Renal Mass: A Confusing Feature of Sarcoidosis

Kidney manifestations of sarcoidosis

Renal involvement is a clinically relevant organ manifestation of sarcoidosis, leading to increased morbidity and complications. Although the exact incidence remains unknown, renal disease is likely to occur in up to one third of all sarcoidosis patients. Every patient with newly diagnosed sarcoidosis should receive a renal work-up and screening for disrupted calcium metabolism. Amid various forms of glomerulonephritis, granulomatous interstitial nephritis is the most common one, but it rarely leads to renal impairment. Histologically, granulomas can be absent. Nephrocalcinosis and nephrolithiasis are frequent forms when hypercalcaemia or hypercalciuria occur. Drugs used for treatment of systemic sarcoidosis can also cause renal damage. Due to its high heterogeneity, renal sarcoidosis can be difficult to treat. Glucocorticoids and various immunosuppressive treatments have been proven to be effective based on case series, but clinical trials are lacking. A treatment guideline for renal sarcoidosis is urgently needed. In this review article, we present an overview of the different forms of renal sarcoidosis and the diagnostic steps to confirm renal involvement; in addition, we provide insights on the management and available treatments. A better understanding regarding the pathogenesis of sarcoidosis is the key for the development of more specific, targeted therapies.

Renal sarcoidosis: approach to diagnosis and management

PURPOSE OF REVIEW

The purpose of this article is to provide understanding of renal sarcoidosis, the different types of renal sarcoidosis, disease burden of renal involvement, and treatment options.

RECENT FINDINGS

The frequency of renal involvement seems to be underestimated, but renal sarcoidosis represents a relevant group of organ manifestations and significantly adds to the patient's morbidity. Because histopathological analysis of renal biopsy specimens can reveal various entities, a diagnostic workup is necessary in every patient with sarcoidosis.

SUMMARY

If systematically screened for renal manifestations are likely to occur in up to 25-30% of all sarcoidosis patients. The most common histological form of renal sarcoidosis is the granulomatous interstitial nephritis; however, granulomas can be absent. Furthermore, one can find various forms of secondary glomerulonephritis. In cases with dysregulated calcium homeostasis, nephrocalcinosis and nephrolithiasis are commonly detectable kidney diseases. AA amyloidosis or renal masses because of granuloma formation are considered to be rare manifestations. In addition to glucocorticoids various immunosuppressive treatments such as tumor necrosis factor alpha inhibitors have proven to be effective based on case series.

Pulmonary sarcoidosis as a cause of intermittent fever of unknown origin in a hemodialysis patient with renal cell carcinoma: A case report and literature review

Hemodialysis patients have weakened immune systems and can exhibit fever due to various causes. Herein, we describe the case of a 61-year-old hemodialysis patient who exhibited intermittent low-grade fever after a pacemaker had been implanted 2 months before due to sick sinus syndrome. She had a medical history of subcutaneous sarcoidosis and uveitis. Active pulmonary sarcoidosis was diagnosed based on elevated soluble interleukin-2 receptor, elevated lysozyme level, and gallium-67 scintigraphy uptake in hilar and mediastinal lymph nodes. She was also diagnosed with renal cell carcinoma via contrast computed tomography. However, because her C-reactive protein level remained normal, the possibility of neoplastic fever was considered low. After the initiation of prednisolone administration, her fever gradually disappeared. Her serum soluble interleukin-2 receptor and lysozyme level improved in parallel with the enlargement of the mediastinal lymph node and gallium-67 scintigraphy uptake.

Sarcoidosis presenting as severe renin-dependent hypertension due to kidney vascular injury

Renal sarcoidosis embraces a wide variety of clinical patterns. Renal vascular involvement has seldom been reported and usually in the setting of systemic vasculitis. We report the case of a 22-year-old patient in whom inaugural manifestation of renal sarcoidosis consisted of severe hypertension associated with bilateral perfusion defects and tumour-like nodules. In the setting of renal sarcoidosis, our case suggests that renin-dependant hypertension may arise from renal ischaemia as a result of extrinsic compression of kidney blood vessels due to severe granulomatous inflammation.