Tie-Jun Li

Clear Cell Odontogenic Carcinoma A Clinicopathologic and Immunocytochemical Study of 5 Cases

CONTEXT Odontogenic tumor composed predominantly of clear cells is a rare neoplasm of the jaws that was initially designated as clear cell odontogenic tumor. Subsequent reports in the literature, however, all have indicated that this tumor exhibits an aggressive behavior characterized by infiltrative local growth, recurrence, or metastases. OBJECTIVE To ascertain the clinicomorphologic features and biologic behavior of this tumor group, we present 5 additional cases using the term clear cell odontogenic carcinoma. DESIGN Histologic and immunohistochemical examinations were performed on clear cell odontogenic carcinomas from 5 patients. Clinical and follow-up data were recorded, and the literature was reviewed. RESULTS The patients were 1 man and 4 women with an average age of 42.4 years at diagnosis. Three tumors occurred in the mandible and the other 2 in the maxilla. Four of the 5 cases occurred in the anterior or premolar areas of the jaws, appearing as poorly marginated radiolucencies. All cases consisted of islands and sheets of large clear cells and small basaloid cells with scanty eosinophilic cytoplasm, which were separated by thin, mature, fibrous septae. The tumors were unencapsulated and showed aggressive infiltration of the surrounding muscle and perineural tissues. Most of the clear cells contained cytoplasmic glycogen. Immunocytochemically, the tumor cells were positive for pan-keratin, cytokeratin 19, and epithelial membrane antigen, but were negative for vimentin, S100 protein, desmin, smooth muscle actin, human melanoma antigen (HMB-45), and alpha(1)-antichymotrypsin. Follow-up data showed 4 of 5 patients to have multiple local recurrences, and 1 of these 4 had submandibular lymph node metastasis and a fatal outcome due to uncontrollable tumor growth. CONCLUSION These results suggest that odontogenic clear cell neoplasms are at least low-grade malignancies and should be classified as carcinomas.

Differences in collagen fibres in the capsule walls of parakeratinized and orthokeratinized odontogenic cysts

Epithelial-mesenchymal interactions are thought to play an important role in the pathogenesis of odontogenic lesions. Keratocystic odontogenic tumour (KCOT) is a benign cystic neoplasm with a characteristic parakeratinized epithelial lining, which differs histologically and behaviourally from the so-called orthokeratinized odontogenic cyst (OOC). The purpose of this study was to investigate the differences in collagen fibres within the fibrous tissue walls of KCOT and OOC. Formalin-fixed paraffin-embedded tissue samples from 15 cases of KCOT and 15 cases of OOC were collected. Paraffin sections were stained with picrosirius red and observed under a standard light microscope using optical polarization. Unicystic ameloblastoma (UA, 15 cases) and subcutaneous epidermoid cysts (EC, 15 cases) were included in the study for comparative purposes. Significant difference was detected between the polarization colours in the fibrous tissue walls of KCOT and OOC (P<0.05), whilst no significant differences were found between KCOT and UA and between OOC and EC (P>0.05). The stromal collagen fibres of KCOT were different from those of OOC, but similar to those of UA, which suggests that the stroma of KOCT may play an important role in determining the neoplastic behaviour of the lesion through epithelial-mesenchymal interaction.

Ossifying Fibromyxoid tumor of soft parts in head and neck: case report and literature review

BackgroundOssifying fibromyxoid tumor of soft parts (OFMT), is a rare but morphologically distinctive neoplasm of uncertain histogenesis that most frequently affects middle-aged male adults. Clinically, it usually presents as a slowly enlarging, small, circumscribed mass, which in most cases is painless. OFMT is most frequently found within the subcutaneous tissues of extremities or trunk, and rarely in the oral/head and neck region. We present an unusual case of this tumor in the submandibular region, and, based on the current medical literatures this is probably the first case described in this anatomical location.Case presentationA 32-year-old male presented to our outpatient clinic with a right submandibular mass with 1-year of evolution. Excisional biopsy showed that it was characterized by ossification along the periphery of the lesion. The neoplastic cells were spindle-like with scant eosinophilic cytoplasm. These cells were arranged with uniform cell-to-cell space in a fibromyxoid stroma. Small and large clusters of calcifications were present within the tumor. Immunohistochemically, the case showed positive staining of S-100 protein, vimentin, nestin, calponin, SMA, GFAF, desmin, INI-1, caldesmon, and CD34. It also showed negative staining of CK, CK7, CK8/18, NF, and EMA. About 2% of neoplastic cells showed positive staining of Ki67. Based on these features, the final pathological diagnosis was OFMT.ConclusionsIt is hoped that a greater understanding of OFMT in the head and neck region will avoid potential misdiagnosis, and contribute to determining the correct management, which appears to be complete surgical excision with close follow-up for recurrence surveillance.