Melanotic schwannoma

A.Prof Frank Gaillard et al.

Melanotic schwannomas are uncommon, and more frequently aggressive,  variants of schwannomas, usually encountered in somewhat younger individuals 1.

Melanotic schwannomas occur in two forms depending on the presence or absence of psammoma bodies

  1. non-psammomatous melanotic schwannoma
  2. psammomatous melanotic schwannoma
Non-psammomatous melanotic schwannoma

Non-psammomatous melanotic schwannomas almost invariably affect the spinal nerves and paraspinal sympathetic ganglia 1,2

Psammomatous melanotic schwannoma

Psammomatous melanotic schwannoma also arise from spinal nerves and paraspinal ganglia, but may also involve cranial nerves and visceral autonomic nerves 1

Approximately half of individuals diagnosed with these tumours have underlying Carney complex 1-3

Macroscopic appearance

Melanotic schwannomas appear as well circumscribed masses of variable pigmentation ranging from grey to black, depending on the amount of melanin 3

Microscopic appearance

Melanotic schwannomas are composed of Schwann cells which contain melanosomes 1,2. Psammomatous tumours also contain psammoma bodies 3.

MRI

The appearances of melanotic schwannomas are similar to conventional schwannomas except that they usually have intrinsic high T1 signal and T2 signal loss due to the presence of melanin 4

Although generally indolent, approximately 10% of melanotic schwannomas are malignant 1,3. Complete resection is usually curative 3

Share article

Article information

rID: 53324
Synonyms or Alternate Spellings:
  • Psammomatous melanotic schwannoma
  • Non-psammomatous melanotic schwannoma
  • Pigmented schwannoma
  • Melanotic nerve sheath tumour
  • Melanogenic schwannoma

Support Radiopaedia and see fewer ads

Updating… Please wait.
Loadinganimation

Alert accept

Error Unable to process the form. Check for errors and try again.

Alert accept Thank you for updating your details.