Wide neuralforamina is associated with:
A i.e. Neurofibromatosis Neurofibromatosis type 1 is associated with widening (enlargement) of neural foraminaQ (mostly secondary to dumbbell neurofibroma along exiting spinal nerve root or less commonly d/t dural ectasia, arachnoid cyst or lateral menngocele)Q, scalloping of posterior veebral bodies, enlargement of internal auditory canal (d/t dural dysplasia), enlargement of optic foramen (d/t optic glioma), enlargement of orbital margins & superior orbital fissure (d/t plexiform neurofibroma) and sclerosis of optic foramen (d/t optic nerve sheath meningioma). NF1 causes empty orbitQ, Herlequin appearance of orbit and herniation of middle cranial fossa structures into orbit d/t sphenoid bone hypoplasia. Both neurofibromas (common in NF1) and Schwannomas (common in NF2) are benign nerve sheath tumors mostly found in intradural extramedullary location. Both are derived from Schwann cells, however, neurofibromas also have colagen & fibroblasts. Vestibular or acoustic Schwannoma (or neurilemmoma or acoustic neuroma of 8th cranial nerve) seen in NF2 1/t internal auditory canal (IAC) enlargement (erosion d/t mass centered on long axis of IAC forming acute angles with dural surface of petrous bone) and widening or obliteration of ipsilateral cerebello pontine angle cistern. NF-2 is located on chromosome 22 and NF1 on chromosome 17(Mn 1 for 1 & 2 for 2). NF2 have propensity for developing MEN/MES i.e. meningioma, ependymoma (gliomas) and Schwannoma (neuromas). Nerves without Schwann cells are olfactory and optic nerve. Schwannomas neurofibromas, on CT, appear as sharply marginated, unilateral, spherical, or lobular posterior mediastinal mass, with pressure erosion of adjacent rib or veebral bodies or enlargment of neural foramen with occasional punctate intralesional calcifcation. Owing to their high lipid content, interstitial fluid and areas of cystic degeneration - Schwannomas are often of lower attenuation than skeleton muscle. Neurofibromas are often more homogenous & of higher attenuation than schwannomas (owing to fewer of above histological features). These may heterogenously enhance on contrast administration. On MRI both show variable intensity on T1WI but typically have similar signal intensity to the spinal cord. On T2WI these characteristically have high signal intensity peripherally and low signal intensity centrally (target sign) owing to collagen deposition. Both schwannoma & neurofibroma enhance on gadolinium administration.
Neurofibromatosis type 1
Sturge-Weber syndrome
Von Hipple Lindau disease
Tuberous sclerosis