Hyalinizing clear cell carcinoma arising on the anterior palatoglossal arch.

Hyalinizing clear cell carcinoma (HCCC) is very rare in the oral cavity, arising more frequently in the minor salivary glands. We present the case of a 57-year-old woman with a swelling on the anterior palatoglossal arch of 2x1 cm size. An incisional biopsy was taken and histological examination revealed typical clear cells arranged in anastomosing trabeculae, cords, nests, and solid sheets with a hyalinizing stroma. These clear cells were strongly positive to periodic acid-Schiff stain (PAS) but were negative for mucicarmine. Immunohistochemically, the neoplastic cells were immunoreactive to pancytokeratin, focally positive to EMA, but negative for smooth muscle actin (SMA), vimentin and S-100 protein, HMB45, CD68, carcinoembryonic antigen (CEA) and glial fibrillary acid protein (GFAP). These findings allowed us to define this tumor as a clear cell tumor of the anterior palatoglossal arch. The tumor was subjected to radical excision and the patient is doing well at twelve months after surgery. This report focuses on the heterogeneous group of clear cell neoplasms with the intent of pointing out some aspects that may contribute to forming a diagnosis of HCCC, and which, above all enable us to distinguish this neoplasm from other very similar forms occurring in the oral cavity

Nevus of Hoffmann-Zurhelle: a case around the right parotid duct.

Nevus lipomatosus cutaneous superficialis (NLCS) is an extremely rare hamartomatous disorder comprising of ectopic mature adipose tissue. The lesions take the form of large, slow-growing, sessile or pedunculated tumors. We report the case of an 11-year-old boy with NLCS, dating back many months, that was growing as a cuff around the parotid duct. The lesion was successfully removed by diode laser excision (980 nm) and a diagnosis of NLCS was rendered. At one-year follow-up the tumor has not recurred. To our knowledge this is the first report of NLCS in the oral cavity; the characteristic clinical and morphological features aided in the diagnosis of this hamartoma. The peculiarity of this case is its location; the extreme rarity of NLCS, in general, probably makes this case unique

Adenomatoid odontogenic tumor: a case report with immunohistological profile.

The adenomatoid odontogenic tumor (AOT) is an uncommon tumor of odontogenic origin, composed of odontogenic epithelium and characterized by slow but progressive growth. We report a rare case of AOT in an 18-year-old, who presented with a palpable bony-hard swelling in the anterior maxillary region. The tumor was radiographically well-defined, and exhibited unilocular radiolucency. Histologically, the appearance was of solid nodules of cuboid or columnar cells of odontogenic epithelium, forming typical nests or duct-like structures. Immunohistochemistry was positive for cytokeratins (CK) CK5/6, CK17, CK19 and negative for KI-67. The results were consistent with a diagnosis of AOT. CONCLUSION: A case of AOT is presented, emphasizing on the importance of recognizing neoplasms arising in odontogenic tissues. Recurrences seldom occur, and surgical cure is recommended