Oral squamous cell carcinoma with prominent clear-cell features: a case report and diagnostic review

Abstract

Clear-cell variants of oral squamous cell carcinoma (OSCC) are exceedingly rare and present a diagnostic challenge due to their uncommon histomorphological features and overlap with other clear-cell neoplasms. We report a case of a 65-year-old male presenting with a persistent ulceroproliferative lesion in the lateral oropharyngeal wall. Histopathological examination revealed nests of squamous epithelial cells with abundant clear cytoplasm and marked pleomorphism. Periodic acid–Schiff with diastase (PAS-D) staining indicated glycogen accumulation, and immunohistochemistry confirmed epithelial origin via strong pan-cytokeratin expression. These findings supported the diagnosis of the clear-cell variant of OSCC. The differential diagnosis encompassed salivary gland tumors, odontogenic lesions, and metastatic clear-cell malignancies. Accurate identification required a combination of histological, histochemical, and immunohistochemical analyses. Although the World Health Organization has not yet classified this variant formally, its recognition is crucial due to the possibility of a more aggressive clinical course. This case contributes to the limited literature and underscores the importance of comprehensive diagnostic approaches to improve our understanding of this rare entity.