Ultrasonographic Features of Eccrine Spiradenoma

The purpose of this series was to evaluate the features of eccrine spiradenoma on ultrasonography (US). We reviewed the clinical data of 8 patients with eccrine spiradenoma who underwent preoperative US at 4 different medical institutions from 2004 to 2016 and analyzed the US features in terms of the tumor location, size, shape, margin, echo texture, echogenicity, posterior acoustic enhancement, calcification, septum, and color Doppler flow. There were 7 female patients and 1 male patient. The mean patient age was 45.6 years (range, 28-60 years). Most of the tumors were located primarily in the subcutaneous fat layer. The mean size of the tumors was 14.3 mm. The masses had a lobular appearance in 7 patients and had a tractlike structure in 3 patients. In 6 patients, the masses had a heterogeneous echo texture. Six cases showed hypoechogenicity with more hypoechoic foci in the masses, and 2 cases showed hypoechogenicity only. Color Doppler flow was evaluated in 7 patients; the blood flow was central and peripheral in 4 patients and only peripheral in 3 patients. All cases showed posterior acoustic enhancement and had well-defined margins. Calcification and septa were not seen in any cases. Eccrine spiradenoma is usually located in the subcutaneous fat layer, has a well-defined margin, a lobulated appearance, occasionally with a tractlike structure, a heterogeneous echo texture, a hypoechoic appearance with internal hypoechoic foci and posterior acoustic enhancement, and shows blood flow in the peripheral portion, with or without blood flow in the central portion.