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Kidney Week

Abstract: FR-PO135

Two Cases of Atypical Sarcoidosis Presenting with AKI: Clinical Significance of Sequential Fluorodeoxyglucose (FDG) Positron Emission Tomography (PET)/CT Images

Session Information

Category: Acute Kidney Injury

  • 102 AKI: Clinical, Outcomes, and Trials

Authors

  • Mohri, Yui, Department of Nephrology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
  • Yamamoto, Shinya, Department of Nephrology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
  • Shimizu, Yoko, Department of Nephrology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
  • Koyasu, Sho, 2) Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University, Kyoto, Japan
  • Yanagita, Motoko, Department of Nephrology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
Introduction

Refractory hypercalcemia can be caused by sarcoidosis, which can induce severe and irreversible renal impairment without appropriate therapy. Therefore, clinicians must correctly diagnose sarcoidosis using serological, radiological, and pathological evaluation.

Case Description

Case1: A 76-year-old female was admitted to our hospital with general fatigue. Laboratory tests revealed renal dysfunction (sCre: 2.77 mg/dL), hypercalcemia (12.9 mg/dL). The levels of activated vitamin D was elevated.No respiratory, skin or eye lesions were observed. Renal biopsy revealed no granulomatous lesions. PET/CT showed accumulation in the muscles of the whole body with Tiger-man sign. Muscle biopsy showed granuloma with multinucleated giant cells. The patient was finally diagnosed with muscular sarcoidosis. After starting oral prednisolone 0.7 mg/kg/day, hypercalcemia and renal dysfunction improved. Three months later, PET/CT showed that the accumulation had disappeared.
Case 2: A 74-year-old male was referred to our hospital with swallowing pain and diagnosed with esophageal cancer. PET/CT showed accumulation in the hilar and mediastinal lymph nodes and bilateral thigh muscles. The patient started chemotherapy. Two months later, repeated PET/CT showed reduced accumulation in the lymph nodes, but new accumulations in the lower leg . Blood tests revealed renal dysfunction (sCre: 3.5 mg/dL) and hypercalcemia (14.3 mg/dL). Muscle biopsy revealed a non-caseating epithelioid cell granuloma. The patient was finally diagnosed with sarcoidosis. Renal biopsy showed lymphocytic infiltration of interstitial and necrotizing vasculitis. Anti-neutrophil cytoplasmic antibodies were negative. After starting oral prednisolone 0.8 mg/kg/day, hypercalcemia and renal dysfunction improved.

Discussion

PET/CT is useful for diagnosis of sarcoidosis, especially in patients without typical organ lesions and in cancer patients with hypercalcemia and lymphadenopathy. While sequential PET/CT in Case 1 clearly showed a good response to treatment, that in Case 2 suggested that emerging muscle lesions contributed to vitamin D activation. In addition, renal biopsy of Case 2 revealed vasculitis, which is a rare complication in patients with sarcoidosis. As previously reported, cancer may trigger sarcoidosis and vasculitis via immune or macrophage abnormalities.