Neurofibromas are tumors consisting of a proliferation of peripheral nerve/s that can affect almost any organ, soft tissue, bone, or anatomical site including, quite commonly, skin. The widespread, systemic manifestation of this disease is called Neurofibromatosis which is a ubiquitous and protean disease. Within the orbit/eyelids, this abnormal proliferation of the peripheral nerve Schwann cells and endoneural fibroblasts and collagen [underlying pathologic change causing the disease] can lead to a distortion of the bony anatomy [eye socket] and soft tissue [eyelids]. This can lead to mild, moderate, or severe disfiguration. This distortion can, in turn, threaten the function of the eyeball leading to vision loss and even total blindness.

Treatment

There is no cure for this disease. Individual lesions can be addressed with surgical excision. In cases of isolated, circumscribed lesions, the neurofibroma can be excised in total. Plexiform lesions are much more difficult to address and usually can be only partially removed [debulked]. Recurrence and regrowth is common, and a complete removal of the eye socket tissue is a potential endstage treatment of the disease in cases of severe disfiguration and complete vision loss.

To preserve vision, intraocular pressure needs to be controlled to prevent progressive glaucoma. This may involve topical pressure-lowering agents (eye drops), laser surgery, or scalpel surgery. Often, this can slow the progression of disease, but usually cannot halt vision loss, but decrease its rate.

Although neurofibromas can be isolated, more commonly it is a widespread systemic condition labeled Neurofibromatosis. Neurofibromatosis is a disease of genetic origin [autosomal dominant transmission with complete penetrance but variable expressivity] which has been isolated to chromosome 17 [Type I or Peripheral] or Chromosome 22 [Type 2 or Central].

As Neurofibromatosis is a genetic disease, a positive family history is the most important risk factor of disease. Although the disease is autosomal dominant, expressivity is variable. This means that severity/extent of the disease is variable.

The diagnosis of a single neurofibroma is a pathologic one, for example, it has to be examined under the microscope.

Clinically, orbital manifestations of neurofibromas can be the more common plexiform variety, or the less common isolated/solitary neurofibroma. Plexiform neurofibromas can affect the entire orbit causing eyeball malposition, but the eyelid manifestations are more obvious and detected earlier. This involves a visible or palpable eyelid mass, often in cords or nodules which with growth can give the upper eyelid an S-shaped configuration due to abnormal stretching of the tissue. This ropy mass can be likened to a “bag of worms”. Pulsation of the eye socket can be present secondary to absence of orbital bone near the brain (sphenoid wing0.

However, systemic Neurofibromatosis encompasses a variety of physical findings. Briefly, Neurofibromatosis I presents with pigment skin spots (café au lait), axillary freckles, iris Lisch nodules, cutaneous neurofibromas, and facial asymmetry, among others.

Neurofibromatosis II maybe more subtle and often involves other tumors in the intracranial/intraspinal tumors such as meningioma, acoustic neuroma, astrocytoma and ependymoma.

A complete skin and ocular examination is needed along with other tests such as CT scans of the bran, orbit. Biopsy of a lesion will confirm the diagnosis pathologically.

As this is a space-occupying lesion, there can be various systemic complications of this disease. Within the orbit/eyelids, this disease can be subtle at best, and quite disfiguring at worst. Loss of vision is a serious and not uncommon complication of this disease, from optic neuropathy due to compression of the optic nerve, or glaucoma because of abnormal aqueous outflow leading to significant rises in intraocular pressure.