Hamartoma

Micrograph of a pulmonary hamartoma. H&E stain.

A hamartoma is a:[1][2]

  1. Disorganized (non-neoplastic) growth (that may mimic a true neoplasm).
  2. Composed of tissue of the region within it is found.

Note 1

  1. If #2 does not apply it is a choristoma.
  2. "Disorganized" in #1 separates it from:
    • Hypertrophy and hyperplasia - which may be physiologic processes.
  3. The key differences between cancer and hamartoma are the ability of cancer to:
    • Invade/destroy surrounding tissue.
    • Metastasize.
  4. Considered clinically, growth is the difference between a benign tumour (measurable growth rate) and a hamartoma (no growth vis-à-vis the surrounding tissue).
  5. Hamartomas often consist of:
    • Multiple cell types, e.g. Peutz-Jeghers polyps consist of normal submucosal elements.
    • Have a well-circumscribed border.

Note 2

There is much confusion in this area as:

  • Clonality is usually considered a characteristic of neoplasms.
  • The line between benign tumour and hamartoma is thin, if one considers that a hamartoma can be clonal and some benign tumours have a slow growth rate.
  • If one considers choristoma (hamartoma's cousin), the line between benign tumour (e.g. teratoma/dermoid cyst) and choristoma is thin.

A more useful definition of hamartoma might be:

  1. Architecturally disorganized tissue that appears to be native to the site.
  2. No significant growth (vis-à-vis the surrounding tissue).

Contents

Site specific

See also

References

  1. URL: http://www.medterms.com/script/main/art.asp?articlekey=84157. Accessed on: 22 November 2010.
  2. Mitchell, Richard; Kumar, Vinay; Fausto, Nelson; Abbas, Abul K.; Aster, Jon (2011). Pocket Companion to Robbins & Cotran Pathologic Basis of Disease (8th ed.). Elsevier Saunders. pp. 147. ISBN 978-1416054542.