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C Choy

Publications and source records attributed to C Choy.

At least 19 recordsLinked to original sources
PubMed2005

Primary anaplastic large cell lymphoma of the pancreas.

Most solid pancreatic tumors are exocrine adenocarcinomas. We presented a patient with primary ALCL of the pancreas masquerading as a carcinoma of the head of pancreas. She was scheduled for a Whipple's operation and the intra-operative frozen section showed anaplastic carcinoma. The proper diagnosis was only derived later with CD30 immunohistochemical study. This carries important implications on the management, as radical surgery is indicated in resectable carcinoma but not for a chemosensitive lymphoma.

Adult↗
PubMed2005

Clinicopathologic features and treatment outcome of mature T-cell and natural killer-cell lymphomas diagnosed according to the World Health Organization classification scheme: a single center experience of 10 years.

BACKGROUND: Data on mature T-cell and natural killer (NK)-cell lymphomas diagnosed with the World Health Organization (WHO) classification scheme are scarce. They are regarded to be more common in Asian populations. METHODS: Consecutive T-cell and NK-cell lymphomas classified according to the WHO scheme within 10 years in a Chinese population were reviewed. RESULTS: There were 148 cases, constituting 16.6% (T-cell, n=90, 10.1%, NK-cell, n=58, 6.5%) of all non-Hodgkin lymphomas in this period. There was a male predominance (male:female = 2.5), young age at diagnosis (median age 50 years, range 8-86) and frequent extranodal presentation. Commonest T-cell lymphomas included anaplastic large cell lymphoma (ALCL, n=25, median age 35 years, nodal 60%, stage I/II 60%), peripheral T-cell lymphoma, unspecified (PTCL, n=24, median age 54 years, nodal 42%, stage I/II 42%), and angioimmunoblastic T-cell lymphoma (AILT, n=19, median age 67 years, nodal 95%, stage I/II 26%). Overall frequencies of T-cell lymphomas were comparable to Western patients. AILT, PTCL and ALCL were aggressive with a poor outcome. NK-cell lymphomas were predominantly extranodal (96%) and aggressive, with a frequency much higher than Western patients. CONCLUSIONS: The apparent high prevalence of T-cell and NK-cell lymphomas in the Chinese was due to more frequent NK-cell but not T-cell lymphomas.

Adolescent↗
PubMed2004

Totally extraperitoneal repair of obturator hernia.

BACKGROUND: One distinct advantage of the 1aparoscopic inguinal hernia repair is the opportunity for clear visualization of the direct, indirect, femoral, and obturator spaces. The surgeon should routinely inspect all of them. Obturator hernia accounts for as few as 0.073% of all hernias, but the mortality rate when it is acutely incarcerated can be as high as 70%. There is only one previous report of a totally extraperitoneal repair for obturator hernia. Five such procedures are described. METHODS: A retrospective review was undertaken to evaluate one surgeon's experience with the totally extraperitoneal repair of obturator hernia over a 4-year period. Four of five cases were completed, and the remaining case was converted to an open procedure. RESULTS: Three hernias were on the right side, and two on the left. One patient presented with an acutely incarcerated obturator hernia and underwent a small bowel resection for strangulated bowel within the obturator space. The other four hernias were found during totally extraperitoneal repair, and the patients were discharged home several hours later. There was one complication, a midline wound infection in the patient with strangulated bowel. It was treated with dressing changes. There were no other complications, and during a follow-up period of 3 to 48 months, there was no recurrence. CONCLUSIONS: The laparoscopic totally extraperitoneal approach allows inspection and repair of direct, indirect, femoral, and obturator hernias. This study found this procedure to be feasible, safe, and highly effective for the diagnosis and repair of obturator hernias.

Adult↗
PubMed2004

Investigating a possible cause of mesh migration during totally extraperitoneal (TEP) repair.

