Extensive squamous metaplasia in minor salivary gland neoplasm mimicking squamous cell carcinoma: Diagnostic dilemma in aspiration cytology

Abstract

The surgical management of salivary gland lesions depends on cytology diagnosis, in conjunction with clinical findings and imaging studies. It is extremely important to differentiate benign and malignant salivary gland lesions preoperatively. The distinction can be challenging in aspiration cytology due to metaplastic changes, cystic changes, variable cellular components within the lesions, variants of neoplasms, and sampling issues. We are presenting the case of a 42-year-old female patient who presented with a nodular lesion in the hard palate. Fine-needle aspiration cytology of the lesion was cellular and showed sheets and singly scattered squamous cells with minimal cytological atypia. As the differential diagnosis included variety of lesions ranging from nonneoplastic lesions to benign and malignant neoplasms, surgery under frozen section control was advised. Frozen sections also showed extensive squamous areas. A minor component showing bilayered ductal pattern in a background of chondromyxoid stroma also noted. Diagnosis of a salivary gland neoplasm, possibly pleomorphic adenoma with extensive squamous metaplasia was given. Although squamous metaplasia has been reported in salivary gland neoplasms, it is extremely rare to find extensive squamous metaplasia enough to cause significant diagnostic confusion. The awareness of this extensive squamous metaplasia in benign salivary gland lesions help to distinguish it from malignant lesions and to avoid unnecessarily aggressive therapy.