Glomus tumour

Glomus tumour
Diagnosis in short
Glomus tumour. H&E stain.
LM	sheets of equally-spaced cells ("cookie cutter appearance"), polygonal cells +/-identifiable cellular borders, thin-walled blood vessels, moderate clear cytoplasm
IHC	SMA +ve (100%), desmin usu. -ve, CD34 -ve, S-100 -ve
Site	skin/soft tissue - classically subungal (under the nail)
Syndromes	+/-neurofibromatosis 1
Symptoms	painful skin lesion, cold intolerance, point tenderness
Prevalence	uncommon
Prognosis	usu. good (benign), rarely malignant
Treatment	excision

Glomus tumours, also known as glomangioma, are painful, perivascular tumour that are classically periungual.

It should not be confused with paraganglioma, which were once called glomus tumour.

This tumour is classified as a perivascular tumour (also pericytic tumour) which is a subset of soft tissue tumours.

General

• Tumour derived from smooth muscle cell.
• Usually benign.
  • Malignant variant exists (known as glomangiosarcoma) - extremely rare.
• May be associated with neurofibromatosis 1.

Clinical - classic triad:

• Pain - see painful skin lesions.
• Point tenderness.
• Cold intolerance.

Gross

Location:

• Classically subungual (under the nail).
  • Reported in almost very site imaginable.
  • Most common GI site: stomach.

Appearance (extradigital tumours):

• Purplish papule.

Microscopic

Features:

• Sheets of equally-spaced cells ("cookie cutter appearance") - key feature.
• Polygonal cells +/- identifiable cellular borders.
• Thin-walled blood vessels.
  • May vaguely resemble antlers (staghorn vessels).
• Moderate clear cytoplasm.

Notes:

• No significant nuclear atypia.
• The regular cell spacing is called "cookie cutter appearance". It looks like the cells were created with a cookie cutter; the spacing between cell is equal and they all look very similar.
• Should be perivascular - abut endothelial cells.
• Myxoid matrix common.

DDx - Why it is not a(n) ...

• Spiradenoma - also vascular and 'blue' but epithelial, often on the head (or at least chest and up).
• Solid and cystic hidradenoma - epithelial and less 'blue'
• Angiosarcoma - has nuclear atypia.
• Dermatofibroma - spindle cell lesion.
• Capillary hemangioma - no epithelioid cells, more blood vessels.

Images

• 

  Glomus tumour - intermed. mag. (WC)

• 

  Glomus tumour - high mag. (WC)

• 

  Glomus tumour - very high mag. (WC)

• 

  Glomus tumour - very high mag. (WC)

www:

• Glomus tumour (ouhsc.edu).

IHC

Features:

• SMA +ve ~ 100%.
• Desmin usu. -ve.
• CD34 -ve.
  • Rarely +ve.

Others:

• S100 -ve.
• Calponin +ve.

Sign out

LESION, RIGHT RING FINGERNAIL, EXCISION:
- GLOMUS TUMOUR.

COMMENT:
The tumour cells are positive for SMA.

Micro

The sections show a tumour composed of polygonal cells with moderately distinct cellular borders and moderate cytoplasm. The tumour cell nuclei are round and have round nucleoli seen with the 10x objective. Thin-walled blood vessels with bland endothelial cells are found within the tumour. Tumour cells are identified immediately adjacent to the endothelial cells. No mitotic activity is apparent. Focal nuclear enlargement is present; however, no significant nuclear atypia is identified.

See also

• Painful skin lesions.
• Myopericytoma - the other perivascular (soft tissue) tumour.