PMC8714348_01
Screening chest CT scan that originally identified the 19 x 22 mm nodule in the left upper lobe of the lung (red circle). Left hilar adenopathy was also noted on presentation (yellow circle). Intralobular septal thickening was also noted.
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At that time, age-appropriate cancer screening was initiated, including a low-dose CT (computed tomography) scan of the thorax, which identified a 19 x 21 mm nodule, left hilar lymphadenopathy, and intralobular septal thickening in the left upper lobe (Figure 1) suspicious for pulmonary venous obstruction.
CT thorax with contrast sagittal (a) and coronal (b) representative views of the patient's mass measuring 3.3 x 2.4 cm. A sequence depicting the origination of the mass as it invades the left superior pulmonary vein before its extension in the left atrium (c).
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Thorax with contrast verified a mass in the aortopulmonary window measuring 3.3 x 2.4 cm (Figures 2(a) and 2(b)) and extending proximally into the left superior pulmonary veins and subsequently the left atrium (Figure 2(c)).
Transthoracic echocardiography (TTE) image of a mobile ecodensity measuring 3.0 cm x 1.6 cm. Doppler radar of the flow (not shown here) did not show obstruction of flow, which contributed to the patient's asymptomatic status.
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Transthoracic echocardiography (TTE) revealed a left ventricular ejection fraction (LVEF) of 61% with a 3.0 cm x 1.6 cm mobile echo density with a poorly defined variegated surface visualized in the left atrium attached to the roof of the atrium (Figure 3).
Histological sections of the left hilar mass. (a) Sections show cores of lung parenchyma replaced by a malignant neoplasm with significant pleomorphism, nuclear vacuoles, and abundant necrosis. Immunostaining showed positivity for (b) cytokeratin AE1/AE3, (c) CAM5.2, (d) p63, (e) CD5 (patchy), and (f) CD117 (patchy). The tumor cells are negative for PAX-8, napsin, TTF-1, CK7, CK20, S100, TTF-1, synaptophysin, chromogranin, and CDX-2 (not shown). This immunoprofile is supportive of a thymic origin and was diagnosed as poorly differentiated squamous cell carcinoma. There were not enough tissues to perform ancillary molecular studies.
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The tumor cells had an immune profile that was supportive of thymic origins with positive staining for cytokeratin ae1/ae3, CAM5.2, p63, CD5 (patchy), CD117 (focal and patchy), and negative staining for PAX-8, napsin, TTF-1, CK7, CK20, S100, synaptophysin, chromogranin, and CDX-2 (Figure 4).