From the Guidelines
Diagnosing reninoma requires a comprehensive approach that includes clinical evaluation, laboratory tests, and imaging studies, with a focus on identifying the characteristic clinical triad of hypertension, hypokalemia, and elevated plasma renin activity. When suspecting a renal mass like reninoma, clinicians should obtain high-quality, multiphase, cross-sectional abdominal imaging to optimally characterize and clinically stage the renal mass, as recommended by the American Urological Association guideline 1. This approach should include:
- Assessment of tumor complexity
- Degree of contrast enhancement
- Presence or absence of fat Additionally, a comprehensive metabolic panel, complete blood count, and urinalysis should be performed, along with chest imaging to evaluate for possible thoracic metastases 1. Evaluation for proteinuria, CKD, hematuria, hypercalcemia, hepatic dysfunction, and blood count abnormalities is also crucial, as these may reflect poor health status or advanced cancer. In the context of reninoma, specific laboratory tests such as measuring plasma renin activity or concentration, aldosterone levels, and the aldosterone-to-renin ratio can help confirm the diagnosis. Imaging studies like contrast-enhanced CT or MRI of the kidneys can detect reninomas, which are typically small, well-circumscribed masses within the kidney. Selective renal vein sampling for renin may be necessary to confirm the diagnosis and precisely locate the tumor, especially in cases where imaging results are inconclusive.
From the Research
Diagnostic Evaluation of Reninoma
To diagnose reninoma, several diagnostic approaches can be employed, including:
- Imaging studies to identify the presence of a lesion in the renal cortex 2
- Selective venous catheterization following administration of an angiotensin-converting enzyme inhibitor (ACE-I) to confirm the presence of a renin-producing lesion 2
- Measurement of plasma renin activity (PRA) and aldosterone levels to assess for hypersecretion of renin 2, 3, 4, 5
- Renal vein renin sampling with lateralization to identify the site of excessive renin production 4, 5
- Contrast CT or magnetic resonance imaging of the kidneys to diagnose reninoma 4
Biochemical Markers
Biochemical markers that can aid in the diagnosis of reninoma include:
- Elevated plasma renin activity (PRA) 2, 3, 4, 5
- Elevated aldosterone levels 2, 3, 4, 5
- Hypokalemia and metabolic alkalosis on the first blood sample drawn before any treatment is instituted 4
Imaging Modalities
Imaging modalities that can be used to diagnose reninoma include: