Adenosquamous carcinoma is a very rare tumor that is characterized pathologically by the simultaneous presence of distinct areas of adenocarcinoma and squamous cell carcinoma. Only 15 cases in the oral cavity are reported in the literature, most occurring in middle-aged and elderly males. Pain is a commonly reported presenting symptom and may be related to the frequent presence of perineural invasion. Most cases have been treated surgically. However, early recurrence and death due to disease are common. We report an exceptional case occurring in a 22-year-old female. The tumor was associated with dysplasia of both minor salivary gland ductal epithelium and surface mucosal epithelium. Perineural invasion was also present. The patient was treated with combined surgery and radiotherapy and remained well for 9 months before developing locoregional recurrence and ultimately succumbing to the disease.