ABSTRACT
Tumors in this category that are considered here are schwannomas and neurofibromas, both benign neoplasms, and malignant peripheral nerve sheath tumors.
SCHWANNOMAS Schwannomas are common tumors attached to peripheral and cranial roots or nerves, particularly sensory nerves. In neuropathological practice they are most commonly encountered attached to the vestibular (eighth) nerve. Most such schwannomas are sporadic, but multiple schwannomas, particularly bilateral acoustic schwannomas, occur in the inherited tumor syndrome, neurofibromatosis type 2 (NF2). Bilateral vestibular schwannomas (Fig. 13.1) are pathognomic of NF2. The spinal varieties often present with radicular pain. Those on the eighth nerve present with hearing difficulty or tinnitus. They vary greatly in size from less than a centimeter to 10 cm across. They are firm, pale, and well demarcated (Fig. 13.2). The cut surface may show small cysts, foci of old hemorrhage, or foci of yellow discoloration representing clusters of lipid-laden macrophages (Fig. 13.3).
