Unilateral Renal Hypoplasia




Wieters, Matthew
Tran, Kylie
Smith, Zane
Thayyil, Hibaa
Weber, Landan
Fisher, Cara L.


0000-0003-0257-3614 (Fisher, Cara L.)

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Background: Unilateral renal hypoplasia can occur as a result of, or in conjunction with, comorbidities such as hypertension, vascular diseases, pyelonephritis, and congenital developmental disorders. Contralateral renal compensation with hypertrophy of the sister kidney is one of the common sequelae of unilateral renal hypoplasia in addition to chronic renal failure (CRF) due to dysfunctional filtration and impaired blood pressure regulation. The incidence of renal hypoplasia according to epidemiological studies is 1 in 400 births. This case report examines the potential causes of a hypoplastic kidney found in the retroperitoneum of an 80-year-old female cadaver. Case Information: Detailed dissection of the left retroperitoneal space of the subject revealed a morphologically hypoplastic kidney with dimensions of 40 mm in length, 21 mm in width, and 13.5 mm in thickness. Hemisection of the kidney revealed cortical thinning as well. Contralateral compensation by the right kidney led to hypertrophic dimensions of 112 mm in length, 64 mm wide, and 46 mm in thickness. Average kidney pole-to-pole length is around 102 mm for the left kidney and 99 mm for the right kidney in women aged 80-89 years. Blood supply to the hypoplastic kidney appeared normal initially, however, upon measurement, the left renal artery was found to be much narrower at 1.72 mm in width in comparison to a typical renal artery diameter of 5 mm. The left renal vein exiting the hypoplastic kidney measured 57 mm in length compared to an average left renal vein length of 60-100 mm. The ureter exiting the left hypoplastic kidney was 1 mm wide while the right ureter measured 3.75 mm in width. No clear pathological characteristics were visualized in the kidney, such as cysts or tissue dysplasia. An additional finding of this case was an abdominal aortic aneurysm (AAA) measuring 140.5 mm from the inferior base at the common iliac artery bifurcation up to the superior border where the superior mesenteric artery branches. The AAA measured 40 mm wide and 27.75 mm in thickness. Conclusions: The compensatory enlarged right kidney and altered dimensions of the artery and vein associated with the hypoplastic kidney indicate potential for abnormal vasculature affecting overall kidney growth and function. The thin cortex also indicates reduced nephrotic function. Renal hypoplasia and impaired renal function predispose an individual to conditions such as hypertension or chronic renal failure. If patients present with a hypoplastic kidney, physicians can monitor potential chronic conditions and provide proper intervention. Likewise, physicians should be aware that patients with chronic cardiovascular and renal conditions are at a greater risk of developing an atrophic kidney if left untreated. Although a definitive etiology is unable to be determined due to a lack of sufficient past medical history, investigation into the relationships of anatomical variants adds to the current literature and understanding of this condition.