Benign Triton Tumor: A Rare Entity in Head and Neck Region
A 14-year-old boy presented with asymptomatic swelling of the chin that had been occurring over 18 months. The lesion gradually increased to involve the left side of the lower lip. There was no history of similar lesions elsewhere in the patient or his family members. There was no history of pain, alteration in speech or difficulty in speaking.\nOn examination, there was a skin colored, non-tender, firm and irregular swelling over the left mentolabial groove extending onto the lower lip (). There was bulging of the left part of the lower lip with distortion of the lip architecture even on occlusion of the lips. The mass produced an irregular, smooth protrusion on the mucosal surface of the lower lip without any discoloration. There was no local depigmentation or hypertrichosis. There was no evidence of freckles or café au lait macules and no bruit over the lesion. Clinically a diagnosis of neurofibroma was made and excisional biopsy under local anesthesia and aseptic conditions was performed. The specimen was sent for histopathological examination.\nGross observation showed that the tumor consisted of a skin covered nodule measuring 1×0.5×0.5 cm. The cut surface was solid grey white. Histopathology sections showed an unremarkable superficial skin and a sub-epithelial tumor. The tumor was ill defined and consisted of fascicles of mature nerve tissue arranged in a multinodular pattern separated by fibrocollagenous septa. The cells were seen surrounding the pilosebaceous unit. The nerve fascicles showed an intricate admixture, with mature striated skeletal muscle bundles of varying sizes ranging from 15 to 20 µm with some being up to 50 µm (, ). Few muscle fibers were seen to be contained within the perineural sheath (). Areas of myxoid change were noted as were many capillary sized blood vessels. Mild chronic inflammation was seen. A histopathology diagnosis of BTT involving the mental branch of the trigeminal nerve was made. There was no evidence of any neurologic dysfunction 8 months after the surgery.