Hyalinizing clear cell carcinoma-a rare entity in the oral cavity: A case report

Figure 1 Clinical and macroscopic aspects of the lesion. A: Volume increase in floor of mouth on the left side, measuring approximately 5 cm × 4 cm × 4 cm, with smooth, flat surface on palpation, not adherent to deep planes; B: Macroscopic appearance of the specimen by excisional biopsy.

Figure 2 Histological characteristics of the tumor. A and B: Groups of clear cells separated by thick bundles of eosinophilic collagen fibers with hyaline appearance; C: Neural invasion area; D: Diffuse proliferation of tumor cells forming solid areas or tumor sheets. A population of tumor cells with eosinophilic cytoplasm was also observed (Hematoxylin and eosin, original magnification A: ×100, B: ×200, C, D: ×400).

Figure 3 Negative tumor cells staining and histochemistry periodic acid-Schiff positive without diastase. A: Negative tumor cells staining by periodic acid-Schiff with diastase; B: Histochemistry periodic acid-Schiff positive without diastase (original magnification, ×400).

Figure 4 Immunohistochemical profile of the tumor. An intense and diffuse positive reaction was observed in most tumor cells for AE1-AE3 (A), CK7 (C), and p63 (D), whereas CK5 (B) showed focal positivity (original magnification A, B, C, D. ×200).