Hyalinizing Clear Cell Carcinoma of Palate: A Systematic Review

Abstract

Hyalinising clear cell carcinoma (HCCC) is a rare, low-grade malignant tumour of minor salivary gland origin that most commonly affects the palate. This systematic review analysed the demographic profile, clinical presentation, diagnostic features, management, and outcomes of reported HCCC cases. A comprehensive review of English-language studies published between 2000 and 2025 was conducted, with most included studies comprising case reports and small case series. The findings indicated that HCCC predominantly affects middle-aged individuals, particularly those aged 40–60 years, with a slight female predominance. Clinically, it typically presents as a slow-growing, painless palatal swelling that often mimics benign salivary gland tumours. The hard and soft palate were the most commonly involved sites. Radiographic features were variable and non-specific, ranging from well-defined soft-tissue masses to lesions with bone erosion and involvement of adjacent structures. Histopathological examination consistently demonstrated nests and cords of clear epithelial cells within a hyalinised fibrous stroma and an infiltrative growth pattern. Immunohistochemistry was essential for diagnosis, with tumours showing positivity for cytokeratin, p63, EMA, and PAS and negativity for markers such as S100 and SMA. In some cases, EWSR1-ATF1 gene fusion supported the diagnosis. Differential diagnoses included other clear cell neoplasms, particularly metastatic renal cell carcinoma and salivary gland tumours. The mainstay of treatment was wide surgical excision with clear margins, with adjuvant radiotherapy reserved for selected cases. Most patients had favourable outcomes with low recurrence rates, although occasional local recurrence was reported. Overall, HCCC demonstrates indolent behaviour and a good prognosis when diagnosed early and treated appropriately. Regular follow-up is recommended to monitor for recurrence.