Lung tumor
Carcinoid and related tumors
Atypical carcinoid tumor




Topic Completed: 1 September 2012

Revised: 31 January 2019, last major update September 2012

Copyright: (c) 2003-2016, PathologyOutlines.com, Inc.

PubMed Search: atypical carcinoid tumor lung
Page views in 2018: 7,313
Page views in 2019 to date: 2,546
Cite this page: Jain D. Atypical carcinoid tumor. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/lungtumoratypicalcarcinoid.html. Accessed April 21st, 2019.
Definition / general
  • Also called moderately differentiated neuroendocrine carcinoma
  • Diagnostic criteria (Rosai): resembles a carcinoid but with atypical features
  • More aggressive than typical carcinoid tumors: nodal metastases in 70% vs. 5%
  • 5 year survival is 49-69%
Microscopic (histologic) description
  • Carcinoid tumors with increased mitotic activity (2-10 per 10 HPF), nuclear pleomorphism or foci of necrosis
Microscopic (histologic) images

Images hosted on other servers:

Various images

Various immunostains with various tumors


Atypical carcinoid tumor of lung metastatic to adrenal gland

Positive stains
Negative stains
Electron microscopy description
  • Numerous large neurosecretory granules
Differential diagnosis
Back to top