Sarcoidosis in a young child with Alagille syndrome: a case report.

We report a now 6-year-old African-American male with both Alagille syndrome and pediatric sarcoidosis. With a prior JAG1 mutation positive diagnosis of Alagille syndrome, he presented to the hospital with a subacute, predominantly respiratory febrile condition, eventually diagnosed as sarcoidosis. A liver biopsy revealed paucity of bile ducts and scattered epithelioid granulomas, while a skin biopsy showed granulomatous angiitis, a manifestation of sarcoidosis not yet reported in a pediatric patient. He has subsequently been treated with corticosteroids, mycophenolate mofetil, and infliximab with clinical response. Alagille syndrome and sarcoidosis have not yet been reported in the medical literature in the same patient to the best of our knowledge. We briefly review these two seemingly unrelated conditions and propose a possible common pathogenic mechanism.