Primary Diagnosis

Neurofibromatosis Type I

Secondary Diagnosis

N/A

Diagnosis Discussion

Neurofibromatosis (NF) is an autosomal dominant disorder, probably of neural crest origin, that affects all 3 germinal layers; therefore, it can involve any organ system. NF is not a single entity but a group of heterogeneous multisystemic neurocutaneous disorders involving both neuroectodermal and mesenchymal derivatives. Although 8 subtypes have been proposed to date, the National Institutes of Health (NIH) Consensus Development Conference has defined 2 distinct types: neurofibromatosis type 1 (NF1), or von Recklinghausen disease, which affects 85% of patients, and neurofibromatosis type 2 (NF2), or bilateral acoustic neuromas/schwannomas, which affects 10% of patients. Neurofibromas may affect any organ in the body. Discrete cutaneous and subcutaneous neurofibromas may develop at any time in life, but they occur infrequently before puberty. The total number of neurofibromas seen in adults with NF1 varies from a few to hundreds or even thousands. Additional cutaneous and subcutaneous neurofibromas continue to develop throughout life, although the rate of appearance may vary greatly from year to year. Although schwannomas and neurofibromas are histologically different, they exhibit similar MRI appearances. Both schwannomas and neurofibromas are hypointense or mildly hypointense compared to the spinal cord on T1-weighted images and heterogeneously hyperintense on T2-weighted images. The tumors may extend into the neural foramina. Within schwannomas, areas of hypointensity due to collagen deposition, hemorrhage, and densely packed Schwann cells frequently are seen. After the administration of contrast material, peripheral enhancement of schwannomas predominates. Neurofibromas enhance more homogeneously. Enhancement patterns and T2-weighted images can help differentiate schwannomas from meningiomas, but the same confidence cannot be transferred to differentiating schwannomas from neurofibromas. MRI allows noninvasive identification of intradural neurofibromas and helps determine their relationship to the neural foramina, canal, and thecal sac spinal cord. Paraspinal neurofibromas may be dumbbell shaped, fusiform, or spherical. They are slightly hyperintense relative to muscle on T1-weighted images, with a hyperintense periphery and a hypointense core on T2-weighted images. Source: www.emedicine.com/RADIO/topic474.htm.

General Anatomic Area:

Cervical

Secondary Anatomic Area:

N/A

Disease Category:

Neoplastic - primary

Contributor:

Erin Simon, MD

Date:

09/01/2005

Difficulty Level:

Easy

Pathology Confirmed?:

Yes
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ACR Category Number:

N/A

Keywords:

neurofibroma, neurolemmomma, nerve sheath tumor, phakomatosis, elephant mans disease, von recklinghausens disease