BACKGROUND: Tubular papillary adenoma is a rare eccrine-derivate dermal adnexal tumor, located in the scalp mostly. Earlier, the sebaceous cyst size was larger than 5 cm in diameter and may be confused with subcutaneous tumor. Cases of the tumor on the buttock with rapid growth are rare, therefore magnetic resonance imaging (MRI) may be helpful to determine their precise size, nature, and invasion of nearby organs for further confirmation.

CASE REPORT: We report on a case of a 35-year-old male with a rapid-growth tumor on the buttock. Initially, he had received drainage by syringe and the amount of drainage was 50 mL. MRI favored diagnosis of sebaceous cyst. As for recurrent tumor, the pathology revealed tubular papillary adenoma.

CONCLUSIONS: MRI might play an important role on imaging of soft tissue to exclude some uncertain malignant tumors. This case report indicated a rare case of a large rapid-growing tubular papillary adenoma on the buttock that required further management.

Keywords: Buttocks, Magnetic Resonance Imaging, Neoplasms, Adnexal and Skin Appendage, Sweat Gland Neoplasms, Tubular Sweat Gland Adenomas