Diagnostic Journey to Granulomatosis with Polyangiitis with Rare Hepatic and Suspected Splenic Involvement: A Case Report.

Sarcoidosis and granulomatosis with polyangiitis (GPA) are the most common non-infectious causes of granulomatous lung disease. However, they can sometimes be difficult to distinguish due to overlapping clinical, radiological, and histopathological features. A 54-year-old man was considered to have sarcoidosis in 2018. Treatment with glucocorticoids led to improvement, but the patient self-discontinued it in 2021. In January 2022, he was readmitted due to recurrent cough and fatigue, who then developed purpuric lesions on the lower extremities, renal impairment, and abnormal results for liver function tests. Chest computed tomography showed lymphadenopathy, consolidations, and nodular lesions. Liver and spleen lesions were detected on abdominal ultrasound, and liver biopsy was performed revealing necrotizing granulomas. Strongly positive proteinase 3 (PR3) anti-neutrophil cytoplasmic antibody (ANCA) together with clinical, radiological, and histopathological findings supported the diagnosis of GPA. Treatment with methylprednisolone and cyclophosphamide led to clinical and partial laboratory improvement. Unfortunately, the patient died suddenly, reportedly in association with massive hemoptysis. Ongoing reassessment during the disease course is essential for accurate diagnosis and optimal management. This case highlights the diagnostic challenges posed by overlapping features of sarcoidosis and GPA, and the rare presence of hepatic necrotizing granulomas with concurrent radiologically suspected granulomatous splenic involvement. The limited data reported in the literature make this case particularly unique and diagnostically significant.