Asymptomatic Tumor Thrombus in the Left Atrium from Squamous Cell Carcinoma

Figure 4

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.