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W Cheuk

Publications and source records attributed to W Cheuk.

At least 19 recordsLinked to original sources
PubMed2005

Inv(1)(p22q25) in chronic myeloproliferative disease: constitutional or clonal defect?

Pericentric inversion of chromosome 1 is uncommon in chronic myeloproliferative disease. We report the occurrence of an isolated inv(1)(p22q25) in two patients with BCR/ABL-negative chronic myeloproliferative disease. The inv(1) is an acquired clonal abnormality in one patient and a constitutional defect in the other. To our knowledge, this is the first report on the occurrence of inv(1)(p22q25) in hematolymphoid malignancies.

Aged↗
PubMed2005

Solitary superficial angiomyxoma in the eyelid.

PURPOSE: To report the clinicopathologic features of a solitary superficial angiomyxoma arising in the eyelid. DESIGN: Case report. METHODS: A retrospective review of the clinical and pathologic features of a patient with solitary superficial angiomyxoma in the eyelid. RESULTS: A 47-year-old male presented with a right upper lid mass for 6 months. Excisional biopsy was performed, and microscopic examination revealed a tumor comprising loose spindle or stellate-shaped cells in myxoid stroma sprinkled with small numbers of neutrophils. The tumor cells were negative for smooth muscle actin, desmin, S-100 protein, and CD34 on immunostaining. CONCLUSIONS: Ophthalmologists should be aware of superficial angiomyxoma as a rare cutaneous tumor with a tendency for local recurrence. Multiple lesions and occurrence in the external ear can be associated with the Carney's complex.

Biomarkers, Tumor↗
PubMed2004

Subcellular localization of immunohistochemical signals: knowledge of the ultrastructural or biologic features of the antigens helps predict the signal localization and proper interpretation of immunostains.

In the literature, sufficient attention has not been paid to the precise subcellular localization of immunohistochemical signals, the knowledge of which is essential for proper interpretation of immunostains and distinction of genuine staining from biotin-associated or other nonspecific stainings. The subcellular localization of the signals can in fact be easily deduced from the known biologic or ultrastructural characteristics of the antigens. Extracellular antigens obviously are located in the extracellular compartment. Cellular antigens fall into 3 major groups: membranous, nuclear, and cytoplasmic. Membranous antigens include cell adhesion molecules (such as E-cadherin, N-CAM), cell surface/transmembrane receptors and proteins (such as tyrosine kinase receptors, most leukocyte antigens, CD10, CEA), and molecules linking surface molecules to cytoskeleton (such as beta-catenin, dystrophin). Nuclear antigens include cell cycle-associated proteins (such as cyclins, p16, Ki-67), nuclear enzymes (such as TdT), transcription factors (such as TTF-1, CDX-2, myogenin, PAX-5), tumor suppressor gene products (such as p53, p63, WT1, Rb), steroid hormone receptors (such as ER, PR), calcium-binding proteins (such as S-100 protein, calretinin), and some viral proteins (such as CMV, herpes). Cytoplasmic antigens can take up a granular pattern due to localization in organelles, granules, or secretory vesicles (such as chromogranin, hormones, lysozyme, HMB-45), fibrillary pattern attributable to the filamentous nature of the molecules (intermediate filaments and microfilaments), or diffuse or patchy pattern due to localization in the cytosol or large vesicles (such as myoglobin, albumin, thyroglobulin). Aberrant localization of the molecules, when present, can provide important insight into disease processes and aid in their diagnosis, such as loss of membranous E-cadherin expression in lobular breast carcinoma, aberrant nuclear localization of beta-catenin in colorectal adenocarcinoma, pattern of ALK staining in anaplastic large cell lymphoma correlating with the different types of chromosomal translocations, presence of additional cytoplasmic CD10 staining in the enterocytes indicative of microvillous inclusion disease, and "reversed" staining for EMA in micropapillary mammary carcinoma.

