2021 Volume 60 Issue 1 Pages 33-37
Background : Adenoid cystic carcinoma (AdCC) is the most commonly encountered malignant tumor of the minor salivary glands. Herein, we report a case of AdCC, in which differential diagnosis from a basaloid-like tumor was achieved by liquid-based cytology (LBC) of oral brushings.
Case : A male patient in his 60's was referred to our hospital by his family dentist. A tumor was identified by endoscopy in the upper right palate, and oral brushing LBC was performed, which showed clusters of small round cells with basaloid features. However, the presence of tumor clusters consisting of monotonous cells led to the suspicion of AdCC, and immunocytochemistry was performed. The tumor cell nuclei showed strongly positive staining for MYB protein, and we made the diagnosis of AdCC. Biopsy revealed nests and sheets of small round, basaloid cells, and identifiable atypical double-layered ductal structures in the solid nests which were predominant. The tumor cells showed strongly positive staining for MYB. FISH analysis revealed MYB split signals (68%) in the tumor cells. Based on these findings, the patient was diagnosed as having AdCC.
Conclusion : Although differential diagnosis from a basaloid-like tumor was required in this case, histological diagnosis of AdCC was possible by comprehensive analysis of the clinical information, cytological findings and results of MYB staining.
