In general, the neurofilament (NF) immunostain is useful for detecting the cytoplasmic projections of mature neuronal cells (e.g. axons), either within the CNS or PNS.
This can be applied to the differential diagnosis of neurofibroma vs schwannoma (neurofibromas are more likely to have intratumoral axons). It can also be used to detect CNS infarction (loss of NF staining). In conjunction with luxol-fast blue, it is also great for diagnosing demyelinating disease within CNS specimens (MS plaques will show preserved NF staining with loss of LFB staining.
Of note, relatively immature/primitive neuronal cells (neuroblastoma or medulloblastoma) show significantly lower levels of staining.
Formalin-fixed, paraffin-embedded tissue blocks (FFPE). If tissue blocks are not available, unstained slides are acceptable (please submit 1–2 slides per antibody to be tested, cuts must be 4 microns thick).
Tissue removed during a surgical procedure and placed in 10% NBF soon after removal from the patient. Appropriate tissue for requested staining.
Slides or paraffin blocks with no tissue remaining. Samples fixed in fixatives other than 10% neutral buffered formalin. Paraffin blocks that have been overheated or frozen.
IHC, Ventana Ultra Stainer
Blocks: 10 years
Slides: 10 years
*The listed CPT codes are for reference use only. Final coding is based on CPT guidelines and individual circumstances.