Animals↗
PubMed2002

Epstein-Barr virus-associated smooth muscle tumour: a distinctive mesenchymal tumour of immunocompromised individuals.

immunosuppressed patients are predisposed to the development of smooth muscle tumours which show near consistent association with Epstein-Barr virus (EBV). This report describes a 37-year-old patient with acquired immunodeficiency syndrome who initially presented with two masses in the liver. Image-guided core biopsy revealed a spindle cell tumour with histological and immunological features of smooth muscle neoplasm which was shown by in situ hybridisation for EBV early RNAs to be EBV-associated. The literature on this uncommon entity is critically reviewed and the differential diagnosis is also discussed.

Acquired Immunodeficiency Syndrome↗
PubMed2002

Cotyledonoid leiomyoma: a benign uterine tumor with alarming gross appearance.

Cotyledonoid leiomyoma or "grapelike" leiomyoma is a very rare tumor among the ever-expanding repertoire of growth variants described in benign uterine leiomyoma. We report a case of cotyledonoid leiomyoma in a 55-year-old woman who presented with menorrhagia and uterine prolapse. A large multinodular fungating tumor adhering to the right posterolateral wall of the uterus and extending to the broad ligament was discovered at vaginal hysterectomy. With a provisional diagnosis of sarcoma, total hysterectomy and bilateral salpingo-oophorectomy were performed. Postoperatively, the patient was well with no evidence of recurrence at 14 months. Pathologic examination revealed a 10-cm, red-brown tumor that comprised multiple bulbous processes protruding over the uterine surface, in continuity with a dissecting intramyometrial component. It was composed of fascicles and nodules of bland-looking smooth muscle cells with prominent perinodular hydropic degeneration. Coagulative necrosis, mitoses, and nuclear atypia were absent. Cotyledonoid leiomyoma apparently results from a combination of several uncommon growth patterns operating together, including subserosal growth, dissecting growth, and perinodular hydropic degeneration. Increased awareness of this grossly alarming variant of benign uterine leiomyoma can help avoid overtreatment.

Female↗
PubMed2001

CYP2D6 genotyping with oligonucleotide microarrays and nortriptyline concentrations in geriatric depression.

Recent advances in oligonucleotide microarray technology ("gene chips") permit rapid screening for DNA sequence variation. The CYP2D6 gene encodes debrisoquine hydroxylase, which metabolizes the antidepressant nortriptyline and other psychotropic medications. Nortriptyline plasma concentrations were obtained after at least three weeks of treatment in 36 geriatric patients with major depression who were taking a mean of 8.6 other medications besides nortriptyline. Oligonucleotide microarrays were used to detect 16 CYP2D6 alleles that affect debrisoquine hydroxylase activity. Subjects carrying alleles encoding impaired debrisoquine hydroxylase activity had significantly greater nortriptyline concentrations and lower nortriptyline doses than did other subjects. Significant correlations were found between the numbers of alleles encoding decreased metabolism and nortriptyline plasma concentration, nortriptyline dose, and nortriptyline plasma concentration standardized for dose, indicating a gene dosage effect. These results demonstrate that CYP2D6 genotyping on a microarray platform can be used to predict plasma antidepressant concentrations despite advanced patient age and numerous concurrent medications.

Aged↗
PubMed2001

Timely topic: anaplastic lymphoma kinase (ALK) spreads its influence.

Anaplastic lymphoma kinase (ALK) is normally not expressed in human tissues except selected sites in the nervous system. Its expression and constitutive activation as a result of a chromosomal translocation involving 2p23 plays a pivotal role in the genesis of anaplastic large cell lymphoma. ALK expression has been instrumental in defining a homogeneous subset from the category of anaplastic large cell lymphoma, characterised by occurrence in young patients, primary systemic presentation, favorable prognosis, a broad morphological spectrum, nuclear and/or cytoplasmic immunostaining for ALK protein, and a number of possible fusion partner genes such as NPM, ATIC, TFG, TPM3 and CLTCL. Recently ALK has been implicated in the genesis of another tumour type, the inflammatory myofibroblastic tumours. The ALK-positive examples occur in children and young adults, involving a variety of sites, such as the abdomen, mesentery, liver, bladder, mediastinum, lung and bone. The partner genes identified in some cases are TPM3 (tropomyosin 3) and TPM4 (tropomyosin 4). These molecular findings also further support the neoplastic nature of at least a subset of inflammatory myofibroblastic tumours.

