Lymph nodes & spleen, nonlymphoma

Ectopic tissue / inclusions

Epithelial inclusions

Last author update: 1 March 2014
Last staff update: 18 July 2022

Copyright: 2003-2024,, Inc.

PubMed Search: Epithelial inclusions lymph nodes

Jayalakshmi Balakrishna, M.D.
Page views in 2023: 2,836
Page views in 2024 to date: 831
Cite this page: Balakrishna J, Sharabi A. Epithelial inclusions. website. Accessed April 14th, 2024.
Definition / general
  • Also called benign metastasis or heterotopia
  • Axillary, cervical, mediastinal, mesenteric, para-aortic, pelvic, renal lymph nodes
  • Different theories regarding the pathogenesis:
    • Benign metastasis
    • Developmental heterotopia
    • Metaplasia of multipotent cells
    • Iatrogenic displacement and transport (J Clin Oncol 2006;24:2013)
Clinical features
  • Asymptomatic, incidental finding
Prognostic factors
  • Benign with no significant clinical implications
  • Rarely may undergo disease processes and become cystic, a benign tumor or malignant
Case reports
  • No specific treatment needed, unless associated with another disease
Gross description
  • Normal unremarkable lymph nodes
Microscopic (histologic) description
  • Reactive follicular hyperplasia
  • Well formed epithelial formations, in or near the peripheral sinuses
  • Examples include salivary gland, thyroid follicles, breast tissue, respiratory type epithelium, fallopian tube lining or endometrium
  • Single or tubules of epithelial cells in subcapsular sinus of draining lymph node after surgical or needle manipulation (Am J Clin Pathol 2000;113:259)
  • Also hemosiderin laden macrophages and damaged erythrocytes
Microscopic (histologic) images

AFIP images
Missing Image

Mammary epithelial
inclusion in axillary
lymph node

Positive stains
  • Keratins and specific markers for the cell lineage
Back to top
Image 01 Image 02