Primary Adenocarcinoma of the Upper Urinary Tract: A Systematic Review of the Literature on a Rare Entity

Background: Only a few published cases of primary adenocarcinoma of the upper urinary tract have been described in the literature. The aim of this systematic review was to collect all published cases of primary adenocarcinoma of the upper UT and identify prognostic factors and useful diagnostic modalities for their optimal treatment. Methods: Systematic research in the PubMed/Medline and Scopus databases concerning primary adenocarcinoma of the upper urinary tract was performed by two independent investigators. A total of 85 studies were included in the review. Results: In total, 84 patients were included, consisting of 54 males (64.29%) and 30 females (35.71%). Out of the available data, 24.71% reported a history of lithiasis, 16.47% episodes of pyelonephritis and 10.59% a history of hydronephrosis. Concerning histologic findings on excised tumors, 52.44% of neoplasms were mucinous, 19.51% tubulovilous, 18.29% papillary, 4.88% mixed mucinous-papillary and 4.88% poorly differentiated. Concerning anatomical origin, 62.34% of tumors were found in the renal pelvis, 22.08% in the ureter and 12.99% in both the renal pelvis and the ureter. Surgical treatment was the preferred therapeutic option and was performed in 96.39% of the included patients. In multivariable analysis, a statistically significant relationship was found between a clinical cure and ureter origin of the lesion (OR: 0.17, 95% CI: 0.00-0.22, p = 0.002), the presence of an abdominal mass (OR: 0.08, 95% CI: 0.01-0.63, p: 0.034) and a poorly differentiated histological type (OR: 0.02, 95% CI: 0.00-0.91). In multivariable time-to-event analysis, the male sex (HR: 0.12, 95% CI: 0.02-1.01, p: 0.019) and poorly differentiated histological type (HR: 91.06, 95% CI: 7.31-1134.32, p: 0.002) had statistically significant impacts on overall survival. Conclusions: Selection of the optimal surgical management, via either nephrectomy or nephroureterectomy, depends on the origin of the primary lesion and represents the mainstay of treatment. A suspicion from the urologist is needed for the identification and optimal treatment of these rare tumors.