Histologic changes: In some areas the tumor showed another aspect of squamous differentiation. What it it? Answer

Clinical summary Image 4

Table of Contents

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Answer: Several of the tumor nests show central, rounded foci of spindled keratinized cells (arrow). These are referred to as keratin pearls. The pearl at the bottom shows an inflammatory infiltrate and necrosis. Note again that the cells at the edge of the nests have scant cytoplasm. Squamous differentiation occurs toward the center: increased cytoplasm, bridges, and, finally, pearls develop.

Note: A tumor must have either bridges or pearls to qualify as showing squamous differentiation.

Staging: After resection, histologic TNM staging was pT2N1MX, Stage IIB.

Comment: This small cell carcinoma showed foci of both squamous and glandular differentiation. About 90% of the lung tumor and all of the lymph node metastases were small cell type. Immunohistochemical stains for chromogranin A and synaptophysin were negative. By electron microscopy, a few small neurosecretory granules were seen in otherwise undifferentiated cells. The tumor invaded the overlying visceral pleura, but that feature does not change the T number of a 4-cm tumor.

Clinical summary Image 4

Top

Table of Contents