Case Report: MRI, CEUS, and CT Imaging Features of Metanephric Adenoma with Histopathological Correlation and Literature Review

Abstract

The metanephric adenoma is an extremely rare, benign, embryonal-epithelial neoplasm of the kidney and has a good prognosis with appropriate treatment. It can present at any age and is often asymptomatic. Histologically, the lesion is well established; however, there have been only a few cases described with available detailed imaging findings, most of them with large renal masses typically depicted by computed tomography (CT). This case report includes imaging of contrast-enhanced MRI, contrast-enhanced ultrasound (CEUS), and CT, and thus adds to the information available, potentially promoting a nephron-sparing clinical pathway. We report on the clinical presentation, imaging, histopathological diagnosis, and treatment data of a 27-year-old female, in whom an incidental, symptomatic kidney tumor was detected. CT, CEUS, and MRI showed a suspicious unifocal renal lesion with inhomogeneous enhancement, which was indistinguishable from renal cell carcinoma. After laparoscopic resection, a metanephric adenoma with microscopically partially glandular, partially nest-like solid growth and without distinctive atypia was diagnosed pathohistologically. Immunohistochemistry results were positive for Wilms Tumor 1 and CD57 and negative for EMA and CK7: 2–3% positive cells in MIB1 coloring. At 3-month and 1-year follow-up, the patient was asymptomatic and imaging showed no recurrence of renal masses or metastases.

Metanephric adenoma managed with robotic partial nephrectomy: A case report

“…On magnetic resonance imaging (MRI), MAs have exhibited hypointense characteristics on T1-weighted imaging and either iso-or slightly hyperintense features on T2-weighted imaging [17]. In a review of 8 cases, Yan et al reported the MAs appeared isointense on both T1-and T2-weighted imaging [12].…”

Renal Mass Found on Imaging of Spine for Back Pain: An Incidental Finding

“…A metanephric adenoma is more common in females. Most of the tumors present as unilateral and unifocal, circumscribed but not encapsulated lesions [1].…”