2022 Volume 61 Issue 6 Pages 431-437
Background : Intraductal carcinoma (IDC) is a rare salivary gland tumor with a good prognosis.
Case : The patient was a man in his seventies who presented to us with a 10-year history of a small left parotid mass that had started to increase in size approximately one year ago. MRI revealed a 50-mm multilocular cystic mass caudally over the inferior pole of the left parotid gland, and fine-needle aspiration cytology (FNAC) was performed. The FNAC specimen revealed a mildly overlapping epithelial mass in a background of lymphocytes, neutrophils, and macrophages phagocytosing hemosiderin. The nuclei of the tumor cells were relatively small and mildly atypical, with granular chromatin and one or two small nucleoli. The tumor cells contained greenish and vacuolated cytoplasm and intracytoplasmic lumina containing secretions as well as brownish-red granules. Since the cytological findings suggested a low-grade malignant lesion, we categorized the findings as “suspicion for malignancy, low grade” according to The Milan System for Reporting Salivary Gland Cytopathology, with the differential diagnosis including secretory carcinoma and low-grade adenocarcinoma (cystadenocarcinoma).
Conclusion : IDC may be cytologically similar to secretory carcinoma and low-grade adenocarcinoma (cystadenocarcinoma), which may pose difficulties in accurate estimation of the histological type. However, since IDC has a more favorable prognosis than other malignant salivary gland tumors, it is important to confirm the low-grade malignant nature of the tumor by FNA before surgery.