Anaplastic Lymphoma Kinase↗
PubMed2001

Inflammatory pseudotumor-like follicular dendritic cell tumor: a distinctive low-grade malignant intra-abdominal neoplasm with consistent Epstein-Barr virus association.

Follicular dendritic cell (FDC) tumors are uncommon neoplasms that can involve lymph nodes or extranodal sites. They can exhibit a broad spectrum of histologic appearances and behavior, but the intra-abdominal ones usually pursue an aggressive course. The purpose of this study was to characterize a distinctive variant of FDC tumor morphologically mimicking inflammatory pseudotumor through analysis of the clinicopathologic features of 11 cases. The patients included 10 women and one man (age range, 19-61 years; median age, 40 years) who presented with abdominal discomfort or pain. Six patients had systemic symptoms such as marked weight loss, fever, or malaise. All tumors occurred in intra-abdominal sites: liver (n = 7), spleen (n = 3), and peripancreatic region (n = 1). Of the nine patients with follow-up data, six were alive and well, one developed recurrence at 9 years, and two had repeated recurrences over many years. Grossly, the tumors were usually solitary and fleshy, punctuated by areas of hemorrhage and necrosis. Histologically, in a background of abundant lymphocytes and plasma cells were dispersed spindle or ovoid cells with vesicular nuclei and distinct nucleoli. The degree of nuclear atypia was variable, and some nuclei could be grotesque or resemble Reed-Sternberg cells. Focally, spindle cell fascicles could be formed. The atypical cells were immunoreactive for FDC markers such as CD21/CD35, CD23, and CNA.42. In situ hybridization for Epstein-Barr virus (EBV)-encoded RNA was positive in all cases, remarkably highlighting the spindle cells and their atypia. EBV-latent membrane protein-1 was expressed commonly, albeit often focally and weakly. Therefore, inflammatory pseudotumor-like FDC tumor represents a distinctive variant of FDC tumor that differs from conventional FDC tumor in the following aspects: marked female predominance; selective localization in intra-abdominal sites, especially the liver and spleen; frequent presence of systemic symptoms; indolent behavior despite an intra-abdominal location; dispersed distribution of tumor cells and prominent lymphoplasmacytic infiltration; and consistent association with EBV.

Abdominal Neoplasms↗
PubMed2001

Anaplastic lymphoma kinase expression in inflammatory pseudotumors.

Anaplastic lymphoma kinase (ALK), a hallmark of anaplastic large cell lymphoma, has recently been implicated in the genesis of some inflammatory pseudotumors (inflammatory myofibroblastic tumors) in children and young adults. The aim of this study was to determine the frequency of its expression among inflammatory pseudotumors, and to characterize the clinicopathologic features of the positive cases. Sixty-one cases of inflammatory pseudotumors were retrieved from the surgical pathology archives and consultation files. Paraffin sections were immunostained with the antibody ALK1. The patients ranged in age from 0.5 to 79 years (median age, 50 years), with 10 patients (16.4%) younger than 20 years. Five cases (8.2%) were ALK+, including two of six urogenital inflammatory myofibroblastic tumors, none of eight pulmonary inflammatory pseudotumors, three (one adrenal, one small bowel, one liver) of 31 extrapulmonary inflammatory pseudotumors, none of nine hepatic/splenic inflammatory pseudotumors expressing follicular dendritic cell markers and harboring Epstein-Barr virus, and none of seven inflammatory pseudotumors of the lymph node. When only those patients 40 years or younger were considered, the ALK positivity rate became 21.7% (five of 23). All five ALK+ cases occurred in young patients aged 0.5 to 37 years, who were alive and well at 3.5 to 17 years. The tumors exhibited a spectrum of histologic features typical of inflammatory pseudotumors/myofibroblastic tumors, but there was at least focal nuclear atypia. Immunostaining for ALK produced fibrillary or granular cytoplasmic staining in the neoplastic cells, sometimes with cell membrane accentuation. This study confirms that ALK is implicated in a proportion of inflammatory pseudotumors, and is generally associated with a favorable outcome. The results also support the heterogeneity of inflammatory pseudotumors, with the follicular dendritic cell/Epstein-Barr virus-positive cases and those occurring in lymph nodes representing different biologic entities.

