Small Cell Carcinoma
Small cell carcinomas are highly malignant tumors composed of relatively small uniform cells with scant cytoplasm and stippled nuclear chromatin pattern. An ultrastructural hallmark of these tumors is the presence of membrane-bound, electron-dense granules that contain a variety of active peptide moieties. Small cell carcinomas occur in middle age and older individuals with a mean age of 59 years. Cough, hemoptysis and chest pain are symptoms associated with the development of tumor masses in the lung. On chest radiographs and computed tomography (CT), small cell carcinomas appear as hilar or perihilar masses, often in continuity with mediastinal lymphadenopathy and lobar collapse. A small percent of tumors are peripherally located and in these instances the radiographic presentation will be that of a solitary lung nodule. Positron Emission Tomography (PET) scanning is useful in patients with extensive disease and also in the determination of prognosis.