SYNCHRONOUS MALIGNANT GRANULAR CELL TUMORS OF THE RIGHT RETROMOLAR TRIGONE AND LEFT PAROTID GLAND: A CASE REPORT

Abstract

<h3>Introduction</h3> Granular cell tumors (GCTs) are uncommon, benign mesenchymal neoplasms of Schwann cell origin. In the head and neck, the tongue is the most common site. Malignant tumors comprise about 2% of all granular cell tumors. Herein, we report a case of a malignant granular cell tumor (MGCT) in the right retromolar trigone and a synchronous tumor in the left parotid gland. The literature suggests that this may be the second case of a malignant granular cell tumor described in the oral cavity. <h3>Case Report</h3> A 51-year-old male patient presented to the otorhinolaryngology clinic for a progressively enlarging right retromolar trigone lesion, extending to the buccal mucosa and floor of mouth and posteriorly to the tonsil. Extraorally a left parotid swelling, right-sided lymphadenopathy, and cranial nerve fallout of V1, V2, III, and VI were noted. Computed tomography showed a homogeneously enhancing soft tissue mass in the right oral cavity extending intracranially, as well as a mass in the left parotid. Histopathologic examination revealed synchronous MGCTs. The tumors were deemed inoperable and the patient was offered palliative radiotherapy. <h3>Discussion</h3> MGCTs are rare high-grade malignant mesenchymal tumors representing only 1% to 2% of all GCTs. MGCTs commonly affect the thigh, extremities, and trunk, and involvement of the oral cavity is rare. The prognosis is poor, with a 39% mortality rate in 3 years. <h3>Conclusions</h3> Although malignant granular cell tumors are rare, clinicians and histopathologists must be familiar with this entity. However, distinction between benign and malignant tumors can be difficult owing to striking histologic similarities.