Salivary adenoid cystic carcinoma with an early phase of high-grade transformation: case report with an immunohistochemical analysis

BACKGROUND: The early phase of salivary gland carcinomas with high-grade transformation (HGT) is extremely rare. We reported one case of adenoid cystic carcinoma (AdCC) with early HGT, herein. CASE PRESENTATION: The patient was a 27-year-old Japanese woman who suffered from swelling of the left parotid region. Most of this tumor consisted of typical AdCC histology, whereas the central area of this tumor was composed of solid growth component by atypical cells with clear cytoplasm and marked nuclear atypia. Immunohistochemically, this area was strongly and diffusely positive for epithelial membrane antigen, p53, p16, Her-2, cyclin A and cyclin B1. The Ki-67 labeling index of this area was high, entirely different from that of AdCC area. CONCLUSION: Overall, this area was an early phase of AdCC-HGT. This case is the second case of early AdCC-HGT. We discuss the development of salivary gland carcinoma with HGT. VIRTUAL SLIDES: http://www.diagnosticpatology.diagnomx.eu/vx/1598278104895730