An Approach to Diagnosing Gastrointestinal Stromal Tumors Using Immunohistochemistry of c-kit and PDGFRA with Molecular Analysis

BACKGROUND: Gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumors in the gastrointestinal tract. Recently, many methods for the diagnosis of GIST have been developed including molecular diagnosis. METHODS: We selected 90 cases of GIST that had presented at Kyungpook National University Hospital between 1998 and 2007. Tissue microarrays were made using core areas of tumor tissues. Immunohistochemical staining for c-kit, protein kinase C-theta, and platelet-derived growth factor receptor alpha (PDGFRA) was done. Direct sequencing of hot spot exonal areas for c-kit and PDGFRA were done using extracted DNAs of all 90 paraffin block tissues. RESULTS: Among the 90 cases, 83.3% (75/90) were c-kit positive, 16.6% (15/90) were c-kit negative, 93.3% (84/90) were PDGFRA positive, and 6.6% (6/90) cases were PDGFRA negative. Fifteen cases of c-kit negative GIST included 1 case of PDGFRA negative and 5 cases of PDGFRA negative GIST were ckit positive. The one case in which both c-kit and PDGFRA were negative, showed a c-kit mutation in exon 11. CONCLUSIONS: Combined immunohistochemical staining of c-kit, discovered on GIST 1 (DOG1) and PDGFRA is helpful for the diagnosis of GIST. When all staining tests are negative for immunoreactivity, c-kit mutation analysis for exon 11, 9 should be done. Genotyping of kit and PDGFRA do not need to be examined initially, if it is only for the diagnosis of GIST.

A case of primary effusion lymphoma in a patient with alcoholic liver cirrhosis / 대한내과학회지

Primary effusion lymphoma (PEL) is a distinct clinical and pathologic entity characterized by malignant lymphomatous effusion in body cavities, without a detectable tumor mass. The tumor is usually associated with human herpes virus 8 (HHV-8) infection and occurs principally in immunodeficient patients, most commonly those with human immunodeficiency virus (HIV) infection. We report a rare case of PEL in an elderly patient negative for HHV8 and HIV. The patient had a history of alcoholic liver cirrhosis and presented with abdominal distention. The patient was treated with three courses of chemotherapy. In spite of the generally poor prognosis associated with this disease, our patient is still alive with no malignant lymphomatous cells in the peritoneal cavity 24 months after treatment.

A Clinical Observation of Patients with Hypertrophic Cardiomyopathy and Implantable Cardioverter-Defibrillators

BACKGROUND AND OBJECTIVES: Hypertrophic cardiomyopathy (HCM) is one of the most common heritable cardiac diseases. Patients with HCM are prone to ventricular tachyarrhythmias, and implantable cardioverter-defibrillator (ICD) implantation is recommended in high-risk patients to prevent sudden death. Clinical and tachycardial characteristics in patients with HCM have not been studied systematically. SUBJECTS AND METHODS: Between April 1996 and February 2006, 23 patients with HCM underwent implantation of ICDs. ICDs were indicated for primary prevention in 9 patients and for secondary prevention in 14 patients. Clinical features, follow-up events and intracardiac electrograms were reviewed. RESULTS: During a median follow-up period of 561 days (range 16 to 2,694 days), a total of 51 episodes of ventricular tachycardia (VT) occurred in 6 patients, while only one episode of ventricular fibrillation (VF) was recorded. There were 45 (64.2%) appropriate shocks [30 defibrillation shocks in 5 patients and 15 antitachycardia pacings (ATP) in 2 patients] in 6 patients, and 25 (35.7%) inappropriate shocks in 7 patients. The coupling intervals and VT cycle lengths were highly variable within individual patients. Over-drive acceleration in response to ATP was observed in 1 patient. CONCLUSION: As ventricular tachycardia is the main ventricular tachyarrhythmia in patients with HCM, an empirical ATP setting for VTs appears to be mandatory even in patients without previously documented VT. Based on the analyses of the intracardiac electrograms (presence of overdrive acceleration, variations in coupling intervals and cycle lengths), triggered activity may have an important role in the mechanism of a ventricular tachycardia.

Effects of Divalproex sodium for Visual Cortex Excitability in Migraine: A Study Using Transcranial Magnetic Stimulation

BACKGROUND: The pathophysiology of migraine has not been fully understood. One of the hypotheses is cortical hyperexcitability. Transcranial magnetic stimulation (TMS) is a noninvasive electrophysiologic tool for the investigation of cortical excitability. Divalproex sodium may prevent migraine attacks by increasing the GABA-ergic tone. We examined the phosphene generation using TMS in migraine patients in order to investigate the cortical excitability and its response by valproate prophylaxis. METHODS: We applied TMS to 27 migraineurs and 27 control subjects. TMS was performed by a Magstim Rapid Stimulator connected to a 70 mm figure-of-eight coil to examine the phosphene threshold between migraineurs and controls on primary (V1) and bilateral secondary (V5) visual cortices. Twelve migraine patients completed a one month administration of divalproex sodium 500 mg/day. We compared the phosphene threshold between pre- and post-treatment with devalproex sodium in these patients. RESULTS: The prevalence of the phosphene generation was significantly higher in migraineurs compared with controls in V1 and V5. The phosphene average thresholds were significantly lower in migraineurs compared with controls in V1 and V5. The phosphene average thresholds in the same areas were significantly higher in post-treatment compared with pre-treatment in migraineurs. CONCLUSIONS: The differences of the phosphene threshold in the visual cortex between migraineurs and controls comply with the theory of cortical hyperexcitability for the pathophysiology of migraine. Valproate might play a significant role in the prophylaxis of migraine by decreasing cortical hyperexcitability.

Two Cases of Hypertensive Brainstem Encephalopathy

Hypertensive encephalopathy is a medical disorder, which occurs with sudden increase of blood pressure (BP). The MRI findings of hypertensive encephalopathy are diffuse hyperintensity on T2-weighted images, predominantly within the cortex and subcortical white matter of the parieto-occipital lobe. The brainstem is rarely involved. Diffusion-weighted images do not show any abnormalities. We report two patients with hypertensive encephalopathy whose MRI showed exclusive brainstem involvement. They improved rapidly after BP control.

Two Cases of Hypertensive Brainstem Encephalopathy

Hypertensive encephalopathy is a medical disorder, which occurs with sudden increase of blood pressure (BP). The MRI findings of hypertensive encephalopathy are diffuse hyperintensity on T2-weighted images, predominantly within the cortex and subcortical white matter of the parieto-occipital lobe. The brainstem is rarely involved. Diffusion-weighted images do not show any abnormalities. We report two patients with hypertensive encephalopathy whose MRI showed exclusive brainstem involvement. They improved rapidly after BP control.

A Case of Idiopathic Ocular Neuromyotonia

Ocular neuromyotonia (ONM) is an episodic involuntary contraction of one or more extraocular muscles, resulting from spontaneous neural discharges of ocular motor nerves. Previous radiation therapy to pituitary or other juxtasellar tumor and vascular compressions are the most common reported causes of ONM. We report one unique case of ONM involving the abducens nerve without any other organic brain lesion and prior radiation therapy.