Search PubMed⌕ Search

Biomedical subjects

C K Ma

Publications and source records attributed to C K Ma.

At least 37 records · Page 2Linked to original sources
PubMed1993

Immunohistologic characterization of gastrointestinal stromal tumors: a study of 82 cases compared with 11 cases of leiomyomas.

The histogenesis of stromal tumors of the gastrointestinal tract (GIST) is still controversial. Recent immunohistologic and ultrastructural studies have been inconsistent and suggest various cells of origin. In view of these uncertainties, we studied the immuno-profiles of 82 cases of GISTs and 11 cases of stromal tumors that we classified as leiomyomas based on histology. The 82 cases of GIST were subclassified as spindle or epithelioid type stromal tumors based on the predominant pattern and further divided into benign (< 5 cm in size and < 5 mitosis/50 HPF), malignant (> 5 mitosis/50 HPF), and borderline lesions (> 5 cm and < 5 mitosis/50 HPF). A panel of antibodies was used to characterize differentiation toward myogenic cells [pan-muscle actin (HHF-35), alpha-smooth muscle actin (SMA) and desmin], Schwann cells (S-100 protein), enteric glial [(glial fibrillary acidic protein (GFAP)], and nerve cells (neurofilaments). All leiomyomas were strongly positive for the three muscle markers. Of the 82 GISTs, only four cases (5%) were positive for desmin. However, 63% (52 cases) were positive with anti-pan-muscle actins and 39% (32 cases) were positive with anti-SMA. Compared with gastric tumors, the positivity rates were much higher for small bowel tumors. Seventy-nine cases (96%) were positive for vimentin, only five cases and two cases were focally and weakly reactive for S-100 protein and GFAP respectively, and none stained for neurofilaments.(ABSTRACT TRUNCATED AT 250 WORDS)

Actins↗
PubMed1992

Immunohistochemical characterization of atypical fibroxanthoma and dermatofibrosarcoma protuberans.

Atypical fibroxanthoma (AFX) and dermatofibrosarcoma protuberans (DFSP) have generated undue interest regarding their histogenesis, biological behavior, and differentiation from other forms of spindle cell tumors of the skin, including spindle cell squamous carcinomas and desmoplastic melanomas. To identify characteristic immunophenotypes, 12 AFXs and 15 DFSPs were examined with a panel of antibodies against cytokeratin; vimentin; desmin; proteolytic enzymes (alpha-1-antitrypsin and alpha-1-antichymotrypsin); melanoma-associated antigens defined by HMB-45, HMB-50, and NKI/C3; muscle-specific actin (HHF-35); and S-100 protein. The staining patterns of these two tumors were nearly identical. All cases tested negative for cytokeratin, desmin, and S-100 protein and strongly positive for vimentin. Six (50%) AFXs and 12 (80%) DFSPs tested focally positive for muscle-specific actin. None of the cases were reactive with melanoma antibodies HMB-45 and HMB-50; NKI/C3 strongly stained 26 of 27 tumors. Compared to HMB-45 and HMB-50, NKI/C3 cross-reacted with nonmelanocytic neoplasms. Two AFXs stained for alpha-1-antitrypsin and alpha-1-antichymotrypsin. This study confirms (1) the immunophenotypic similarity of AFX and DFSP, (2) the presence of myofibroblastic differentiation in both tumors, as reflected by HHF-35 staining, and (3) that AFX and DFSP are easily distinguished from spindle cell squamous carcinoma and desmoplastic melanoma by the absence of cytokeratin, HMB-45, and HMB-50 staining.

Adult↗
PubMed1992

Increased density of Helicobacter pylori on antral biopsy is associated with severity of acute and chronic inflammation and likelihood of duodenal ulceration.