BACKGROUND: In experienced hands, laparoscopic inguinal hernia repair has a low rate of recurrence, but it still can recur, and a number of reasons for this have been identified. In published studies, the majority of such cases seem to result from inadequate dissection leading to missed hernias or suboptimal mesh placement. But even with adequate dissection and proper placement of a sufficiently large mesh, recurrence sometimes happens. A number of investigators have cited mesh migration or dislocation as a possible cause, and this study examined how hip flexion affects the position of newly placed meshes and staples in totally extraperitoneal (TEP) repair of inguinal hernia. METHODS: After completion of the dissection and reduction of discovered hernias, a 15 x 15-cm polypropylene mesh was placed either unilaterally or bilaterally, as indicated. The preperitoneal space then was desufflated. The operating table, in an extended -20 degrees position during surgery, was placed in a 90 degrees position for approximately 15 s. After reinsufflation, the possibility of mesh migration and folding was investigated. Finally, the mesh was stapled, the table again extended and flexed, and the possibility of mesh migration and staple dislodgement investigated once more. RESULTS: The mesh did not migrate or become displaced from any potential hernia area, nor did any of the staples become dislodged. CONCLUSIONS: Concern about mesh migration attributable to patients sitting up immediately after surgery appears to be unfounded, at least according to the findings for the current, small, simulated study group.

Adolescent↗
PubMed2004

Hodgkin's lymphoma in Chinese migrants to British Columbia: a 25-year survey.

BACKGROUND: Compared with the West, Hodgkin's lymphoma in Oriental countries is characterized by a lower incidence rate and a higher proportion of mixed cellularity histology. Both environmental and genetic factors may be involved. PATIENTS AND METHODS: The incidence and pattern of pathology of Hodgkin's lymphoma in the migrant Chinese population (0.4 million) in British Columbia (population 3.2 million) were studied. From a computerized database, all Hodgkin's lymphoma cases diagnosed in British Columbia from 1970 to 1997 were identified. Chinese descent was determined using patient surname by standard methodology and verified from the treatment record or by patient interview. The corresponding figures from the Chinese population in Hong Kong were used for comparison. For incidence rates, the age-specific incidence of Hodgkin's lymphoma in Hong Kong was obtained from the government cancer registry. For comparison of histology subtypes, 200 Hodgkin's lymphoma records from a Hong Kong regional referral center for the same time period were reviewed. Crude and age-standardized incidence rates were calculated by 5-year intervals in terms of age and calendar year, and relative rates were compared between the three populations. RESULTS: From 1970 to 1997, Hodgkin's lymphoma was diagnosed in 34 Chinese patients in BC, with 24 cases diagnosed from 1970 to 1994. Thus, the crude and age-adjusted incidence rates from 1970 to 1994 were 0.91 and 1.14 per 100,000 per year in the British Columbia Chinese migrant population. Within the same period, 1862 cases of Hodgkin's lymphoma were diagnosed in British Columbia, giving a provincial background crude and age-adjusted incidence rates of 5.2 and 4.87 per 100,000 per year. The number of cases in the Hong Kong Chinese population (1970-1994) was 404, giving crude and age-adjusted incidence rates of 0.32 and 0.31 per 100,000 per year, respectively. Corrected for age and calendar year trends, the observed 25-year incidence of Hodgkin's lymphoma in British Columbia Chinese was significantly lower than expected from the British Columbia background population [24 observed versus 71 expected cases; standardized incidence ratio (SIR) = 0.34; 90% confidence interval (CI) 0.24-0.48; P <0.0001]. On the other hand, it is higher than that expected by extrapolating from the Hong Kong Chinese population (24 observed versus 8.5 expected cases; SIR = 2.81; 90% CI 1.94-3.95; P <0.0001). The difference is mainly accounted for by young patients with nodular sclerosis type disease in the migrant population. CONCLUSIONS: Although any conclusion about the impact of migration on Hodgkin's lymphoma incidence and types in the Chinese population must be considered tentative due to the small number of observed cases and confounding variables such as age, changing diagnostic standards and secular trends in Hodgkin's lymphoma rates, our data demonstrate a tendency for the Chinese population of British Columbia to take on a Western pattern of Hodgkin's lymphoma. This observation provides additional evidence that both genetic and environmental influences play a role in the pathogenesis of this lymphoma, and that environmental factors can exert their influence over a relatively short period of time.

