# A Rare Case of Isolated Extrapulmonary Sarcoidosis With Renal Involvement Sans Pulmonary Findings: Diagnostic Challenges and Clinical Insights

## TL;DR

This paper describes a rare case of sarcoidosis affecting the kidneys without lung involvement, highlighting the diagnostic challenges and the importance of considering sarcoidosis in atypical presentations.

## Contribution

The novelty lies in presenting a rare case of isolated renal sarcoidosis without pulmonary or skin findings, emphasizing the need for broader diagnostic awareness.

## Key findings

- The patient had noncaseating granulomas in a palm biopsy, confirming sarcoidosis.
- The case showed that sarcoidosis can present with renal failure and hypercalcemia without lung or skin symptoms.
- Treatment with prednisolone led to remission, supporting corticosteroid use in atypical sarcoidosis cases.

## Abstract

The cause of sarcoidosis is unknown, and it affects multiple systems with granulomas. Lung lesions are typical, but extrapulmonary findings, especially lymphadenopathy, are present in a significant number of cases. Isolated renal involvement is rare. The presence of noncaseating granulomas on biopsy is a hallmark of sarcoidosis.

We present the case of a 59-year-old male with recurrent renal stones who presented with renal failure. The initial diagnosis was challenging due to normal chest imaging and no pulmonary involvement. However, his delayed presentation of calcinosis cutis, an increase in angiotensin-converting enzyme (ACE) level, and the biopsy of the palm lesion with noncaseating granulomas helped us reach the diagnosis. He was started on prednisolone and achieved remission. The report also intends to show that patients with sarcoidosis can present without lung involvement, and physicians should consider sarcoidosis as their differential diagnosis for idiopathic hypercalcemia even if it has no lung or skin findings.