Advanced Wilms Tumor in a Middle-Aged Adult: A Case Report.

Wilms tumor, or nephroblastoma, is a malignant embryonal tumor originating from nephrogenic blastema, which imitates the histology of a developing kidney. Primarily, it occurs in children. Wilms tumor is exceedingly rare in adults, where the diagnosis is often delayed, and the prognosis tends to be worse compared to children. Owing to their rarity in the adult population, Wilms tumors do not have true treatment guidelines and are instead treated with regimens identical to those for pediatric tumors. Herein, we present a case of Wilms tumor in a middle-aged adult and review the relevant literature. A 48-year-old female presented to our facility with a long-standing history of left flank pain for more than 4 months. Upon examination, a huge palpable mass in the left lumbar region was noted. An abdominal-pelvic CT scan revealed a large, complex, heterogeneous, enhancing cortical renal mass with cystic and solid components. The mass had an exophytic growth, surrounded by fat tissue, occupying the lower pole of the left kidney, compressing renal parenchyma with no infiltration of the renal vein or inferior vena cava. A clinical diagnosis of renal cell carcinoma was considered, and surgery was recommended. Pathology evaluation of the nephrectomy specimen confirmed it to be a Wilms tumor. She was discussed in a multidisciplinary team, and a consensual decision was made to be given palliative chemotherapy with a combination of vincristine, dactinomycin, doxorubicin, and cyclophosphamide after optimization. This case report highlights the rarity of Wilms tumor in adults, especially in middle age, and emphasizes the importance of considering it in the differential diagnosis of renal masses.