[Schwannoma located in the tongue. A clinical case report]

Schwannoma or neurilemmoma and neurofibroma are two tumors of the peripheral nerves originating in the nerve sheaths. Schwannoma account for just over 1% of benign tumors reported in the oral cavity. The tongue is unanimously considered the most frequent site at this level; however, the tip is the least affected part of the organ. The case of schwannoma reported here is the third observed with a lingual localization in 18 years by the Division of Maxillo-Facial Surgery of The Odontostomatological Clinic of the University of Turin. The case is of interest due the rarity of this pathology and the presence of non-significant symptoms for a presumed initial diagnosis. CASE REPORT. A 21-year-old woman was referred to our attention following the appearance two years earlier of a slowly growing swelling on the tip of the tongue. The patient complained of the fastidious presence, disturbance to mastication and phonation and occasional paresthesia of the tip of the tongue. The small mass, which was clearly evident on examination, was covered with normal mucosa. On palpation it had a hard-elastic consistency; it was slightly painful, smooth and partial mobile on surrounding levels. The patient underwent the surgical removal of the neoplasia under anesthesia. The mass was well capsulated and a good cleavage plane was easily found. The neoformation was yellowy grey, oval bean-shaped, measuring 1.9 x 1.3 x 1.1 cm. The histological diagnosis, confirmed by immunohistochemical tests, was benign Antoni's, type A schwannoma. The postoperative period was good an there was no recidivation during the course of a one-year follow-up. DISCUSSION AND CONCLUSIONS. Benign schwannoma, which are relatively rare in the oral cavity, represent a pathology which are often not taken into account during clinical practice. Symptoms which take the form of slight hypoesthesia and vague paresthesia may lead to the suspected diagnosis of this type of neoplasia. The final diagnosis is always made after a definitive histological examination. Differential diagnosis must be made in relation to malignant tumors (on the basis of anamnestic data relating to the speed of growth and clinical appearance of the neoplasia) and, above all, in relation to numerous benign neoformations based on epithelial and connective tissues (lipoma, fibroma, leiomyoma and adenoma). Treatment is always surgical: in the case reported here, the exeresis of the lesion also allowed its histological characterization (excisional biopsy). Surgery was conservative and did not require local or locoregional prophylactic measures. After the final histological diagnosis of schwannoma, the patient underwent a thorough general objective examination to check the presence of other characteristic signs of Von Recklinghausen's syndrome, have a probability of malignant degeneration ranging between 5 and 16%. Isolated schwannoma hardly ever become malignant and in general, if exeresis is complete, no recidivation occurs after surgery.