Diagnostic Pitfalls in Salivary Gland Tumours: A Case Series

Abstract

Introduction:
Salivary gland tumours are rare and heterogeneous neoplasms, accounting for 3–6% of head and neck tumours. Pleomorphic adenoma (PA) is the most common benign tumour and is often suspected clinically because of its typical presentation as a painless, slow-growing swelling. However, several other entities may mimic PA, creating diagnostic challenges.

Case Presentation:
This case series includes four patients presenting with painless, slow-growing salivary gland swellings: case 1 of the parotid gland, case 2 of the submandibular gland, case 3 of the sublingual gland, and case 4 of the parotid gland, with clinical and imaging features suggestive of pleomorphic adenoma. All patients underwent radiological evaluation, fine-needle aspiration cytology (FNAC), and definitive surgical excision. Cytological interpretation was performed using the Milan System for Reporting Salivary Gland Cytopathology, which gave us the mirage of pleomorphic adenoma in case 1 and salivary gland neoplasm of unknown potential(SUMP) in the remaining three cases, but histopathologically all the four cases were reported differently as case 1 as myoepithelioma, case 2 and 3 as Adenoid cystic carcinoma(AdCC) whose grading was assessed using the MD Anderson grading system and case 4 as Basal cell adenoma.

Conclusion:
This case series emphasises the diagnostic overlap between pleomorphic adenoma and other salivary gland tumours such as AdCC and myoepithelioma. FNAC and imaging have limitations in distinguishing these entities, and histopathology remains the gold standard for accurate diagnosis and management. Awareness of this overlap is crucial, particularly in submandibular and sublingual gland tumours, where the probability of malignancy is higher.