Concurrent Langerhans Cell Histiocytosis and Autoimmune Hepatitis: A Case and Review of the Literature.

Autoimmune hepatitis (AIH) and Langerhans cell histiocytosis (LCH) are two independently rare disease processes that can have similar presentations. We present a unique, complex case that required a multidisciplinary approach to ultimately diagnose and treat the patient. A 20-year-old male with no significant history presented with worsening jaundice, diffuse, pruritic rash, and abdominal pain over one month. On admission, the patient's labs showed significantly elevated liver function tests (LFTs), eosinophilia, and anemia. The exam was notable for diffuse lymphadenopathy (LAD), hepatosplenomegaly, and a diffuse, non-blanching, morbilliform rash. Interdisciplinary workup was notable for positive anti-smooth muscle antibody (ASMA) and anti-neutrophilic antibody (ANA). A liver biopsy showed severe inflammation with interface activity, consistent with AIH. A lymph node (LN) biopsy showed findings consistent with LCH, including histiocyte clusters. He was started on high-dose steroids with LAD/LFT improvement; yet, his course was complicated by a gastrointestinal (GI) bleed requiring a hemicolectomy. The patient was transferred to a larger referral center where he continued to improve with steroids and was ultimately discharged. This case was notable for an LN biopsy showing histiocyte clusters with reniform nuclei, nuclear grooves, and eosinophils with immunohistochemical stains positive for S-100, CD1a, fascin, langerin, CD45, and CD68, consistent with LCH. The resected colon showed atypical histiocyte proliferation positive for fascin, CD4, and CD68. Other findings, including elevated LFTs, ASMA, and a liver biopsy showing inflammation with interface activity, eosinophils, plasma cells, and characteristic fibrosis, supported a diagnosis of AIH. In either case, steroids were indicated.