Epithelioid Schwannoma of a Spinal Nerve Root.

Even though the diagnosis of schwannoma is usually straightforward in lesions with classic features, tumors with predominantly epithelioid morphology or marked myxoid change may present a diagnostic challenge. There are relatively few reported cases of epithelioid schwannoma entirely lacking classic morphology, and these have occurred in subcutaneous tissues, mucosal surfaces, or as gastrointestinal polyps. Within the spinal cord, caution must be taken to avoid misclassification of this entity as a mesenchymal neoplasm or malignant peripheral nerve sheath tumor, more commonly present with epithelioid morphology.