Age Factors↗
PubMed2004

Characterization of Salmonella enterica subspecies I genovars by use of microarrays.

Subspecies 1 of Salmonella enterica is responsible for almost all Salmonella infections of warm-blooded animals. Within subspecies 1 there are over 2,300 known serovars that differ in their prevalence and the diseases that they cause in different hosts. Only a few of these serovars are responsible for most Salmonella infections in humans and domestic animals. The gene contents of 79 strains from the most prevalent serovars were profiled by microarray analysis. Strains within the same serovar often differed by the presence and absence of hundreds of genes. Gene contents sometimes differed more within a serovar than between serovars. Groups of strains that share a distinct profile of gene content can be referred to as "genovars" to distinguish them from serovars. Several misassignments within the Salmonella reference B collection were detected by genovar typing and were subsequently confirmed serologically. Just as serology has proved useful for understanding the host range and pathogenic manifestations of Salmonella, genovars are likely to further define previously unrecognized specific features of Salmonella infections.

DNA, Bacterial↗
PubMed2003

Primary B-cell lymphoma and lymphoma-like lesions of the uterine cervix.

We present three patients with atypical lymphoid cells on cervical smear screening, with diffuse large-cell B-cell lymphoma diagnosed by morphology on cervical biopsy. One patient with extensive pelvic disease was treated with chemotherapy and radiotherapy and remained in remission 8 years later. Two patients with presumed stage 1E lesions showed spontaneous regression on repeat cervical biopsy, despite light chain restriction and clonal immunoglobulin gene rearrangement. They are without recurrent malignancy 1 and 5 years after their initial diagnosis. The presence of malignant looking lymphoid cells on cervical smear should be investigated by repeated colposcopic biopsies. The reason for the highly skewed atypical B-cell lymphoproliferation in lymphoma-like lesions of the cervix is unknown. With early stage, nonbulky cervical lymphoma in an otherwise healthy patient, a cone biopsy is advised. A number of these lesions may regress even when clonal populations are detected.

Adult↗
PubMed2003

Treatment of postrenal transplantation lymphoproliferative disease manifesting as plasmacytoma with nonmyeloablative hematopoietic stem cell transplantation from the same kidney donor.

Posttransplantation lymphoproliferative disease (PTLD) presenting as an Epstein-Barr-virus (EBV)-related nasal plasmacytoma developed in a renal-allograft recipient 13 years after transplantation. Systemic dissemination occurred despite immunosuppression withdrawal, surgery, irradiation, and chemotherapy. A nonmyeloablative hematopoietic-stem-cell-transplantation (HSCT) with peripheral blood HSC from the kidney donor was performed. With the onset of graft-versus-host disease, resolution of the systemic disease was demonstrated clinically and molecularly by serial quantification of plasma EBV-DNA. Isolated relapse occurred in the central nervous system (CNS), a known tumour sanctuary site, ultimately leading to death. Nonmyeloablative HSCT might be considered a cellular therapy for PTLD, but possible CNS relapse must be effectively tackled.

Aged↗
PubMed2001

Primary CD56 positive lymphomas of the gastrointestinal tract.

BACKGROUND: Primary CD56 positive lymphoma of the gastrointestinal (GI) tract is rare. Genotypically, these tumors can be classified into natural killer (NK)-like T-cell lymphoma or NK cell lymphoma by the presence or absence of T-cell receptor (TCR) gene rearrangement. However, they have a considerable degree of morphologic and immunophenotypic overlap, making a definitive diagnosis difficult. METHODS: The clinicopathologic features of three patients with primary CD56 positive lymphoma of the small and large bowel are presented. This is followed by a review of the English literature from 1966 to the present. RESULTS: All patients had CD56 positive/CD3epsilon positive disease on paraffin section. Two patients were positive for Epstein-Barr virus-encoded early nuclear RNAs (EBER) according to in situ histochemistry results and were negative for TCR gene rearrangement, consistent with primary NK lymphoma of the GI tract. The other patient was EBER negative with rearranged TCR, consistent with NK-like T-cell lymphoma. There was no clinical or histologic evidence of enteropathy in any of the patients. The major presenting symptoms included fever, weight loss, and intestinal perforation. All patients died between 1 week and 6 months after diagnosis despite undergoing surgery and intensive chemotherapy. CONCLUSIONS: These results, together with a literature review, suggest that primary NK cell lymphoma of the GI tract may be considered a distinct clinicopathologic entity. Both primary NK and NK-like T-cell lymphoma pursue an aggressive clinical course. EBER and TCR gene rearrangement are useful in distinguishing NK cell lymphoma from NK-like T-cell lymphoma, particularly when frozen tissue is not available for immunophenotyping.

