Jong Sang Choi

Multiple gastrointestinal stromal tumors: Clinicopathologic and genetic analysis of 12 patients.

Multiple gastrointestinal stromal tumors (GISTs) are extremely rare and usually associated with type 1 neurofibromatosis and familial GIST. The aim of this study was to investigate the clinical, phenotypic, and genetic characteristics of multiple GISTs to gain insights into their underlying pathogenesis and clinical behavior. Forty-seven paraffin blocks of multiple GISTs from 12 patients were analyzed. Genomic DNA was extracted from the tumor and normal mucosa and mutations for 4 exons of KIT gene and 3 exons of PDGFRA gene were determined. Among 12 patients with multiple GISTs, 5 were sporadic, 2 were familial with germline mutations of KIT gene, and 5 were associated with type 1 neurofibromatosis. All but 1 sporadic and familial multiple GISTs showed mutations of KIT gene shared by the same mutation on each GIST mass within a patient. But in 1 sporadic case, different types of KIT mutations were observed. Two familial multiple GIST cases showed diffuse involvement of the gastrointestinal tract with diffuse hyperplasia of interstitial cell of Cajal. Multiple GISTs associated with type 1 neurofibromatosis were located in the jejunum and harbored no mutations of KIT or PDGFRA. Different types of KIT gene mutation found in our case raise a possibility that recurrence of GISTs within a gastrointestinal tract may have a chance to be a rare occurrence of multiple primary GISTs instead of true recurrence. Multiple GISTs show unique clinical, phenotypic, and genotypic characteristics that are dependent on the particular underlying mechanisms, but the overall prognosis is favorable regardless of the numbers or phenotype of GISTs.

PKCtheta expression in gastrointestinal stromal tumor.

Gastrointestinal stromal tumor is characterized by a gain of function mutation of KIT gene and the expression of c-kit protein, but in 5% of cases, c-kit expression is negative although histological findings of gastrointestinal stromal tumor are most suspicious. The existence of c-kit-negative gastrointestinal stromal tumors points to the need of additional markers for making the diagnosis. In this study, we studied the expression of PKCθ and correlated their expression with other immunohistochemical profiles of gastrointestinal stromal tumors and evaluated their usability as a diagnostic marker. For this purpose, 220 gastrointestinal stromal tumors were immunohistochemically stained for PKCθ, c-kit, CD34, α-smooth muscle actin and S-100 protein. Additionally, genetic studies of KIT and PDGFRA genes were performed using c-kit-negative or PKCθ-negative cases. All the 220 masses were either PKCθ-positive or c-kit-positive. PKCθ was positive in 212 (96%) cases and c-kit was positive in 216 (98%) cases in the cytoplasm of tumor cells with a diffuse staining pattern. Out of 212 PKCθ-positive GISTs, 208 (98%) cases were c-kit-positive, 174 (82%) cases were CD34-positive, 62 (29%) cases were SMA-positive and S-100 protein was positive in 54 cases (26%). Genetic analyses on eight PKCθ-negative cases showed exon 11 mutations of KIT gene in four cases. Two PKCθ-positive and c-kit-negative GISTs showed mutations of PDGFRA gene. Our study shows that PKCθ is a useful marker and it may play a role in the development of gastrointestinal stromal tumors. Together with c-kit, PKCθ immunostaining can be used as an important diagnostic tool in the pathologic diagnosis of gastrointestinal stromal tumors with its high specificity and sensitivity.

PKC θ expression in gastrointestinal stromal tumor

Gastrointestinal stromal tumor is characterized by a gain of function mutation of KIT gene and the expression of c-kit protein, but in 5% of cases, c-kit expression is negative although histological findings of gastrointestinal stromal tumor are most suspicious. The existence of c-kit-negative gastrointestinal stromal tumors points to the need of additional markers for making the diagnosis. In this study, we studied the expression of PKCθ and correlated their expression with other immunohistochemical profiles of gastrointestinal stromal tumors and evaluated their usability as a diagnostic marker. For this purpose, 220 gastrointestinal stromal tumors were immunohistochemically stained for PKCθ, c-kit, CD34, α-smooth muscle actin and S-100 protein. Additionally, genetic studies of KIT and PDGFRA genes were performed using c-kit-negative or PKCθ-negative cases. All the 220 masses were either PKCθ-positive or c-kit-positive. PKCθ was positive in 212 (96%) cases and c-kit was positive in 216 (98%) cases in the cytoplasm of tumor cells with a diffuse staining pattern. Out of 212 PKCθ-positive GISTs, 208 (98%) cases were c-kit-positive, 174 (82%) cases were CD34-positive, 62 (29%) cases were SMA-positive and S-100 protein was positive in 54 cases (26%). Genetic analyses on eight PKCθ-negative cases showed exon 11 mutations of KIT gene in four cases. Two PKCθ-positive and c-kit-negative GISTs showed mutations of PDGFRA gene. Our study shows that PKCθ is a useful marker and it may play a role in the development of gastrointestinal stromal tumors. Together with c-kit, PKCθ immunostaining can be used as an important diagnostic tool in the pathologic diagnosis of gastrointestinal stromal tumors with its high specificity and sensitivity.

