Images of Sensory and Autonomic Small Fiber Neuropathy

Intraepidermal nerve fibers in skin biopsy:

Full width view of a 3 mm punch biopsy from the thigh with intraepidermal nerve fibers (arrow) visualized by immunohistochemical labeling for PGP9.5 (above).

Normal IENFD:

A higher magnification of small nerve fibers (arrow) in the epidermal layer of a skin biopsy with normal intraepidermal nerve fiber density (IENFD). Arrow head points to the basement membrane that separates the epidermis from the dermis.

Abnormal IENFD:

Skin with abnormally low intraepidermal nerve fiber density, consistent wtih small fiber neuropathy.

Axonal Bulbing:

This image demonstrates skin with significantly reduced epidermal nerve fiber density, consistent with small fiber neuropathy. The small arrowhead points to the epidermal nerve fiber and just below is an axonal swelling.

The mechanism of axonal swelling is not known, but it may be related to slowing of axonal transport during axonal degeneration. They may also be seen in regenerating axons and may have more than one cause.

Amyloidosis:

Amyloidosis in skin of patient with amyloid neuropathy, as detected by Congo Red stain. Arrow points to the amyloid deposits.

Amyloidosis:

Amyloidosis observed with polarizing light microscopy. The arrow points to the apple-green birefringence of the amyloid deposit, previously detected by Congo Red staining, confirming the diagnosis.