Adolescent↗
PubMed2001

Primary histiocytic lymphoma of the central nervous system: a neoplasm frequently overshadowed by a prominent inflammatory component.

True histiocytic lymphoma, as defined by strict criteria, is a very rare neoplasm. We describe three cases occurring as primary tumors in the central nervous system. The patients, two females and one male, ranged in age from 11 to 69 years. The tumors involved the brain in two cases and spinal cord in one, with a size ranging from 7 to 17 mm. Two patients died at 4 months and 8 months, respectively, and one was alive with disease at 5 months. Pathologically, the tumors comprised groups and sheets of noncohesive large cells with pleomorphic vesicular nuclei, distinct nucleoli, and abundant eosinophilic cytoplasm. A dense inflammatory infiltrate consisting of neutrophils, lymphocytes, plasma cells, and histiocytes was present, with multiple foci of necrosis and abscess formation. All three cases demonstrated an identical immunophenotype: positive for CD68 and lysozyme; focally positive for S-100 protein, CD45RB, and CD4; and negative for CD3, CD20, CD21/CD35, CD1a, CD30, ALK1, myeloperoxidase, glial fibrillary acidic protein, and cytokeratin. The proliferative index ranged from 20% to 35%. Ultrastructural examination further confirmed the histiocytic nature of the tumor cells, characterized by irregularly folded or multisegmented nuclei and abundant cytoplasm containing lysosomes; Birbeck granules, interdigitating cell processes, and cell junctions were not found. Although the presence of abundant inflammatory cells could obscure the neoplastic histiocytes, making the distinction from inflammatory conditions difficult, awareness of this unusual histologic feature and the invariable finding of pleomorphic cells in some areas of the lesion permit the correct diagnosis to be made.

Adult↗
PubMed2001

Immunostaining for thyroid transcription factor 1 and cytokeratin 20 aids the distinction of small cell carcinoma from Merkel cell carcinoma, but not pulmonary from extrapulmonary small cell carcinomas.

OBJECTIVE: To study the expression of thyroid transcription factor 1 (TTF-1) and cytokeratin 20 (CK20) in pulmonary small cell carcinomas, extrapulmonary small cell carcinomas, and Merkel cell carcinomas, and thereby determine whether these markers are helpful in distinguishing these 3 groups of small cell neuroendocrine carcinomas. MATERIALS AND METHODS: Immunostaining for TTF-1 and CK20 was performed in 102 cases of small cell carcinoma (pulmonary, 52; extrapulmonary, 50) and 23 cases of Merkel cell carcinoma. The results for the 3 groups were compared. RESULTS: Thyroid transcription factor 1 was expressed in 82.7% of pulmonary small cell carcinomas, 42.0% of extrapulmonary small cell carcinomas (range, 33.3--53.3% for the various sites), and 0% of Merkel cell carcinomas. Cytokeratin 20 staining was consistently negative in pulmonary small cell carcinomas, and positive in 4.0% of extrapulmonary small cell carcinomas and 100% of Merkel cell carcinomas. CONCLUSIONS: Immunostaining for TTF-1, especially when combined with immunostaining for CK20, can aid in the distinction between Merkel cell carcinoma and small cell carcinoma (both pulmonary and extrapulmonary). However, in individual cases, these markers cannot be used to distinguish between pulmonary and extrapulmonary small cell carcinomas due to the extensive overlap in immunophenotypes.

Carcinoma, Merkel Cell↗
PubMed2001

Clear cell variant of fibrolamellar carcinoma of the liver.

