Christopher B. Tan

Gastrointestinal Stromal Tumors: A Review of Case Reports, Diagnosis, Treatment, and Future Directions

Gastrointestinal stromal tumor (GIST) is a nonepithelial, mesenchymal tumor first described by Mazur and Clark in 1983. Since then, its molecular biology has been studied in great detail. Special interest in the role of tyrosine kinase in its regulation has been the target by different drug research. Mutation in c-kit exons 9, 11, 13, 17 and PDGFRA mutation in exons 12, 14, 18 are responsible for activation of gene signaling system resulting in uncontrolled phosphorylation and tissue growth. However, 5 to 15% of GISTs does not harbor these mutations, which raises additional questions in another alternate signaling pathway mutation yet to be discovered. Diagnosis of GISTs relies heavily on KIT/CD117 immunohistochemical staining, which can detect most GISTs except for a few 3% to 5% that harbors PDGFRA mutation. Newer staining against PKC theta and DOG-1 genes showed promising results but are not readily available. Clinical manifestation of GISTs is broad and highly dependent on tumor size. Surgery still remains the first-line treatment for GISTs. The advancement of molecular biology has revolutionized the availability of newer drugs, Imatinib and Sunitinib. Together with its advancement is the occurrence of Imatinib/Sunitinib drug resistance. With this, newer monoclonal antibody drugs are being developed and are undergoing clinical trials to hopefully improve survival in patients with GISTs.

Hepatic sarcoidosis presenting as portal hypertension and liver cirrhosis: case report and review of the literature.

Systemic sarcoidosis is a disease of unknown etiology, with the liver being the third most commonly affected organ. Most cases of hepatic sarcoidosis are not clinically apparent, but a few can progress to liver cirrhosis, portal hypertension and ultimately liver failure. The diagnosis of hepatic sarcoidosis is difficult, considering that no single laboratory test or radiographic finding can definitively diagnose this systemic disease. Diagnosis of hepatic sarcoidosis relies heavily on histopathologic evaluation of two or more organs, a diagnostic modality that is invasive and may not be applicable to all patients. The treatment of hepatic sarcoidosis is challenging, with no large randomized controlled trials done to date. Physicians must be aware of the complications of hepatic sarcoidosis, and must include the same in the differential diagnosis of liver cirrhosis. We present a case of hepatic sarcoidosis complicated by portal hypertension and liver cirrhosis.

Blastocystis hominis and Endolimax nana Co-Infection Resulting in Chronic Diarrhea in an Immunocompetent Male.

Blastocystis hominis and Endolimax nana exist as two separate parasitic organisms; however co-infection with the two individual parasites has been well documented. Although often symptomatic in immunocompromised individuals, the pathogenicity of the organisms in immunocompetent subjects causing gastrointestinal symptoms has been debated, with studies revealing mixed results. Clinically, both B. hominis and E. nana infection may result in acute or chronic diarrhea, generalized abdominal pain, nausea, vomiting, flatulence and anorexia. We report the case of a 24-year-old immunocompetent male presenting with chronic diarrhea and abdominal pain secondary to B. hominis and E. nana treated with metronidazole, resulting in symptom resolution and eradication of the organisms. Our case illustrates that clinicians should be cognizant of both B. hominis and E. nana infection as a cause of chronic diarrhea in an immunocompetent host. Such awareness will aid in a timely diagnosis and possible parasitic eradication with resolution of gastrointestinal symptoms.

Collagenous enterocolitis and maturity onset type 1 diabetes manifesting as uraemia, malabsorption and extreme weight loss.

A 37-year-old patient with type 1 diabetes had been recently diagnosed with collagenous colitis (CC) after sigmoidoscopy. She rapidly progressed from a fortnight of watery diarrhoea, to a malabsorptive state with severe dehydration and acute kidney injury. This necessitated admission to an intensive care unit for emergency dialysis. She was subsequently diagnosed with collagenous enterocolitis affecting gastric, small bowel and colonic mucosa which required systemic steroid therapy. Physicians caring for patients with CC should be aware of the potential extreme manifestations of upper gastrointestinal collagenous deposition.

