Case #46 Discussion

Summary: The patient complains of a painful enlargement of three weeks duration that is increasing in size and bleeds if the patient bites it.  The lesion is a localized but not well-circumscribed, 2 cm in diameter enlargement that is present in the left posterior buccal mucosa.  The lesion is firm, tender to palpation, has a smooth surface, does not blanch, and is fixed to surface mucosa and underlying structures.  Paresthesia is present in the distribution of the long buccal nerve. Lesions to Exclude from the Differential Diagnosis: The lesion is described as an exophytic, soft tissue enlargement.  Reactive soft tissue enlargements may be excluded from the differential diagnosis because the lesion is persistent and progressive. Within the category of tumors, benign tumors and soft tissue cysts can be excluded  because the lesion in this case is rapidly growing, fixed to surrounding structures, painful and is causing paresthesia. From the category of malignant tumors, squamous cell carcinoma can be excluded because it develops from the surface epithelium, while the surface of the lesion in this case is normal.  Carcinoma arising in pleomorphic adenoma can be excluded because these occur in pre-existing benign pleomorphic adenomas of long duration.  Lesions to Include in the Differential Diagnosis: Salivary gland adenocarcinoma, lymphoma, and sarcoma should be included in the differential diagnosis because they are malignancies involving subepithelial tissue and they sometimes demonstrate a normal overlying surface, as in this case.  Adenoid cystic carcinoma, acinic cell adenocarcinoma, high-grade mucoepidermoid carcinoma, and high-grade salivary gland adenocarcinoma, not otherwise specified can present as rapidly growing lesions. Initial Management: The patient requires an incisional biopsy for definitive microscopic diagnosis and also further local and systemic evaluation by an oncologist.  Final Diagnosis: High-grade salivary gland adenocarcinoma, not otherwise specified. Further Management and Prognosis: The prognosis depends upon the extent of local tumor invasion and the presence of metastases.  Treatment would involve surgery, radiation therapy, chemotherapy, or a combination of these modalities.