Lung tumor
Carcinoid and related tumors
Atypical carcinoid tumor

Author: Deepali Jain, M.D. (see Authors page)

Revised: 28 December 2016, last major update September 2012

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

PubMed Search: atypical carcinoid tumor lung
Cite this page: Atypical carcinoid tumor. PathologyOutlines.com website. http://pathologyoutlines.com/topic/lungtumoratypicalcarcinoid.html. Accessed February 23rd, 2017.
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%
Micro Description
  • Carcinoid tumors with increased mitotic activity (2-10 per 10 HPF), nuclear pleomorphism or foci of necrosis
Micro 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