CT and Ultrasound Features of Basal Cell Adenoma of the Parotid Gland: A Report of 22 Cases with Pathologic Correlation

A 40-year-old woman with type 2 BCA in the left parotid gland. A and B, CT shows a round, ill-defined lesion (white arrow) with a cystic component (black arrow) in the deeper region. C, The lesion shows as heterogeneously hypoechoic, with an anechoic region (arrowheads) on sonography. The superficial border of tumor is irregular and ill defined. D, Photomicrograph (hematoxylin-eosin stain; ×50) demonstrates tumor cystic region with hemorrhage (thick arrows) and collagen deposition (thin arrow). E, Specimen histology (hematoxylin-eosin stain; ×50) shows the tumor tissue (thick arrows), the infiltration of tumor cells into the capsule (arrowhead), and tumor cells in surrounding tissue (thin arrows).

A 54-year-old woman with type 1 BCA in the left parotid gland. A, Plain CT shows a round nodule with homogeneous attenuation located at the superficial region of the superficial lobe (white arrow). B, The tumor shows slight heterogeneous enhancement with a small, low attenuation component (black arrowheads) on contrast CT. C, Sonography shows well-defined heterogeneously hypoechoic lesion. D, Correlated to the low attenuation component on the postcontrast CT, a photomicrograph of a tumor section (hematoxylin-eosin stain; ×50) shows a collagen component (thick arrows).

A 32-year-old woman with type 2 BCA in the right parotid gland. A, Plain CT shows a round lesion (9 mm) with a cystic area (black arrow) located at the deeper region of the superficial lobe. B, Contrast-enhanced CT shows obvious enhancement of the peripheral tumor rim, whereas the cystic component does not enhance. The tumor is adjacent to the retromandibular vein (black arrow). C, Sonography shows a well-defined, hypoechoic nodule with an anechoic core (white arrowheads). D, Photomicrographs (hematoxylin-eosin stain; ×50) show a hemorrhage (arrowhead) and cystic region (thick arrows) within the tumor.