Adult↗
PubMed2001

Predictors of positive margins after local excision of ductal carcinoma in situ.

BACKGROUND: This study aimed to examine the association between clinicopathologic parameters and positive margins in women with ductal carcinoma in situ (DCIS) treated by breast-conserving surgery (BCS). METHODS: We retrospectively reviewed the clinical, radiologic, and pathologic data of 100 women who had undergone BCS for DCIS in our center. RESULTS: Sixty-seven percent of patients presented via breast screening and 55% of all cases were diagnosed preoperatively on fine needle aspiration cytology ([FNAC] ie, C5). Overall, 45% of patients had clear margins after initial local excision. Positive margins showed a nonsignificant trend of association with distribution of microcalcifications (MCC), nonconsultant operating surgeon, inconclusive preoperative FNAC, presence of necrosis, and low specimen weight. There was a highly significant association between low grade DCIS (P = 0.003) and incomplete excision. There was no significant association with age, associated invasive focus, morphology of MCC, or with mode of presentation. CONCLUSION: Positive margins after local excision of DCIS are significantly associated with low nuclear grade, and preoperative determination of nuclear grade by core biopsy may have surgical implications.

Biopsy, Needle↗
PubMed2001

Chronic T-cell lymphoproliferative disease expressing natural killer cell receptors: clinicopathological and molecular features.

The frequency and clinicopathological significance of the expression of natural killer cell receptors (NKRs) in T-cell malignancies remain undefined. A 71-year-old man presented with leukocytosis, generalized lymphoadenopathy, and hepatosplenomegaly. Bone marrow and lymph node biopsies showed a T-cell lymphoproliferative disease expressing NKRs (CD2(+), CD3(+), CD4(+), CD5(+), CD7(+), CD8(-), CD56(-), CD94(+), CD158a(+), CD158b(+), CD161(-), p70(-), TCRalphabeta(1), TCRgammadelta(2), TIA-1(-)). An abnormal clone, 46,Y,add(X)(p14),der(1)t(1;6)(p33;p21),t(7;12)(p10;q10), was found on conventional karyotyping. Comparative genomic hybridization confirmed these findings, and showed a deletion of 12p that was not apparent on karyotyping. Clinically, the disease remained indolent and responded transiently to purine analogs but not to intensive chemotherapy. Peripheral T-cell lymphoproliferative disease of CD4(+)alphabeta(1)NKR(+) phenotype is hitherto undescribed. The issues of whether this case was derived from transformation of a rare T-cell subtype or represented aberrant T-cell expression of NK-cell antigens, and the clinicopathologic significance of these T-cell neoplasms warrant further studies.

Anemia↗
PubMed2001

Is MRI more accurate than CT in estimating the real size of adrenal tumours?

