Plexiform Neurofibroma (NF1)

Findings:
An infiltrative, mildly expansile mass is evident in the right pre- and postauricular soft tissues. The mass has predominantly high signal characteristics on T2WI and heterogenous isointensity to gray matter on T1WI. The axial T2WI shows high signal foci in the basal ganglia with extension to the internal capsule. An additional small hyperintensity is seen in the left thalamus.

Differential Diagnosis:
The combination of basal ganglia T1 bright spots and infiltrating superficial soft tissue lesion should lead to the diagnosis of NF1. No other reasonable differential exists.

Discussion:
Neurofibromatosis type I- AD, 1/2500, 50% spontaneous mutation
 -clinical dx: 2 or more
        -cafe au lait spots (6 or more, >5mm child, >15 mm adult),
        -NFs 2 or more
        -plexiform NF
        -axillary/intertriginous freckles
        -optic glioma
        -lisch nodules
        -bone lesions
        -relative with NF
-up to 50% of optic nerve gliomas assd with NF1

-cutaneous lesions
        -cafe au lait spots (coast of California, McCune Albright coast of Maine)
        -freckling intertriginous
        -NFs, (TNTC NFs=fibroma molluscum)
        -elephantiasis neuromatosa

-bone findings
        -macrocephaly, lambdoid defect, enlarged neural foramina (with or without NFs) 
        -sphenoid dysplasia
        -posterior vertebral scalloping and scoliosis
        -pseudarthrosis
        -genu valgum/varum
        -ribbon ribs

-tumors
        -ONG
        -cord astrocytomas
        -malignant peripheral nerve sheath tumors
        -embryonal tumors, leukemia, melanoma, medullary thyroid cancer

-other CNS lesions
        -T1 bright spots in GP ?etiology and significance
        -cerebellar hamartomas
        -arachnoid cyst, meningocele

-vascular lesions
        -renal artery stenosis
        -smoothly tapered stenosis/occlusion of visceral arteries
        -coarctation
        -intracranial stenosis

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