LONG-STANDING PLEOMORPHIC ADENOMA OF MINOR SALIVARY GLANDS: A CASE STUDY WITH UNUSUAL HISTOLOGICAL FEATURES

*Dr. Magesh Karuppur Thiagarajan, M.D.S., Ph.D., Dr. Swaathi Ravindran, M.D.S., Dr. Vivek N, M.D.S., Dr. Aravindhan Ravi, M.D.S., Dr. Sathya Kumar Mayilvakanam, M.D.S., Dr. Sivachandran Annamalai, M.D.S.

Pleomorphic adenoma, the most common benign salivary gland neoplasm, presents a unique case when located in the hard palate, a rare site for this tumor. We report a case of a 34-year-old male with a 13-year history of a slowly growing, asymptomatic swelling in the right hard palate. Clinical examination revealed a 5x4 cm, non-fluctuant, non-pulsatile, firm mass extending from the rugae to the soft palate, crossing the midline. Radiographic imaging showed no bony erosion. Fine-needle aspiration cytology suggested pleomorphic adenoma, which was confirmed by histopathological analysis after total excision. The tumor was well-encapsulated, composed of epithelial and myoepithelial elements in a myxoid stromal background. Numerous duct-like structures with eosinophilic secretions were identified. Notably, the tumor exhibited prominent squamous metaplasia with keratin pearl formation and extensive keratin cyst formation, which are rare histological features that can mimic malignancy. The absence of cytological atypia, abnormal mitoses, and invasive patterns confirmed the benign nature of the lesion. This case highlights the importance of considering pleomorphic adenoma in the differential diagnosis of palatal swellings and emphasizes the role of comprehensive clinical, radiographic, cytological, and histopathological evaluation in accurately diagnosing and managing these tumors, particularly when unusual histological features are present.