Expanded teased nerve fibre pathological conditions in disease association.

OBJECTIVE: To describe an expanded teased nerve fibre classification in disease association. METHODS: We reviewed four newly proposed teased nerve fibre types (Types J-M): Type J, rope-like fibres; K, fibril-like clumps of osmium positivity; L, cellular debris along and within nerve fibres; M, circular axonal inclusions surrounded by thin myelin. Different clinical pathological entities were studied for these fibre types including chronic inflammatory demyelinating polyradiculoneuropathy (CIDP: N=20); amyloid polyneuropathy (N=20); intraneural B-cell lymphoma (N=20) or adult-onset polyglucosan body disease (APBD: N=6) in comparison with 112 disease controls. Student's t-test was used to test significance of association between the identified fibre types and the specific clinical diagnosis. RESULTS: Each fibre type significantly associated (p<0.001) with particular disease categories: Type J, 60% of CIDP cases; Type K, 75% of amyloid cases; Type L, 75% of intraneural lymphoma cases; Type M, 100% of APBD cases. Rarely were these fibres found in the other disease control cases ≤3% of cases. In three cases, the teased fibre findings were so striking additional paraffin nerve preparations were made to make the pathological diagnosis when initial paraffin sections were non-diagnostic. CONCLUSIONS: Teased nerve fibre Types J-M associate with commonly seen pathological diagnosis and are helpful in the consideration of specific neuropathy diagnoses.