2025 Volume 24 Issue 2 Pages 204-210
A 63-year-old woman presented with a gradually enlarging, hard, subcutaneous tumor in the left preauricular area that had been present for nine months. Magnetic resonance imaging revealed a tumor in the left parotid gland. A punch biopsy was unable to reach the deeply situated tumor, preventing a definitive diagnosis from being made. The tumor, a well-demarcated encapsulated mass, was completely excised from the superficial lobe of the parotid gland. Pathological examination revealed that the tumor was primarily composed of tubular and bilayer glandular structures, with some cribriform structures and perineural infiltration. Immunohistochemical staining revealed that the inner cells were positive for epithelial membrane antigen and C-kit, whereas the outer cells were positive for α-smooth muscle actin and calponin. The Ki-67 labeling index was ＞20%. MYB gene rearrangement was observed. These clinical and pathological findings led to a diagnosis of salivary adenoid cystic carcinoma (ACC), a relatively rare malignant tumor. Unlike its cutaneous counterpart, primary salivary ACC generally has a poor prognosis. Long-term follow-up of patients with salivary ACC is required to monitor for tumor recurrence. Skin Research, 24 : 204-210, 2025
