Introduction: Mastocytosis is a clonal, neoplastic mast cell proliferation. It may be divided into cutaneous and systemic mastocytosis. In cutaneous mastocytosis, the course of disease is often indolent. If other organs with or without skin lesions are involved, WHO-criteria for systemic mastocytosis are fulfilled. If organ function is additionally impaired (C-findings) in systemic mastocytosis, an aggressive course of disease can be assumed. Sclerosing cholangitis is a chronic disease of bile ducts in or outside the liver leading to inflammation of bile ducts with obstructive fibrosis and consecutive development of liver fibrosis and cirrhosis. The underlying cause of the disease is unknown. There is an association with inflammatory bowel disease.
Case presentation: Here we present a case of a 26 year old male patient with aggressive systemic mastocytosis with involvement of the liver mimicking primary sclerosing cholangitis. The patient presented in emergency department in reduced general condition complaining about progredient weakness, fatigue, and vomiting. He reported on a previous diagnosis of ulcerative colitis, primary sclerosing cholangitis, systemic mastocytosis and liver cirrhosis in an external hospital. Routine laboratory diagnostic test showed cholestasis with elevated levels of alkaline phosphatase and mildly elevated gamma glutamyl transferase levels. Further laboratory tests gave no indication for other underlying diseases, such as viral infection, autoimmune disease or drug-induced/toxic liver injury. Furthermore, gastroscopy and colonoscopy was done. Pathological examination revealed multifocal, dense clusters of more than 15 large, in part spindle shaped cells immunoreactive with antibodies against the mast cell markers CD117/c-KIT and tryptase. Taken together diagnosis of systemic mastocytosis was established and the previous diagnosis of primary sclerosing cholangitis was critically questioned. During follow-up, iliac crest biopsy was performed, showing bone marrow infiltrates of mast cells with aberrant immune phenotype with coexpression of CD25, CD117, and tryptase with c-KIT point mutation KIT D816V. In addition, liver biopsy was done showing infiltrates of clustered atypical mast cells with positivity for CD117 and tryptase in the portal tracts, acinar liver parenchyma, bile ducts and vessels within fibrotic liver tissue. Cytokeratin 7 immunohistochemistry demonstrated significant degenerative changes of the original bile ducts, ductular proliferations, and ductular metaplasia of periportal hepatocytes indicating chronic cholestasis. No signs of specific cholangiopathies were found. In summary, aggressive systemic mastocytosis was diagnosed.
Conclusion: Aggressive systemic mastocytosis is a rare cause of liver injury and may therefore be misdiagnosed. Systemic mastocytosis affecting the liver may involve bile ducts in a fashion typical for other causes of cholangitis, i.e. primary sclerosing cholangitis.
Corresponding author: Waldburger, Nina
E-Mail:
Nina.Waldburger@med.uni-heidelberg.de
