[Extrapulmonary sarcoidosis with multiorgan involvement: a complex case with renal, neurological, and...

Systemic sarcoidosis can occur without pulmonary involvement and may present exclusively with extrapulmonary manifestations, thereby mimicking infections, autoimmune diseases, or malignancies.

The case of a 60-year-old female patient with pronounced cachexia (BMI 14 kg/m²), hypercalcemia, and multiorgan involvement is presented. Histology revealed non-caseating granulomas in gastric biopsies (granulomatous gastritis) as well as granulomatous interstitial nephritis with a tubular proteinuria pattern on renal biopsy. Imaging revealed no evidence of pulmonary involvement. Markedly elevated serum angiotensin-converting enzyme and soluble interleukin‑2 receptor levels, together with cerebrospinal fluid and MRI findings, were consistent with neurosarcoidosis. As the disease progressed, posterior reversible encephalopathy syndrome developed, presenting with seizures and transient cortical blindness. An extensive differential diagnostic workup, particularly for lymphoma, tuberculosis, and systemic vasculitis, was negative. The clinical course was complicated by percutaneous endoscopic gastrostomy-associated Enterococcus faecium peritonitis and Candida albicans sepsis. After stabilization and infection control, high-dose corticosteroid therapy was initiated, resulting in partial improvement of renal function and neurological symptoms.

This case highlights the diagnostic and therapeutic challenges of life-threatening, purely extrapulmonary sarcoidosis with renal, gastrointestinal, and neurological manifestations. Early histological confirmation, thorough exclusion of relevant differential diagnoses, and multidisciplinary management are essential, particularly in balancing immunosuppression with infection control.