Primary pulmonary Ewing's sarcoma/primitive neuroectodermal tumor in a 67-year-old man

Extraskeletal Ewings sarcoma (EES) is a branch of neuroectodermal tumor (PNET), which is very rare soft tissue sarcoma. We report a case of EES/PNET arising is the lung of a 67-yr-old man. Computed tomography, bone scintigraphy, and positron emission tomography confirmed the mass to have a primary pulmonary origin. The mass showed positive reactivity in the Periodic Acid Schiff (PAS) stain and MIC-2 immunoreactivity in immunohistochemical stain. Fluorescence in situ hybridization (FISH) was performed, which revealed an EWSR1 (Ewing sarcoma breakpoint region 1) 22q12 rearrangement. The diagnosis was confirmed both pathologically and genetically. The mass lesion was resected, and the patient is currently undergoing chemotherapy.

Fine needle aspiration cytology of primary pulmonary paraganglioma: A case report

BACKGROUND Primary pulmonary paragangliomas are rare tumors. To our knowledge, there is no prior report on fine needle aspiration cytology (FNAC) in pulmonary paraganglioma. CASE A 34-year-old man presented with an incidentally found solitary pulmonary mass. FNAC showed papillarylike clusters of epithelioid cells with round to oval nuclei, evenly dispersed chromatin, micronucleoli and occasional anisonucleosis. These cytologic features were suggestive of a sclerosing hemangioma or bronchioloalveolar carcinoma. A right lower lobectomy revealed a primary pulmonary paraganglioma. CONCLUSION The possibility of pulmonary paraganglioma should be considered in the differential diagnosis of FNAC showing pseudopapillary clusters of epithelioid cells.

PKCθ expression in gastrointestinal stromal tumor

Gastrointestinal stromal tumor is characterized by a gain of function mutation of KIT gene and the expression of c-kit protein, but in 5% of cases, c-kit expression is negative although histological findings of gastrointestinal stromal tumor are most suspicious. The existence of c-kit-negative gastrointestinal stromal tumors points to the need of additional markers for making the diagnosis. In this study, we studied the expression of PKCθ and correlated their expression with other immunohistochemical profiles of gastrointestinal stromal tumors and evaluated their usability as a diagnostic marker. For this purpose, 220 gastrointestinal stromal tumors were immunohistochemically stained for PKCθ, c-kit, CD34, α-smooth muscle actin and S-100 protein. Additionally, genetic studies of KIT and PDGFRA genes were performed using c-kit-negative or PKCθ-negative cases. All the 220 masses were either PKCθ-positive or c-kit-positive. PKCθ was positive in 212 (96%) cases and c-kit was positive in 216 (98%) cases in the cytoplasm of tumor cells with a diffuse staining pattern. Out of 212 PKCθ-positive GISTs, 208 (98%) cases were c-kit-positive, 174 (82%) cases were CD34-positive, 62 (29%) cases were SMA-positive and S-100 protein was positive in 54 cases (26%). Genetic analyses on eight PKCθ-negative cases showed exon 11 mutations of KIT gene in four cases. Two PKCθ-positive and c-kit-negative GISTs showed mutations of PDGFRA gene. Our study shows that PKCθ is a useful marker and it may play a role in the development of gastrointestinal stromal tumors. Together with c-kit, PKCθ immunostaining can be used as an important diagnostic tool in the pathologic diagnosis of gastrointestinal stromal tumors with its high specificity and sensitivity.

Development of the Korean Academy of Medical Sciences Guideline for Rating Physical Impairment

Systematic and effective welfare for the disabled is possible when there are scientific and objective criteria demonstrating either presence or severity of the impairment. We need our own scientific criteria suitable for our culture and society, since the impairment is influenced by them. In 2007, we established the Developing Committee of Korean Academy of Medical Sciences (KAMS) Guideline for Impairment Rating under KAMS supervision. We included all fixed and permanent physical impairments after a sufficient medical treatment. The impairment should be stable and medically measurable. If not, it should be reevaluated later. We benchmarked the American Medical Association Guides. The KAMS Guideline should be scientific, objective, valid, reasonable and practical. In particular, we tried to secure objectivity. We developed the KAMS Guideline for Impairment Rating.

PKC|[theta]| expression in gastrointestinal stromal tumor

Gastrointestinal stromal tumor is characterized by a gain of function mutation of KIT gene and the expression of c-kit protein, but in 5% of cases, c-kit expression is negative although histological findings of gastrointestinal stromal tumor are most suspicious. The existence of c-kit-negative gastrointestinal stromal tumors points to the need of additional markers for making the diagnosis. In this study, we studied the expression of PKCθ and correlated their expression with other immunohistochemical profiles of gastrointestinal stromal tumors and evaluated their usability as a diagnostic marker. For this purpose, 220 gastrointestinal stromal tumors were immunohistochemically stained for PKCθ, c-kit, CD34, α-smooth muscle actin and S-100 protein. Additionally, genetic studies of KIT and PDGFRA genes were performed using c-kit-negative or PKCθ-negative cases. All the 220 masses were either PKCθ-positive or c-kit-positive. PKCθ was positive in 212 (96%) cases and c-kit was positive in 216 (98%) cases in the cytoplasm of tumor cells with a diffuse staining pattern. Out of 212 PKCθ-positive GISTs, 208 (98%) cases were c-kit-positive, 174 (82%) cases were CD34-positive, 62 (29%) cases were SMA-positive and S-100 protein was positive in 54 cases (26%). Genetic analyses on eight PKCθ-negative cases showed exon 11 mutations of KIT gene in four cases. Two PKCθ-positive and c-kit-negative GISTs showed mutations of PDGFRA gene. Our study shows that PKCθ is a useful marker and it may play a role in the development of gastrointestinal stromal tumors. Together with c-kit, PKCθ immunostaining can be used as an important diagnostic tool in the pathologic diagnosis of gastrointestinal stromal tumors with its high specificity and sensitivity.