An increased risk of ulcers and severity of inflammation with increased degree of Helicobacter pylori (HP) infection (biological gradient) would support the hypothesis that HP causes ulcers. A blinded pathologist evaluated antral biopsies obtained at endoscopy in 903 patients. The level of HP infection was assessed on Warthin Starry stain, and the severity of acute and chronic inflammation on hematoxylin and eosin graded from 0 to 3. The presence of duodenal ulcers was associated with increasing HP density (grade 0, 6%; grade 1, 16%; grade 2, 19%; and grade 3, 27%) (p less than 0.0001, Wilcoxon rank sum test). Only a weak association between HP and gastric ulcers was detected (p = 0.06, Wilcoxon rank sum test), and this association diminished after adjusting for other risk factors. An increased acute and chronic inflammatory response correlated with increasing HP concentration (p less than 0.0001, Cochran-Mantel-Haenszel correlation statistic. The presence of this biologic gradient supports the hypothesis that HP is pathogenic in duodenal ulcers and in acute and chronic gastritis.

Acute Disease↗
PubMed1991

Helicobacter pylori-negative duodenal ulcer.

UNLABELLED: PURPOSE PATIENTS AND METHODS: Helicobacter pylori (HP) is present in more than 90% of duodenal ulcers (DUs). To investigate the pathophysiology in those patients with DU who are HP-negative compared with those who are HP-positive, we interviewed consecutive patients prior to endoscopy regarding factors often associated with ulcer disease. At esophagogastroduodenoscopy, antral biopsy specimens were obtained for urease test, culture, and Warthin Starry staining for HP in all patients with DU who did not have active bleeding. RESULTS: Compared with HP-positive patients who had DU, HP-negative patients with DU were more likely to be aspirin users and less likely to have had prior ulcers. HP-positive patients with DU had more severe antral inflammation than HP-negative patients. Whites were more likely to be HP-negative than blacks. HP-negative patients with DU most commonly presented with bleeding, whereas HP-positive patients with DU presented with pain. CONCLUSIONS: Our findings suggest a different mechanism for DUs in patients who are HP-positive versus those who are HP-negative, and this difference might have a bearing on treatment. The absence of HP should lead to a more thorough search for nonsteroidal anti-inflammatory drug/aspirin use, Zollinger-Ellison syndrome, and other potential causes of DUs.

Aspirin↗
PubMed1991

Collagenous colitis: report of nine cases and review of the literature.

Collagenous colitis is characterized clinically by chronic watery diarrhea and pathologically by a distinctive band of collagen deposited below the colonic epithelium and an inflammatory cell infiltrate of the lamina propria. Since 1976, more than 100 cases have been described. We report an additional nine cases occurring in five women and four men ranging in age from 18 to 80 years. Diarrhea was present before diagnosis for 2 to 4 months in four cases and for 1 to 25 years in another four cases. One patient did not have diarrhea. Results of radiologic and stool studies were normal in all cases. All patients had flexible sigmoidoscopy or colonoscopy. Microscopic examination of biopsy material was interpreted as characteristic of collagenous colitis. Two cases resolved with psyllium mucilloid therapy alone. Of the five patients treated with azulfidine, three had marked improvement, one had partial response, and one had no change.

Adolescent↗
PubMed1990

Diversion colitis: a clinicopathologic study of 21 cases.

Inflammation occurring in a defunctionalized portion of bowel, following either ileostomy or colostomy, has long been recognized by endoscopists. However, little has been written about this entity, particularly the histopathologic changes. Glotzer et al in 1981 described 10 cases, and coined the term "diversion colitis". We studied 21 patients without previous history of inflammatory bowel disease who, for reasons including perforated diverticulitis, carcinoma, or trauma, had loop colostomies or Hartmann's procedure performed. Many of these patients became symptomatic with complaints related to the defunctionalized bowel, including rectal discomfort, pain, discharge, and bleeding. Nineteen patients had endoscopic examinations, which revealed a variety of findings including mucous plugs, friability, petechia, erythema, ulcers, exudate, and nodules or polyps. All except one case had tissue from the excluded portions of bowel available for pathologic examination. Most displayed nonspecific changes with mild-to-moderate lymphoplasmacytic infiltrates in the lamina propria, mild architectural alterations of the crypts, and slight decrease in crypt numbers. Ulceration, cryptitis, and crypt abscesses simulating ulcerative colitis were uncommon findings and were observed almost exclusively in more severe cases. Granulomas were observed in two cases, raising the possibility of Crohn's disease.

Adult↗
PubMed1990

Hemangiomas with localized nodular proliferation of the liver. A suggestion on the pathogenesis of focal nodular hyperplasia.

