Publications by authors named "Evan Yung"

5 Publications

  • Page 1 of 1

Intestinal Metaplasia of the "Cardia": Accurate Differentiation of Gastric or Esophageal Origin With an Expanded Biopsy Protocol.

Am J Surg Pathol 2021 Jul;45(7):945-950

Emeritus of Pathology, Keck School of Medicine, University of Southern California.

Whether intestinal metaplasia (IM) distal to the endoscopic gastroesophageal junction (GEJ), that is, the cardia, is gastric or esophageal or both is controversial. Biopsies from this region are believed to be unreliable in resolving this issue and are not recommended. Our objective was to develop an accurate method of histologic diagnosis for IM of the cardia. An expanded biopsy protocol was employed in 986 patients irrespective of indication for endoscopy. This sampled columnar lined esophagus (CLE) when present, the endoscopic GEJ defined by the proximal limit of rugal folds, the area 1 cm distal to the GEJ, and distal stomach. The prevalence and associations of IM in these 4 locations were evaluated. IM was found in 79/91 patients with CLE above the GEJ. This was significantly associated with IM at the GEJ in 40/79 patients (P<0.001). The biopsy taken distal to the endoscopic GEJ had IM in 21/79 patients. No patient with CLE had IM in the distal stomach. In patients without CLE, IM was present at or distal to the endoscopic GEJ in 221 patients. In 32 patients, this was significantly associated with IM in the distal stomach (P<0.001). The remaining 189/986 (19.2%) patients had IM limited to the GEJ region. These data, in association with recent evidence, indicate that IM limited to the area distal to the GEJ in patients without distal gastric IM represents microscopic Barrett esophagus in a dilated distal esophagus. This is presently mistaken for IM of the proximal stomach because of a flawed endoscopic definition of the GEJ.
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http://dx.doi.org/10.1097/PAS.0000000000001665DOI Listing
July 2021

An unusual presentation of post gastric bypass hypoglycemia with both postprandial and fasting hypoglycemia

Endocrinol Diabetes Metab Case Rep 2018 Oct 31;2018:18-0089. Epub 2018 Oct 31.

Division of Endocrinology, Diabetes, and Metabolism, Keck School of Medicine, LAC+USC Medical Center, University of Southern California, Los Angeles, California, USA.

There has been an increasing awareness of post gastric bypass hypoglycemia (PGBH). Histopathologic findings from such patients who underwent partial/total pancreatomy, however, can vary widely from minimal changes to classic nesidioblastosis, making the pathologic diagnosis challenging. PGBH typically presents as postprandial hypoglycemia, as opposed to insulinoma, which presents as fasting hypoglycemia. Herein, we describe an unusual case of a patient with PGBH who initially presented with postprandial hypoglycemia three years after surgery, but later developed fasting hyperinsulinemic hypoglycemia as the disease progressed. Our hypothesis for this phenomenon is that this disease is progressive, and later in its course, the insulin release becomes dissociated from food stimulation and is increased at baseline. Future studies are needed to investigate the prevalence as well as etiology of this progression from postprandial to fasting hypoglycemia. Learning points: •• There has been an increasing awareness of post gastric bypass hypoglycemia (PGBH). •• Histopathologically, PGBH can vary from minimal changes to nesidioblastosis. •• Although uncommon, patients with PGBH after Roux-en-Y gastric bypass may present with both postprandial and fasting hyperinsulinemic hypoglycemia as disease progresses. •• Our hypothesis for this phenomenon is that the insulin release becomes dissociated from food stimulation and is increased at baseline with disease progression.
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http://dx.doi.org/10.1530/EDM-18-0089DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6215949PMC
October 2018

Quantification of glypican 3, β-catenin and claudin-1 protein expression in hepatoblastoma and paediatric hepatocellular carcinoma by colour deconvolution.

Histopathology 2015 Dec 14;67(6):905-13. Epub 2015 Jul 14.

