Neuroendocrine carcinoma

Neuroendocrine tumor

Topic Completed: 1 August 2012

Minor changes: 26 August 2021

Copyright: 2002-2021,, Inc.

PubMed Search: Neuroendocrine carcinoma [title] breast

Monika Roychowdhury, M.D.
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Cite this page: Roychowdhury M. Neuroendocrine tumor. website. Accessed October 15th, 2021.
Definition / general
  • Often (although not consistently) refers to cases lacking another specific histologic type, such as solid papillary, mucinous / colloid or micropapillary
  • Also called endocrine carcinoma or solid cohesive neuroendocrine carcinoma
  • Some cases were formerly called carcinoid tumor (Eur J Surg Oncol 1995;21:609)
Clinical features
  • Up to 5% of all breast carcinomas, depending on how defined
  • Frequency increases with age
  • Similar clinical presentation as ductal NOS; i.e. no carcinoid syndrome is present
  • Similar prognosis as ductal NOS
  • Apocrine phenotype (androgen receptor positive in 50% of cells) is present in elderly women (Mod Pathol 2001;14:768)
Case reports
Clinical images

Images hosted on other servers:

10 cm mass

Gross description
  • No distinctive gross features
Microscopic (histologic) description
  • Small, low grade tumor cells in nests separated by fibrous tissue
  • Rarely ribbons, rosettes or mitotic figures
  • Usually no mucin, no DCIS
  • No specific histologic patterns, such as solid papillary, small cell or mucinous / colloid
Microscopic (histologic) images

AFIP images

Ribbon growth pattern with spindled cells

Cells often have argyrophilic
grimeliius+ granules, tumor is
immunoreactive for chromogranin

Contributed by Dr. Semir Vranic

Focal mucin production

Chromogranin expression

Synaptophysin expression

Estrogen receptor

HER2 protein

Neuroendocrine carcinoma of the breast

Images hosted on other servers:

Well differentiated tumor with alveolar growth pattern

Various markers (Fig G, H, I)

(Fig A-D, H-I)

Carcinomatous lymphangitis


Cytology description
  • Markedly cellular with mostly dispersed tumor cells, also some loose clusters, acinus-like formations, small sheets, rosette like formations and ribbons
  • Cells are small and regular with moderate cytoplasm, fairly uniform and round / oval nuclei, often plasmacytoid with eccentric nuclei (Acta Cytol 1994;38:73, Indian J Pathol Microbiol 2007;50:65)
Electron microscopy description
  • Dense core secretory granules
Electron microscopy images

AFIP images

Dense core granules
throughout the
cytoplasm, but increased
at cell membrane

Dense core granules
measure 270 - 430 nm
cluster near cell membrane

Differential diagnosis
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