Adamantinoma

Adamantinoma is an uncommon benign bone tumour. It should not be confused with adenomatoid tumour.

Adamantinoma
Diagnosis in short
Adamantinoma. H&E stain.
LM	biphasic tumour - epithelial component & fibro-osseous component
Subtypes	classic, differentiated
Site	bone - classically tibia, other sites
Prevalence	uncommon
Prognosis	benign +/-locally aggressive
Clin. DDx	osteosarcoma

General

Features:

• Rare: < 1% of bone tumours.
• Typically 25-35 years old.
• Benign, may be locally aggressive.

Gross

• Classically mid portion of tibia.
  • Fibula common.
  • Reported in many other sites.

Radiology

• Intracortical, radiolucent.

Microscopic

Features:

• Biphasic tumour:
  1. Fibro-osseous component.
     • Spindle cells.
  2. Epithelial component.
     • Classically nests of basaloid cells.

Note:

• It is described as resembling ameloblastoma, but the resemblance isn't striking.

DDx:

• Vascular tumours (epithelioid hemangioendothelioma).
• Metastatic carcinoma.

Subtypes

Subdivided into:

• Classic.
• Differentiated - less than 20 years old only.

Images

• 

  Adamantinoma - intermed. mag. (WC)

www:

• Adamantinoma (southbaypath.org).
• Adamantinoma (nih.gov).
• Adamantinoma (nih.gov).

IHC

Features:

• CK14 +ve (HMWK).
• CK19 +ve (LMWK).
• CK8/18 -ve (LMWK).

See also

• Chondro-osseous tumours.