Forbes, Glenn S.

Restricted exposure and inconsistencies in sinus pneumatization place the optic nerve at risk during operations on the sphenoid sinus and posterior ethmoid cells. In this study, computed tomography was used to examine these relationships. We reviewed 80 patients who underwent high‐resolution computed tomographic scanning for ophthalmologic complaints in which the scan was negative. Forty‐eight percent of posterior ethmoid cells are separated from the optic nerve by the thin bony lamina of the optic canal. Nearly 90% of sphenoid sinuses contact the ipsilateral optic nerve and 10% contact both nerves. Eight percent of posterior ethmoid cells override the ipsilateral sphenoid sinus and contact the optic nerve on that side. Paraxial reformatted displays allowed estimation of the degree of projection of the optic nerve into adjacent sinus cavities. Three percent of optic nerves have significant projection into the posterior ethmoid cell, and 23% project significantly into the sphenoid sinus. The width of the bony plate that separates the optic nerve from the sinus cavity was the same for sphenoid and ethmoid sinuses. Although sinus pneumatization varies among individuals, right and left sides are generally similar within one person.

Abstract Fibromatoses are uncommon infiltrative lesions affecting musculoaponeurotic structures, most often of the limbs and trunk. Lesions involving the cranial cavity are rare and require the same aggressive surgical management as elsewhere in the body. This case illustrates their clinical and neuroradiological features and underscores the necessity for aggressive resection to avoid recurrence. The literature is reviewed. (Neurosurgery 29:123-126, 1991)

Abstract A unique gliomesenchymal neoplasm, consisting of a subependymoma, a form of low-grade glioma, and a rhabdomyosarcoma, is described. It arose and recurred in the brain stem of a 52-year-old man. Immunohistochemical studies demonstrated the presence of a neuroectodermal marker S-100 protein within some sarcoma cells. The occurrence of this rare tumor supports the concept that striated muscle may derive from a neuroectodermal precursor lesion.