Multiple cavernous hemangiomas circumscribed by focal regenerative nodules of hepatocytes were incidental findings at the autopsy of two elderly men. Neither patient was on steroids or had venous thrombosis. The lesions were not typical for other nodular proliferations of the liver, such as focal nodular hyperplasia, nodular regenerative hyperplasia, or liver cell adenoma, and they have not been previously reported. We also explore the roles of vascular malformation, oral contraceptives, and thrombosis in the pathogenesis of localized nodular proliferation of the liver.

Aged↗
PubMed1990

Peritoneal mesothelioma: an unusual cause of esophageal achalasia.

Secondary esophageal achalasia due to malignancy is a rare condition; only 53 such cases have been reported to date. Sixty-two percent of the cases were due to gastric adenocarcinoma. Mesothelioma of the peritoneum is an uncommon neoplasm. The usual presenting symptoms are abdominal pain, abdominal mass, or abdominal distention. The patient we are reporting had peritoneal mesothelioma which presented with dysphagia and weight loss, in addition to the radiological and manometric picture of achalasia. Secondary achalasia was suspected clinically, and was confirmed by computed tomography and laparotomy. The diagnosis of peritoneal mesothelioma was made only by histopathological examination. We are not aware of any other report documenting the association of peritoneal mesothelioma and achalasia.

Aged↗
PubMed1990

Flow cytometric DNA and clinicopathologic analysis of Dukes' A&B colonic adenocarcinomas: a retrospective study.

We retrospectively evaluated DNA content flow cytometrically in a series of 124 colonic adenocarcinomas selected for uniformity of stage (A and B), anatomical location (right or transverse colon), and treatment (surgical only) in order to precisely define the significance of ploidy. Aneuploid populations were detected in 43% overall and more commonly with advancing stage (31% Stage A versus 45% Stage B), although this trend did not reach statistical significance (P = 0.16). Overall, as well as stage corrected, 5-yr patient survival was higher for patients with diploid range tumors, but not significantly (71% diploid range versus 60% aneuploid, P = 0.19). Dukes' stage, in contrast, was strongly predictive for 5-yr survival (89% Stage A versus 61% Stage B, P less than or equal to 0.005). Abnormal DNA content was significantly associated with increased patient age (P = 0.02) and presence of angiolymphatic invasion (P = 0.013) but not tumor grade (P = greater than or equal to 0.10). We conclude that flow cytometrically determined abnormal DNA content is weakly related to pathologic features of biologic aggressiveness in colonic adenocarcinoma and is less predictive of patient outcome than conventional Duke's stage.

Adenocarcinoma↗
PubMed1989

Submucosal arterial malformation of the colon with massive hemorrhage. Report of a case.

The case of a 60-year-old man with massive lower intestinal bleeding, secondary to erosion of an abnormally large submucosal muscular artery in the ascending colon, is reported. The bleeding site was localized by angiography. The clinicopathologic presentation of this case is identical to Dieulafoy's disease, which occurs almost exclusively in the stomach. Three similar patients with lesions also located in the ascending colon have been reported in the English medical literature.

Arteries↗
PubMed1989

Histopathologic parameters and DNA analysis in colorectal adenocarcinomas.

