Neurofibroma at T10

This otherwise healthy 34-year-old man presented with lower thoracic and right flank pain of 2 weeks' duration. The pain followed a T10 dermatomal pattern. He had no other neurologic deficits or signs of neurofibromatosis.

An axial CT image at the level of T10 (A) and an axial MRI scan (B) both showed a soft tissue mass widening the neural foramen on the right and extending in a paraspinal location. A sagittal MRI scan also showed widening of the neural foramen (C). The tumor had no mass effect on the spinal cord. An MRI scan of the brain showed no optic nerve glioma or sphenoid bone dysplasia.

A preoperative evaluation revealed none of the diagnostic criteria for type 1 neurofibromatosis. The patient underwent a right T10/T11 facetectomy and resection of the epidural tumor. Unilateral short-segment pedicle screw internal fixation was used for stabilization after the right T10 inferior and T11 superior facets were removed (D).

The pathologic diagnosis of the resected mass was slow-growing fusiform neurofibroma without the plexiform changes frequently seen in type 1 neurofibromatosis.

Will Beringer, DO, of Bloomington, Ill, writes that while this patient did not have type 1 neurofibromatosis, approximately 50% of solitary neurofibromas are associated with the disease. This autosomally dominant disorder has variable penetrance and affects about 1 in 3500 persons.^1,2 According to the NIH, the diagnosis of type 1 neurofibromatosis requires 2 or more of the following³:

• Six or more caf au lait macules, larger than 5 mm in prepubertal persons and larger than 15 mm in postpubertal persons.

• Two or more neurofibromas of any type, or a single plexiform neurofibroma.

• Axillary or inguinal freckling.

• Optic glioma.

• Two or more Lisch nodules (iris hamartomas of melanotic origin).

• A distinctive osseous lesion, such as sphenoid dysplasia or thinning of the long bone cortex with or without pseudoarthrosis.

• An immediate family member with type 1 neurofibromatosis.

The hallmark lesions of type 1 neurofibromatosis are caf au lait macules and multiple firm, subcutaneous neurofibromas. These lesions may be disfiguring and tender, but they rarely become malignant.

This patient had a rapid, full postoperative recovery. He has no radicular pain, and sensation over his right T10 dermatome is nearly normal.

References:

REFERENCES:

1.

Woodruff JM, Kourea HP, Louis DN, Scheithauer BW. Neurofibroma. In: Kleihues P, Cavenee WK, eds.

World Health Organization Classification of Tumours: Pathology and Genetics of Tumours of the Nervous System.

Lyon, France: IARC Press; 2000: 167-168.

2.

Angelov L, Feldkamp MM, Guha A. Peripheral nerve tumors. In: Kaye AH, Black PM, eds.

Operative Neurosurgery.

London: Churchill Livingstone; 2000:2155-2167.

3.

Stumpf DA, Alksne JF, Annegers JF, et al. Neurofibromatosis. Conference statement. National Institutes of Health Consensus Development Conference.

Arch Neurol.

1988;45:575-578.