Oral adenoid squemous carcinoma. Tumor markers and prognosis

CASE REPORT: A 58-year-old female patient presented with an exophytic adenoid squamous cell carcinoma on the right alveolar process of the lower jaw. Histological and immunohistochemical differential diagnosis and cellular background of the unfavorable prognosis are described. The patient was treated with curative intent by radical tumor resection including partial mandibulectomy, extensive conservative/radical neck dissection, and postoperative radiation. The adenoid squamous cell carcinoma was classified as pT4, pN0, cM0, R0. During radiation, regional lymph node metastases and distant metastases developed. The patient died of distant metastases 7 months after the initial diagnosis. HISTOPATHOLOGIC FINDINGS: Tumor cells of adenoid squamous cell carcinoma express epithelial intermediate filament cytokeratin, epithelial membrane antigen (EMA), and epithelial basal membrane protein laminin-5 (Ln-5). Glandular differentiation can be excluded by the absence of epithelial mucins (Alcian blue, mucicarmine). Differentiation from angiosarcoma can be performed using endothelial differential markers CD31, CD34, and factor VIII-associated antigen (FVIII-ass. AG). Both entities are characterized by high proliferation and Ki-67 index of 20%. beta-catenin (cell-cell adhesive protein) loses its primary membrane-bound localization and can explain the histologic pattern of acantholysis. Ln-5 (guide rail of invasion) is massively expressed in adenoid squamous cell carcinoma cells and may be responsible for rapid progression. CONCLUSIONS: Pseudopapillary proliferation, cellular atypia, vascular-like cavities, expression of cytokeratin, EMA, and Ln-5 are common features of oral adenoid squamous cell carcinoma and angiosarcoma. Diagnosis is determined by the absence of endothelial differential markers CD31, CD34, and FVIII-ass. AG. Modulation of the beta-catenin pattern (transcription factor of Ln-5) and massive expression of invasion factor Ln-5 are suggested as cell biological reasons for rapid progression of adenoid squamous cell carcinoma.