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.