Human colon adenocarcinomas have histological parameters that are clearly associated with prognosis. These include tumor grade, pattern of invasion, presence of lymphocytes, and vascular involvement by tumor. The latter remains controversial with respect to the relative importance of intramural and extramural vascular involvement. Some studies show a poor prognosis for intramural invasion of capillary size vascular channels by tumor. On the other hand, when veins are involved by tumor, the presence of tumor in large extramural veins appears to have a much more ominous effect than intramural tumor involvement of small veins. The results of DNA analysis of colorectal adenocarcinomas varied greatly depending on study methodology but several important points can be summarized: (1) higher stage tumors have a greater proportion of aneuploid tumors; (2) aneuploid tumors tend to have a higher growth rate (SPF) and poorer survival than diploid tumors; and (3) aneuploid tumors are associated with histological parameters indicative of a poor prognosis such as vascular invasion, but ploidy is not related to tumor grade. One of the major problems in drawing firm conclusions about the relationship of flow cytometric DNA measurements to prognosis is great variability among the reported studies. The types of variation appear to fall into two major categories: patient selection and technical problems. The former are especially relevant in retrospective studies in which there is poor patient definition (site, grade, stage, and other standard tumor definitions) and a bias for selecting early stage tumors which have improved survivals. The latter includes a spectrum of technical problems inherent in this widely but not necessarily uniformly applied laboratory procedure. This is particularly true for DNA analysis of nuclei removed from paraffin tissue blocks. For the most part, quality control measurements including cell yields, the efficiency of extraction or disaggregation of aneuploid cells, exclusion of non-neoplastic cells, and other features characteristic of the scientific method are seldom included in studies of DNA analysis of solid tumors. Hopefully, a consensus regarding optimum technical and analytic methods will evolve, followed by the careful definition of human colon cancer cohorts. The importance of further studies is suggested by the results of this review which indicated that the presence of an aneuploid cell population is associated with a less favorable prognosis for all colorectal tumors.

Adenocarcinoma↗
PubMed1989

Papillary cystadenocarcinoma of the bile ducts resulting in hemobilia.

Cystadenocarcinoma is a rare tumor of the intrahepatic and a very rare tumor of the extrahepatic biliary system. In the reported cases, abdominal swelling is the most common presenting symptom, followed by right upper quadrant mass. Melena was the initial presenting symptom in the present case. Bleeding into the second part of the duodenum was observed only during the third diagnostic esophagogastroduodenoscopy. Hemobilia was suspected because of abnormal liver enzymes and a mass in the left lobe of the liver on computerized tomography. At laparotomy, we suspected that the mass was a hemangioma. Cystadenocarcinoma diagnosis was made only by histopathological examination.

Aged↗
PubMed1987

Gastric cancer in San Marinese and their first degree relatives in San Marino and the United States. Gastroscopic biopsy as an epidemiological tool.

The Republic of San Marino, a small, 23-square mile, independent country near the Adriatic Coast within Italy, has been noted to have a high incidence of gastric cancer in its 22,000 population (9% of all deaths from 1969-1983 with 33% of all cancer deaths attributed to gastric cancer). Gastroscopic biopsy studies on 284 first degree relatives of San Marinese gastric cancer patients in the Republic of San Marino and in Detroit, where 2,000-2,500 San Marinese reside, have allowed detection of six gastric malignancies. Intestinal metaplasia of gastric mucosa was found in 16 (52%) of 31 Detroit first degree relatives and 51 (36%) of 143 San Marino first degree relatives. Gastroscopy provides an important tool not only for the early detection of gastric cancer in populations of high risk (such as that of San Marino), but also for providing clues to the genetic and environmental factors in gastric neoplasia.

Aged↗
PubMed1987

Pathologic findings in adrenoleukodystrophy heterozygotes.

Two women, heterozygous for X-linked adrenoleukodystrophy, contained striated adrenocortical cells without inflammation and central nervous system demyelinative lesions. Only one was symptomatic neurologically; neither exhibited hypoadrenalism. These findings further document the variability of adrenoleukodystrophy heterozygotes and provide evidence that the major pathologic differences between hemizygote and heterozygote are quantitative in nature.

Adrenal Glands↗
PubMed1986

Hepatocellular adenoma of the placenta.

A unique primary placental tumor, designated "hepatocellular adenoma of the placenta," is reported. The tumor was composed of cells resembling fetal hepatocytes. The hepatocellular nature of the tumor cells was supported by ultrastructural and immunohistochemical findings. Histogenetically, this tumor most likely represents a highly specialized monodermal teratoma.

Adult↗
PubMed1985

Clear cell myeloma.

We report a case of clear cell myeloma misinterpreted at initial biopsy as liposarcoma. The patient had lytic skeletal lesions and monoclonal IgA, kappa, serum immunoglobulin. The tumor cells contained cytoplasmic vacuoles that produced a clear histologic appearance. The light-microscopic and ultrastructural findings are compared with those of other cases of lymphoplasmacytic disorders with prominent cytoplasmic inclusions.

Aged↗