Systemic mastocytosis – a rare case of dramatically increased liver stiffness

Aims: Liver stiffness measured by transient elastography is a novel and non-invasive surrogate for liver fibrosis. Several conditions, however, have been identified that increase liver stiffness independently of fibrosis e.g. acute viral hepatitis, bile duct obstruction, and cardiac insufficiency. Although most of these interferences can be easily diagnosed by clinical examination, ultrasound, and basic blood tests, transient elastography still needs to prove whether it is a reliable method in clinical routine. We here report on a patient with drastically increased liver stiffness that was eventually caused by systemic mastocytosis.

Methods and results: A 55 year old man presented to our department with weight loss and nocturnal pruritus. Blood tests showed elevated liver enzyme counts (GOT 65U/l, GPT 74U/l, GGT 329U/l, AP 830U/l, Bilirubin 2,4mg/dl), an increased white blood cell count (15,8/nl), decreased platelets (65/nl), a slightly increased CRP. Liver synthesis parameters were normal. Abdominal ultrasound showed ascites, hepatomegaly without sonographic signs of cirrhosis and splenomegaly (16.3×6.1 ×5.9cm). Esophgeal varices were excluded by upper endoscopy. Liver stiffness measured by Fibroscan® (Echosens, France) was repeatedly determined at 75.0 kPa. A combination of hepatomegaly, splenomegaly and ascites with liver stiffness values of 75kPa is highly suggestive of liver cirrhosis even despite the lack of nodular surface in the ultrasound examination. However, liver biopsy excluded liver cirrhosis. Instead, parenchyma, venous sinuus and bile ducts were infiltrated by proliferating spindle-shaped cells. Immunohistochemistry identified these cells as mast cells. A CT scan detected disseminated osseous metastases. Based on these findings, the diagnosis of systemic mastocytosis was established.

Conclusion: This case demonstrates that liver stiffness can also be dramatically increased by conditions such as mast cell infiltration. In case of doubt a liver biopsy is still the only way to clarify the underlying cause of increased liver stiffness.