) Fine-needle aspiration cytology of the thyroid gland showing the presence of angulated tumor cell nests with intranuclear grooves and prominent intranuclear pseudoinclusion (arrow; Pap smear, x400). (C) PET-CT scan revealing a low density and mildly hypermetabolic nodule in the right lobe of the thyroid gland. (D) PET-CT scan revealing a large infiltrating intensely hypermetabolic mass in the manubrium and upper sternal body.
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case_images: A single hypoechoic nodule (5 x 5 x 10 mm sized) with coarse calcification in the isthmus (Fig. 3A) and two indistinct subtle hyperechoic masses (8 x 8 x 11 mm and 4 x 5 x 5 mm) were detected in the right thyroid. All lymph nodes appeared normal and fine-needle aspiration of the isthmic thyroid nodule confirmed the diagnosis of PTC (Fig. 3B). To determine whether there were additional metastatic lesions, a positron emission tomography-CT scan was performed and revealed a low density and mildly hypermetabolic nodule in the right lobe of the thyroid gland (Fig. 3C) as well as a large infiltrating intensely hypermetabolic mass in the manubrium and upper sternum body (Fig. 3D).
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