Small Cell Carcinoma
In small cell lung carcinoma (SCLC), the tumor cells are small (usually less than 3 times the diameter of small resting lymphocytes), round, oval or spindle shaped with scant cytoplasm and ill-defined cytoplasmic borders. Nuclei are hyperchromatic with finely dispersed granular chromatin (salt and pepper appearance). Nucleoli are absent or inconspicuous. Nuclear molding is a constant finding. Mitotic activity is increased. Necrosis is usually present. Exceptions to the typical histologic features mentioned above do occur; occasional cases may have larger tumor cells with more abundant cytoplasm or scattered prominent nucleoli.