Adenoid squamous cell carcinoma is an uncommon variant of squamous cell carcinoma (SCC) that is characterized by a mixture of squamous components with adenocarcinomatous elements in the tumor. A rare case of this tumor occurring in the maxillary sinus is reported.
A 53-year-old man in whom a poorly-differentiated SCC of the right maxillary sinus (T 4 N 0 M 0) was initially diagnosed by biopsy was admitted to the Hyogo College of Medicine Hospital. The serum levels of SCC-related antigen (SCC-Ag) and carcinoembryonic antigen (CEA) in the serum of the patient before treatment were high, being 52.0ng/ml and 25.0ng/ml, respectively. A reduction in tumor volume by radiotherapy, intra-arterial 5-FU infusion and necrotomy resulted in a marked decrease in serum levels of SCC-Ag and CEA. However, both tumor markers increased with tumor regrowth. Furthermore, tumor specimens, obtained by necrotomy and tumor reduction operation, were histologically diagnosed as adenoid squamous cell carcinoma, suggesting modification by cancer therapy. Immunohistochemical study using the ABC method revealed weak staining of SCC-Ag in the cytoplasm and strong staining of CEA in the plasma membrane of tumor cells. The patient died of intracranial invasion 2 years after combined therapy.