Department of Pathology and Laboratory Medicine, Children's Hospital Los Angeles, Los Angeles, CA, USA.

Aims: To identify an immunohistochemical panel for paediatric malignant epithelial liver tumours.

Methods And Results: Forty-five hepatoblastomas (HBs), 13 paediatric hepatocellular carcinomas (HCCs) and two hepatocellular malignant neoplasms not otherwise specified (NOS) were chosen for immunohistochemical staining of glypican 3 (GPC3), β-catenin, claudin-1, delta-like protein (DLK), and forkhead box protein G1 (FOXG1). Immunostaining was quantitatively analysed with NIH imagej software coupled with colour deconvolution. Different subtypes of HB and HCC showed distinct staining patterns of GPC3, β-catenin, and claudin-1. Moreover, GPC3, β-catenin and claudin-1 all showed higher expression in classic HCC and embryonal HB than in fetal HB; GPC3 showed complete negativity in small-cell undifferentiated (SCU) HB and fibrolamellar HCC (FLC); β-catenin showed the strongest expression in SCU HB but the weakest expression in FLC. A panel of these three immunomarkers was useful for the diagnosis of hepatocellular malignant neoplasms NOS. The expression of DLK and FOXG1 was inconstant among fetal and embryonal HB and classic HCC.

Conclusions: A panel of GPC3, β-catenin and claudin-1 is helpful for differentiating HB subtypes and distinguishing HB from HCC.
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http://dx.doi.org/10.1111/his.12730DOI Listing
December 2015

Strongyloidiasis hyperinfection in a patient with a history of systemic lupus erythematosus.

Am J Trop Med Hyg 2014 Oct 4;91(4):806-9. Epub 2014 Aug 4.

Department of Pathology, Department of Surgery, and Department of Gastroenterology, Los Angeles County-University of Southern California Medical Center, Los Angeles, California.

Strongyloidiasis is a parasitic disease caused by Strongyloides stercoralis, a nematode predominately endemic to tropical and subtropical regions, such as Southeast Asia. Autoinfection enables the organism to infect the host for extended periods. Symptoms, when present, are non-specific and may initially lead to misdiagnosis, particularly if the patient has additional co-morbid conditions. Immunosuppressive states place patients at risk for the Strongyloides hyperinfection syndrome (SHS), whereby the organism rapidly proliferates and disseminates within the host. Left untreated, SHS is commonly fatal. Unfortunately, the non-specific presentation of strongyloidiasis and the hyperinfection syndrome may lead to delays in diagnosis and treatment. We describe an unusual case of SHS in a 30-year-old man with a long-standing history of systemic lupus erythematosus who underwent a partial colectomy. The diagnosis was rendered on identification of numerous organisms during histologic examination of the colectomy specimen.
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http://dx.doi.org/10.4269/ajtmh.14-0228DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4183409PMC
October 2014

Malignant transformation of a 5-mm gallbladder polyp over 2 years: a case report and review of current literature.

Ultrasound Q 2015 Mar;31(1):66-8

Department of Radiology, University of Southern California, Keck School of Medicine, Los Angeles, CA.

Gallbladder polyps (GBPs) are incidentally seen in 4% to 7% of adults on abdominal ultrasounds. Most GBPs are benign cholesterol polyps, adenomyomatosis, or inflammatory polyps. Currently, cholecystectomy is widely accepted as appropriate care for polyps 10 mm or larger as they present a higher risk for malignancy. However, the management of small polyps smaller than 10 mm has continued to be a dilemma to clinicians and radiologists. Many authors support a nonoperative approach with imaging follow-up for polyps smaller than 10 mm, as most have been shown to be benign. However, small polyps do have the potential to be neoplastic adenomas and become malignant. In this report, we will describe a case of a tiny GBP that subsequently developed into a 20-mm carcinoma over a period of 2 years.
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http://dx.doi.org/10.1097/RUQ.0000000000000094DOI Listing
March 2015