Diagnostic Approaches to Adult Cystic Nephroma: Insights From Two Cases.

BACKGROUND Adult cystic nephroma is a rare benign renal tumor within the mixed epithelial and stromal tumor family. It is unilateral and characterized by a cystic structure without evidence of a solid component; it predominantly affects middle-aged women. Immunohistochemical testing is a rapid and reliable diagnostic method that assists with differential diagnosis from other benign and malignant renal tumors. CASE REPORT We present 2 cases of cystic renal tumors, 1 of which was diagnosed outside the peak incidence age range. Clinical presentations included abdominal pain, an abdominal mass, and hematuria. Paraclinical investigations yielded normal results; however, computed tomography identified a cystic renal lesion involving either two-thirds of the kidney or the central portion in contact with the compressed renal hilum in both cases. Surgical treatment consisted of total nephrectomy; the definitive diagnosis was established after histopathologic and immunohistochemical evaluation. Postoperative recovery was favorable, without immediate or long-term complications at 6 months after surgery. CONCLUSIONS Adult cystic nephroma is a benign tumor with nonspecific clinical manifestations and imaging characteristics, making differentiation from other cystic renal tumors challenging. In such cases, there is a risk of excessive therapeutic interventions, including surgery and unnecessary medical treatment (eg, antiparasitic therapy), particularly among patients who exhibit rare conditions with overlapping radiologic features.