Fibrolamellar carcinoma of the liver is a distinctive variant of hepatocellular carcinoma characterized histologically by trabeculae of oncocytic cells with intervening lamellae of collagen fibers. We describe a case with a prominent component of clear cells, a feature not previously recognized in this tumor type. The patient was a 59-year-old woman incidentally found to have a solitary liver tumor, measuring 5 cm. Pathologic examination revealed a circumscribed, firm, tan tumor with peculiar concentric streaks. Oncocytic cells and clear cells were arranged in trabeculae separated by lamellae of collagen or sinusoids. The clear cells possessed abundant finely reticulated clear cytoplasm, which was highlighted by trichrome stain and immunostaining with antimitochondria antibody. Ultrastructurally, the cytoplasm of the clear cells was packed with empty membrane-bound vesicles that occasionally contained short cristae. The features suggested that the clear cell change resulted from ballooning and rarefactive changes of mitochondria. Clear cell fibrolamellar carcinoma should not be confused with conventional clear cell hepatocellular carcinoma, since the former is associated with a more favorable prognosis.

Carcinoma, Hepatocellular↗
PubMed2000

Psychological stress and the subsequent appearance of new brain MRI lesions in MS.

OBJECTIVE: To examine the relationship between stressful life events and psychological distress, and the subsequent development of gadolinium-enhancing (Gd+) brain lesions. BACKGROUND: It has long been speculated that stressful life events and psychological distress are associated with disease exacerbation in MS. This is the first prospective longitudinal study of the relationship between stressful life events, psychological distress, and disease activity as measured by Gd+ brain MRI. METHODS: Thirty-six patients (mean age, 44.4 years; 22 women, 14 men) with relapsing forms of MS were assessed once every 4 weeks for 28 to 100 weeks. Assessments included Gd+ MRI, the Social Readjustment Rating Scale (SRRS), the Hassles Scale, and the Profile of Mood States. The SRRS was altered in the following manner: 1) three items that confounded with MS were eliminated, 2) endorsed items were rated for intensity, and 3) the scale was divided into three subscales: major negative events, conflict and disruption in routine, and positive life events. Data were analyzed using mixed-effects logistic regression to account for intrasubject correlations. Stress and distress measures were used to predict concurrent and future MRI activity. RESULTS: For the total sample of patients, increased conflict and disruption in routine was followed by increased odds of developing new Gd+ brain lesions 8 weeks later (odds ratio, 1.64; p = 0.00083). There was no strong evidence of a relationship between psychological stress or distress and clinical exacerbation. CONCLUSIONS: These data provide support for the notion that conflict and disruption in routine are related to subsequent disease activity in MS. However, this relationship is not sufficiently robust to predict clinical exacerbations reliably in individual patients.

Adult↗
PubMed2000

Intestinal inflammatory pseudotumour with regional lymph node involvement: identification of a new bacterium as the aetiological agent.

Inflammatory pseudotumours are the morphological expression of diverse processes such as reactive/reparative, infective, and neoplastic. This paper reports an example of intestinal inflammatory pseudotumour, with identification of a newly characterized bacterium in the lesion. The patient presented with intestinal obstruction. Laparotomy revealed a tumour in the terminal ileum causing stricture, and multiple enlarged regional lymph nodes. Histologically, the tumour and lymph nodes were composed of plump spindle cells disposed in a vague storiform pattern, and associated with lymphocytes and plasma cells. Immunohistochemical studies showed that most of the spindle cells were histiocytes (CD68 positive), prompting a search for a bacterial aetiology, akin to mycobacterial spindle cell pseudotumour. All histochemical stains for micro-organisms were unrewarding. Ultrastructural studies, however, revealed abundant bacteria within the spindle histiocytes. Polymerase chain reaction, using conserved oligonucleotide primers complementary to the 16S rRNA genes of eubacteria, was employed to amplify 16S rRNA gene fragments directly from the involved lymph node tissue. Phylogenetic analysis of the amplified DNA sequences revealed an organism with 99% sequence conformity to Pseudomonas veronii, a bacterium which has hitherto not been implicated in human infection. The importance of searching for an infective agent in inflammatory pseudotumour in the appropriate setting is re-emphasized.

Granuloma, Plasma Cell↗