{
  "abstract": "A 67-year-old male presented to the emergency department with diarrhoea, weight loss and ascites. This was on a background of chronic myelomonocytic leukaemia (CMML). Laboratory testing demonstrated severe hypoalbuminaemia (16 g/L, normal 30–44 g/L), hypoproteinaemia (33 g/L, normal 60–80 g/L) and hypogammaglobulinaemia (IgG 2.75 g/L, IgM <0.20 g/L), without nephrotic range proteinuria detected on 24-hour urine protein collection or cardiac disease being identified on transthoracic echocardiogram. CT abdomen revealed large-volume ascites and splenomegaly without other radiological features of portal hypertension, namely varices (figure 1). Splenomegaly was deemed to be secondary to the patient’s underlying CMML which was unchanged from previous imaging. Ascitic fluid analysis showed a low serum ascites albumin gradient (9 g/L) with low ascitic fluid protein (10 g/L) which was inconsistent with a diagnosis of portal hypertension. Spot faecal alpha-1 antitrypsin was elevated at 11.6 mg/g (normal <1.5 mg/g). Gastroscopy, colonoscopy and video capsule endoscopy were macroscopically normal. Random colonic biopsies taken in the ascending and descending colon demonstrated expansion of the lamina propria with a markedly increased population of CD117-positive cells on immunohistochemistry consistent with mast cells (>100/hpf) (figure 2). Serum tryptase was markedly elevated at 90.3 µg/L (normal 0–11.0 µg/L). A KIT D816V mutation was detected on bone marrow biopsy, fulfilling WHO criteria for systemic mastocytosis with an associated haematologic neoplasm (SM-AHM). Peripheral blood next-generation sequencing demonstrated additional myeloid-associated mutations of ASXL1, KIT and SETBP1 consistent with a diagnosis of SM-AHM. The patient was treated with antihistamines, mast cell stabilisation therapy and midostaurin (a type III receptor tyrosine kinase inhibitor that inhibits D816V-mutated KIT), with improvement in stool frequency to twice daily with a formed stool. The patient’s serum albumin and serum tryptase improved to 29 g/L and 55.1 µg/L, respectively. SM-AHM is an exceedingly rare cause of protein-losing enteropathy, with diagnosis requiring a high level of suspicion.1 Treatment is directed at mast cell activation and the underlying haematological disorder.2 This case highlights the importance of maintaining a broad differential in patients who present with diarrhoea, particularly in the context of an underlying haematological neoplasm. In addition to this, it also highlights the importance of histopathological assessment in symptomatic patients in whom endoscopy is macroscopically normal.",
  "authors": [
    {
      "affiliations": [
        "Department of Gastroenterology and Hepatology, Campbelltown Hospital, Campbelltown, New South Wales, Australia",
        "Faculty of Medicine, St Vincent’s Clinical School, University of New South Wales, Sydney, New South Wales, Australia"
      ],
      "name": "Robert S O’Neill"
    },
    {
      "affiliations": [
        "Department of Gastroenterology and Hepatology, Campbelltown Hospital, Campbelltown, New South Wales, Australia"
      ],
      "name": "Li-Han Goh"
    },
    {
      "affiliations": [
        "Australian Clinical Labs Ltd, Clayton, Victoria, Australia"
      ],
      "name": "Sowmya Sharma"
    },
    {
      "affiliations": [
        "Department of Haematology, Campbelltown Hospital, Campbelltown, New South Wales, Australia"
      ],
      "name": "Eleanor Allison"
    },
    {
      "affiliations": [
        "Department of Haematology, Campbelltown Hospital, Campbelltown, New South Wales, Australia"
      ],
      "name": "Brendan Beaton"
    },
    {
      "affiliations": [
        "Department of Gastroenterology and Hepatology, Campbelltown Hospital, Campbelltown, New South Wales, Australia"
      ],
      "name": "Christine Verdon"
    }
  ],
  "title": "Unique case of a protein-losing enteropathy secondary to systemic mastocytosis with an associated haematologic neoplasm",
  "uid": "25a05a0b-a71d-5e2a-9b66-dedb41f9b07d"
}