Thymic carcinoma
Small cell carcinoma

Topic Completed: 1 December 2012

Minor changes: 7 February 2020

Copyright: (c) 2003-2018,, Inc.

PubMed Search: Small cell carcinoma[TI] mediastinum

Hanni Gulwani, M.B.B.S.
Page views in 2019: 349
Page views in 2020 to date: 201
Cite this page: Gulwani H. Small cell carcinoma. website. Accessed May 28th, 2020.
Definition / general
  • Rare, less than 100 well documented primary cases in mediastinum
  • If metastatic, may have symptoms due to primary intrabronchial tumor (cough, hemoptysis, dyspnea) or esophageal tumor (dysphagia)
  • Also called oat cell carcinoma, undifferentiated neuroendocrine carcinoma
  • Occurs anywhere in mediastinum, usually metastatic from lung or esophagus
Clinical features
  • May have paraneoplastic syndrome (Cushing syndrome, syndrome of inappropriate antidiuretic hormone)
Prognostic factors
  • Almost always fatal, although median survival is 36 months
Case reports
Gross description
  • Fleshy, gray-white (similar to lymphoma), hemorrhagic, necrotic
Microscopic (histologic) description
  • Centered in thymus (suggests primary) or nodal
  • Clusters of small blue cells with minimal cytoplasm, hyperchromatic nuclei, no / minimal nucleoli, nuclear molding, frequent mitotic figures, frequent necrosis, crush artifact common, encrustation of basophilic nuclear material around intratumoral blood vessels (Azzopardi phenomenon)
  • May be mixed with squamous cell carcinoma or adenocarcinoma
Positive stains
Negative stains
Electron microscopy description
  • Uniformly sized (80 - 250 nm) neurosecretory granules with a peripheral halo, usually in clusters, primitive junctional complexes
Differential diagnosis
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