Find two areas of central necrosis in the nests of tumor cells.
Histologic Changes
Figure 1. The tumor showed one predominant pattern that blended in focally with another minor component. The main pattern is seen here in a low-power view. The dark-staining nests of tumor show central necrosis.
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Find two areas of central necrosis in the nests of tumor cells.
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Figure 2. High-power view of tumor. Find a mitotic figure. Find 2 adjacent apoptotic cells.
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What type of lung cancer is this, and what are the diagnostic features that are shown? Answer
Apoptotic cells with clumped, fragmented chromatin
Tumor type: Small cell carcinoma
The low-power view shows nests of tumor, some with central necrosis. The tumor cells are uniform and do not show evidence of squamous or glandular differentiation. The stroma has some connective tissue and chronic inflammatory cells.
The high-power view shows fairly uniform cells with little cytoplasm. Nuclei have irregular shapes as they are molded against each other. Nuclear chromatin is finely granular, and nucleoli are not seen. This representative field has several mitoses, which reflect the high mitotic rate of this tumor. The dark, fragmented nuclei indicate apoptotic cells. No rosettes were seen.
Summary of Criteria for Diagnosis of Small Cell Carcinoma [1]
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Growth pattern: sheets, nests, trabeculae, rosettes Mitoses: >10/10 high power fields Necrosis: broad areas Nuclear features: usually small to medium-sized and hyperchromatic; giant cells may occur N/C ratio: high |
Nucleoli: inconspicuous Nuclear chromatin: finely granular Nuclear shape: round, angulated, spindled Nuclear smear: common in biopsies Azzopardi sign (see later): may be present |
Reference:
1. Travis W, Gal A, Colby T, Klimstra D, Falk R, Koss M. Reproducibility of neuroendocrine lung tumor classification. Hum Pathol 1998; 29:272-279.
Clinical summary
Image 2