تويت
Small cell carcinoma of the Lung
It accounts for about 20-25% of primary lung carcinomas; most of the patients are smokers. This tumor is often widely metastasizing and the prognosis is poor.
Small cell carcinoma is a neuroendocrine neoplasm; ultrastructurally, the cells contain cytoplasmic dense-core granules which stain positive with neuroendocrine markers (such as chromogranin).
Small cell carcinoma is classically composed of small, round to fusiform cells with scant cytoplasm. Necrosis, a high mitotic rate and nuclear encrustation of vascular walls are characteristic features. Cells of intermediate variant are larger, with more cytoplasm and vesicular nuclei.
Cytologic diagnostic features (sputum and bronchial washing)
•Enlongated grouping of small dissociating tumour cells (twice the size of lymphocytes; occasionally larger)
•Scanty cytoplasm, irregular carrot-shaped, hyperchromatic nuclei, showing molding
•Coarse chromatin, incospicuous nucleoli
•Mitosis
•Degenerative changes
•Local tumour diathesis
Immunocytochemistry
•Neuroendocrine markers + (Chromogranin A, CD56, NSE, Synaptophysin)
•Cytokeratin 7 +
•Cytokeratin 5 –
•Cytokeratin 20 –
•TTF-1 +
It accounts for about 20-25% of primary lung carcinomas; most of the patients are smokers. This tumor is often widely metastasizing and the prognosis is poor.
Small cell carcinoma is a neuroendocrine neoplasm; ultrastructurally, the cells contain cytoplasmic dense-core granules which stain positive with neuroendocrine markers (such as chromogranin).
Small cell carcinoma is classically composed of small, round to fusiform cells with scant cytoplasm. Necrosis, a high mitotic rate and nuclear encrustation of vascular walls are characteristic features. Cells of intermediate variant are larger, with more cytoplasm and vesicular nuclei.
Cytologic diagnostic features (sputum and bronchial washing)
•Enlongated grouping of small dissociating tumour cells (twice the size of lymphocytes; occasionally larger)
•Scanty cytoplasm, irregular carrot-shaped, hyperchromatic nuclei, showing molding
•Coarse chromatin, incospicuous nucleoli
•Mitosis
•Degenerative changes
•Local tumour diathesis
Immunocytochemistry
•Neuroendocrine markers + (Chromogranin A, CD56, NSE, Synaptophysin)
•Cytokeratin 7 +
•Cytokeratin 5 –
•Cytokeratin 20 –
•TTF-1 +
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