Peripheral nerve sheath tumors arising in salivary glands: A clinicopathologic study

Primary salivary gland peripheral nerve sheath tumors (PNST) are uncommon. This study is a retrospective, clinicopathologic review of 9 cases of PNST (5 neurofibromas, 3 schwannomas and 1 malignant peripheral nerve sheath tumor (MPNST)) arising from the salivary glands, encountered between 1990 and 2015. All patients with neurofibromas were male (ages 1-62 years) and had a single parotid lesion of which 2 were diffuse, 2 plexiform and one mixed diffuse/plexiform. Four had a history of neurofibromatosis I. Four of 5 presented with symptoms related to mass effect including facial swelling, facial drooping, and dysphagia. All underwent de-bulking surgery and recurred due to continued growth. Of the 3 patients with schwannomas, 1 was male and 2 were female (ages 19, 44 and 56 years). One tumor each arose in the sublingual, submandibular, and parotid glands. Two of 3 presented with soreness and swelling local to the affected gland, especially while chewing. There was no recurrence of these tumors after resection. An MPNST in a male presented as a tender mass in the patient's left parotid; the tumor was resected. There was no evidence of tumor elsewhere in the body. The tumor did not recur in 12 years of follow-up. The most common tumor type in the current series was neurofibroma; most arose in the background of neurofibromatosis type I and all of which recurred after initial subtotal resection. Most PNST arose in the parotid gland.