BACKGROUND: The size of adrenal tumour plays an important role in the indications for surgical excision of non-functioning adrenal tumours and in selecting the best surgical approach. Computed tomography (CT) has been reported to underestimate the real size of adrenal lesions. The accuracy of magnetic resonance imaging (MRI) in predicting the true tumour size has not been previously investigated. The present retrospective study investigates the accuracy of MRI and CT in the pre-operative determination of true adrenal tumour size. METHODS: The medical records of 65 patients who underwent adrenalectomy for an adrenal mass were reviewed. The size of adrenal tumours as determined by pre-operative MRI and/or CT was compared with the "true" histopathological size. The impact of histological diagnosis on size estimation was also investigated. RESULTS: The median age at diagnosis was 42 years (range 1-82 years) and more patients were female (60%). Five patients had bilateral adrenalectomy, thus giving rise to 70 adrenal specimens. The histopathological size of adrenal tumours ranged from 0.9 to 26 cm with a mean of 5.96 cm and a median of 4.70 cm. For tumours larger than 3 cm, MRI significantly underestimated the real tumour size by 20% (P<0.001). CT also underestimated the size of such tumours by 18.1% (P<0.003). Adrenal phaeochromocytomas were consistently underestimated by both modalities. CONCLUSIONS: MRI and CT significantly underestimated the true size of adrenal tumours larger than 3 cm by 20% and 18%, respectively. Surgeons and endocrinologists should interpret the pre-operative size of adrenal lesions with caution.

Adolescent↗
PubMed2001

Primary hepatic lymphoma.

We report the histologic and CT imaging findings of a patient with primary Burkitt's lymphoma of the liver. She presented with a massive, painless abdominal mass. The tumor responded to chemotherapy but the patient died of neutropenic sepsis.

Aged↗
PubMed2000

Cytogenetic characterization of childhood hepatoblastoma.

We describe the cytogenetic abnormalities in two cases of childhood hepatoblastoma. The first case was of fetal histology with squamous metaplasia, and cytogenetic study showed an add(5)(q31). Although an association between hepatoblastoma and familial adenomatous polyposis is recognized, the breakpoint in this case is distal to 5q21 and most probably does not involve the APC gene at that location. The second case was of macrotrabecular histology, and cytogenetic study showed an unbalanced translocation in the form of der(4)t(1;4)(q12;q34) in a hyperdiploid clone. Including our case, der(4)t(1;4)(q12;q34) has been recognized in four cases of hepatoblastoma, and it may be the first recurrent translocation in this tumor. Understanding the molecular mechanism and clinical significance of this translocation awaits analysis of more cases.

Child, Preschool↗
PubMed2000

Aggressive subcutaneous panniculitis-like T-cell lymphoma: complete remission with fludarabine, mitoxantrone and dexamethasone.

Subcutaneous panniculitis-like T-cell lymphoma (SCPTCL) is a rare cutaneous T-cell lymphoma. The optimal treatment of this disease is undefined. A 36-year-old woman presented with swinging pyrexia, weight loss and disseminated SCPTCL involving her limbs and trunk. Typical histological features of panniculitic infiltration with rimming of fat cells and sparing of the dermis and epidermis were seen. Immunophenotyping confirmed a CD8+ cytotoxic T-cell phenotype. The patient was successfully treated with a combination of fludarabine, mitoxantrone and dexamethasone (FND), and has remained in remission 15 months after cessation of treatment. FND may be an effective regimen for aggressive SCPTCL.

Adult↗
PubMed2000

Is dissection of the internerve tissue during axillary lymphadenectomy for breast cancer necessary?

AIMS: The study evaluates the necessity of dissecting the tissue between the long thoracic and thoracodorsal nerves (internerve tissue) during axillary dissection in breast cancer surgery. By reviewing the lymph node yield and the metastatic rate in the internerve tissue, we examine whether the internerve tissue could be left in situ to minimize the risk of nerve injury. METHODS: A prospective study was conducted on 30 consecutive women undergoing axillary lymphadenectomy for breast cancer. The internerve tissue remaining was excised separately after a routine axillary dissection and was examined by the same pathologist. RESULTS: Twenty (67%) of 30 internerve specimens contained lymph nodes; the internerve nodes were positive for carcinoma in three cases (10%). In one case the lymph node in the internerve tissue was the only metastatic node in the axilla. CONCLUSIONS: There is a significant incidence of lymph nodes (67%) and axillary node metastases (10%) in the tissue lying between the long thoracic and thoracodorsal nerves. Therefore excision of this internerve tissue is strongly recommended in order to optimize decision making regarding adjuvant treatment and oucome in women with operable breast cancer.

Adult↗