Pembrolizumab - emerging treatment of pulmonary sarcomatoid carcinoma: A case report

Figure 1 Chest computed tomography. A, B: Prior to initiation of pembrolizumab, with yellow arrows pointing to a left upper lobe primary measuring 14.1 cm × 10.6 cm × 14.9 cm. C, D: After 5 cycles of pembrolizumab, with yellow arrows pointing to a markedly decreased left upper lobe mass measuring 8.0 cm × 7.7 cm × 6.8 cm.

Figure 2 Histological lung section. A: Hematoxylin and eosin staining showing sarcomatoid carcinoma, with visible spindle cells and rare epithelioid cells (magnification, 100 ×); B: Immunohistochemical staining showing sarcomatoid carcinoma with neoplastic cells positive for CK7 (magnification, 200 ×); C: Hematoxylin and eosin staining showing sarcomatoid carcinoma, with cells positive for programmed death-ligand-1 and tumor proportion score greater than 50% (magnification, 400×).

Figure 3 Chest positron emission tomography - computed tomography (lung window) after 9 cycles of pembrolizumab, with the yellow arrow pointing to an fluorodeoxyglucose-avid 5. 5 cm × 4 cm mass in the left upper lobe, with central necrosis and a maximum standardized uptake value of 8.6, consistent with malignancy. Inferiorly and in its continuation, there is a second lesion measuring 2.3 cm × 1.8 cm with a maximum standardized uptake value of 7.2, interpreted as a remnant from the initial tumor.