Hyalinizing clear cell carcinoma: a case report and review of the literature

Hyalinizing clear cell carcinoma (HCCC) is a low-grade malignancy with infiltrative growth pattern. It affects mainly the minor salivary glands of adult women. The most frequent locations of this tumor are the palate and tongue. HCCC shows a poorly circumscribed, infiltrative, and essentially monomorphic population of clear cells with few mitoses and almost no nuclear or cellular pleomorphism. These cells form trabeculae, cords, islands, and/or nests, circumscribed by variable amounts of hyalinized fibrous bands with foci of myxohyaline stroma. S-100 protein, muscle-specific actin, smooth muscle actin, myosin, and calponin are consistently negative, which strongly indicates the absence of myoepithelial cell differentiation in this tumor. We present a case of HCCC affecting the upper vestibule in a 53-year-old man. The patient was treated by surgery and postoperative radiation and did not show recurrence or distant metastases 3 years after treatment. Discussed also are the clinical and pathologic features of this tumor along with the differential diagnosis and a literature review.