Case #42 Discussion

Summary: The patient complains of a soft tissue enlargement that is progressively increasing in size, located on the right posterior hard palate of one-and-a-half years duration.  The patient has a maxillary denture which she wears 24 hours a day.  The lesion is nonpainful, does not bleed, and is irritated by her denture only when she eats.  The lesion is a firm, nontender, well-circumscribed, exophytic, 1 x 1 cm soft tissue enlargement that is fixed to the surface mucosa and underlying structures.  The surface is smooth to palpation, mildly erythematous due to denture trauma, and does not blanch.  A panoramic radiograph reveals no evidence of underlying bony abnormality.  Lymphadenopathy is not present.   Lesions to Exclude from the Differential Diagnosis: The lesion is described as a soft tissue enlargement.    Reactive soft tissue enlargements can be excluded because the lesion in this case is persistent, progressive, nonpainful, and slowly growing.  In addition, the lesion appears to be displacing the denture, rather than the lesion being the result of irritation from the denture. Within the category of tumors, high-grade malignant tumors are excluded because the lesion in this case is well-circumscribed, slowly growing, nonpainful, not ulcerated, and has not destroyed underlying bone.  Soft tissue cysts may be excluded from the differential diagnosis because cysts are compressible, and the lesion in this case is firm to palpation.  Within the category of benign tumors, epithelial lesions may be eliminated because the lesion is described as having a smooth surface rather than a yellow or white, rough surface.  From the category of benign and low-grade malignant salivary gland tumors, papillary cystadenoma lymphomatosum can be excluded because it is found almost exclusively in the major salivary glands, especially the parotid gland.  From the category of benign mesenchymal tumors, epulis fissuratum, peripheral ossifying fibroma, peripheral giant cell granuloma, and congenital epulis can be excluded based on location.  In addition, peripheral giant cell granulomas are vascular and typically blanch.  Rhabdomyoma can be excluded because skeletal muscle is not present on the hard palate.  Hemangioma, lymphangioma, pyogenic granuloma, and lipoma can be excluded because they are compressible to palpation. Also, hemangioma and pyogenic granuloma are vascular lesions and will blanch on pressure.  Neuroma can be excluded because it is typically painful to palpation.    Lesions to Include in the Differential Diagnosis: Thus, the differential diagnosis includes: irritation fibroma, leiomyoma, neurofibroma, schwannoma, granular cell tumor, pleomorphic adenoma, monomorphic adenoma, adenoid cystic carcinoma, acinic cell carcinoma, and polymorphous low-grade adenocarcinoma.  Note the broad differential diagnosis for a localized, slowly growing soft tissue enlargement of the posterior hard palate. Management: The correct management for this lesion is excisional biopsy, or incisional biopsy followed by complete excision. Final Diagnosis: The microscopic diagnosis of this lesion was pleomorphic adenoma (mixed tumor).  The prognosis is good with excisional biopsy.  The patient should be followed for the possibility of recurrence.