title: Nerve pathologic features differentiate POEMS syndrome from CIDP.
abstract: The objective of this study is to determine if the nerve pathology in patients with POEMS syndrome is different from CIDP. We hypothesized that nerve biopsies from patients with POEMS syndrome would have more small vessels and axonal degeneration but less inflammation than CIDP.We performed a retrospective analysis of nerve biopsies performed on "classic" CIDP and POEMS cases. Nerve biopsies were blinded and reviewed by two of the authors (EAP, PJBD). Teased fibers, paraffin-embedded sections, semithin sections and immunostains were analyzed. Small endoneurial and epineurial vessels were counted on paraffin sections with smooth muscle actin (SMACTIN) preparation to judge for neovascularization.A total of 61 cases (35-POEMS, 26-CIDP) were included. The POEMS-group had significantly higher axonal degeneration and fewer normal myelinated fibers on teased fiber preparations. The CIDP-group had significantly more endoneurial mononuclear inflammation on paraffin sections and immunostains. Large onion-bulbs were present only in CIDP cases. A significantly higher number of epineurial vessels was present in POEMS biopsies, with a total count of 120 epineurial vessels predicted as best cutoff to differentiate both conditions (77 % specific and 54 % sensitive).In conclusion, nerve biopsy can be helpful in distinguishing POEMS syndrome from CIDP. POEMS syndrome demonstrates more axonal degeneration and epineurial neovascularization whereas CIDP has greater endoneurial inflammation and onion-bulb formation. These findings support the idea that there are differing underlying mechanisms for these disorders, POEMS being related to paraneoplastic vasculopathy associated with angiogenic factors and CIDP related to inflammatory demyelination.
authors: University of Nebraska Medical Center, 988435 Nebraska Medical Center, Omaha, NE, 68198-8435, USA.
authors: Ezequiel A
authors: EA
authors: Piccione
authors: Mayo Clinic, Department of Neurology, 200 First Street SW, Rochester, MN, 55905, USA.
authors: Janean
authors: J
authors: Engelstad
authors: Mayo Clinic, Department of Neurology, 200 First Street SW, Rochester, MN, 55905, USA.
authors: Peter J
authors: PJ
authors: Dyck
authors: Mayo Clinic, Department of Neurology, 200 First Street SW, Rochester, MN, 55905, USA.
authors: Michelle L
authors: ML
authors: Mauermann
authors: Mayo Clinic, Department of Medicine, Division of Hematology, 200 First Street SW, Rochester, MN, 55905, USA.
authors: Angela
authors: A
authors: Dispenzieri
authors: Mayo Clinic, Department of Neurology, 200 First Street SW, Rochester, MN, 55905, USA. Dyck.PJames@mayo.edu.
authors: P James B
authors: PJ
authors: Dyck
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009389:Neovascularization, Pathologic / Q000473:pathology; D009410:Nerve Degeneration / Q000473:pathology; D016878:POEMS Syndrome / Q000175:diagnosis* / Q000473:pathology*; D010525:Peripheral Nerves / Q000473:pathology*; D020277:Polyradiculoneuropathy, Chronic Inflammatory Demyelinating / Q000175:diagnosis* / Q000473:pathology*; D011984:Sensory Receptor Cells / Q000473:pathology; D016037:Single-Blind Method; D012867:Skin / Q000294:innervation; D055815:Young Adult
keywords: CIDP; Demyelination; Neovascularization; POEMS; VEGF