Predictors of significant coronary artery disease in atrial fibrillation: are cardiac troponins a useful measure

BACKGROUND Cardiac Troponin I (cTnI) is frequently measured in patients presenting with symptomatic atrial fibrillation (AF). The significance of elevated cTnI levels in this patient cohort is unclear. We investigated the value of cTnI elevation in this setting and whether it is predictive for significant coronary artery disease (sCAD). METHODS We conducted a retrospective, single-center, case-control study of 231 patients who presented with symptomatic AF to The Prince Charles Hospital emergency department, Brisbane, Australia between 2006 and 2014. Patients who underwent serial cTnI testing and assessment for CAD were included. Clinical variables that are known to predict CAD and could potentially predict cTnI elevation were collected. Binary logistic regression was performed to identify predictors of sCAD and cTnI elevation. RESULTS Cardiac Troponin I elevation above standard cut off was not predictive for sCAD after adjustment for other predictors (OR 1.62, 95% CI 0.79-3.32. p=0.19). However, the highest cTnI concentration value (cTnI peak) was predictive for sCAD (OR 2.02, 95% CI 1.02-3.97, p=0.04). Dyspnea on presentation (OR 4.52, 95% CI 1.87-10.91, p=0.001), known coronary artery disease (OR 3.44, 95% CI 1.42-8.32, p=0.006), and ST depression on the initial electrocardiogram (OR 2.57, 95% CI 1.11-5.97, p=0.028) predicted sCAD in our cohort, while heart rate on initial presentation was inversely correlated with sCAD (OR 0.99, 95% CI 0.971-1.00, p=0.034). CONCLUSION Troponin elevation is common in patients presenting to hospital with acute symptomatic AF and it is not a reliable indicator for underlying sCAD in this patient cohort. However, cTnI peak was a predictor of significant coronary artery disease.

Staphylococcal Sepsis with Multiple Abscesses, Urinary Tract Infection, and Bilateral Renal Vein Thrombosis in a Patient with Uncontrolled Diabetes Mellitus

We report a case of staphylococcal sepsis with vascular complications including peripheral emboli and renal vein thrombosis. Bilateral renal vein thrombosis has not been reported as a complication of Staphylococcus aureus (SA) axillary abscess. Uncontrolled diabetes was the only detected predisposing medical condition. The patient was treated successfully with incision and drainage of soft-tissue abscesses and intravenous antibiotic for six weeks and with anticoagulation for renal vein thrombosis.

Pathologic Rupture of the Spleen in Mantle-Cell-Type Non-Hodgkin’s Lymphoma

Mantle cell lymphoma (MCL) accounts for less than 10 percent of all non-Hodgkins lymphoma (NHL). Pathologic or spontaneous rupture of the spleen has been reported in patients with lymphoma; however only 5 cases have been reported in patients with MCL. Although splenomegaly occurs frequently in patients with MCL, spontaneous splenic rupture is rare. We present a case of a 51-year-old female with MCL, who presented to the medical emergency room with splenic rupture. This case illustrates that clinicians should be aware of the incidence and presentation of patients with MCL and spontaneous splenic rupture, as early detection and heightened suspicion may prevent potentially fatal outcomes.

A solid organising cryptogenic liver abscess and its association with a colonic tubullovillous adenoma

Cryptogenic liver abscess (CLA) is a well-known disease entity that has puzzled clinicians for centuries. With the advancement of diagnostic modalities, comes the decreasing incidence of liver abscess labelled as ‘cryptogenic’ in nature. Colonic diseases have been identified as a possible underlying condition found in patients with liver abscesses. Although rare, tubullovillous adenomas have been implicated as one of the colonic causes of a CLA. We present a case of a CLA in a 53-year-old man with a potentially associated tubullovillous adenoma found via colonoscopy.

Acute Legionella pneumophila infection masquerading as acute alcoholic hepatitis

A middle-aged man had deteriorated rapidly in hospital after being misdiagnosed with acute alcoholic hepatitis. Acute Legionnaires disease (Legionellosis) was subsequently diagnosed on rapid antigen urinary testing and further confirmed serologically. This led to appropriate antibiotic treatment and complete clinical resolution. Physicians caring for patients with alcohol-related liver disease should consider Legionella pneumophila in their differential diagnosis even with a paucity of respiratory symptoms.