Abstract
BACKGROUND: Hyalinizing clear cell carcinoma (HCCC) is an uncommon tumor that originates in the salivary glands. This neoplasia constitutes less than 1% of minor salivary gland tumors. CASE SUMMARY: A 67-year-old female visited the maxillofacial surgery department owing to a smooth, slightly yellowish protruding mass on the left side of the floor of the mouth, at the level of the molars; the tumor mass had a soft consistency on palpation and did not adhere to deep planes. The microscopical analysis of the excisional biopsy showed that the lesion was composed of sheets and cords of clear cells separated by thick eosinophilic bands of hyaline collagen. Normal glandular tissue was absent, periodic acid-Schiff with and without diastase stains, and immunohistochemical reactions were performed to confirm the diagnosis. This is the second case reported in the literature of HCCC arising in the floor of the mouth. CONCLUSION: HCCC is a rare salivary gland tumor that has not been studied extensively. Its diagnosis is usually challenging, because clinically, it can be confused with a benign neoplasm.