Displaying publications 81 - 100 of 179 in total

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  1. Cheah PL, Looi LM, Sivanesaratnam V
    Pathology, 1993 Jul;25(3):250-2.
    PMID: 8265242
    We report the first documented Malaysian case of aggressive angiomyxoma (AAM) of the vulva. A 56-yr-old woman of Indian ethnic origin presented with a vulval lesion which was clinically mistaken for a Bartholin's cyst. The lesion was surgically excised and a diagnosis of AAM was made histologically. Of particular interest was the finding of foamy and mononuclear inflammatory cells and fibrin in the walls of most of the lesional blood vessels. The patient recovered uneventfully and remains without tumor recurrence at the time of writing 37 mths after initial presentation.
  2. Cheah PL, Looi LM, Horton S
    Am J Clin Pathol, 2017 12 20;149(1):1-7.
    PMID: 29267843 DOI: 10.1093/ajcp/aqx088
    Objective: To examine the cost of operating an anatomic pathology laboratory in a teaching hospital in Malaysia. Once the cost is determined, compare it with the costs of operating other laboratories in the same hospital, and operating anatomic pathology laboratories in other countries.

    Methods: Cost and workload data were obtained from hospital records for 2015. Time allocation of staff between laboratory testing and other activities was determined using assumptions from published workload studies.

    Results: The laboratory received 20,093 cases for testing in 2015, and total expenditures were US $1.20 million, ie, $61.97 per case. The anatomic pathology laboratory accounted for 5.2% of the laboratory budget at the hospital, compared to 64.3% for the clinical laboratory and 30.5% for the microbiology laboratory. We provide comparisons to a similar laboratory in the United States.

    Conclusions: Anatomic pathology is more costly than other hospital laboratories due to the labor-intensive work, but is essential, particularly for cancer diagnoses and treatment.

  3. Nizlan MN, Selvakumar K, Looi LM, Kunasegaran R
    Juxtafacet cyst of the spine is a rare occurrence. Reports have described them as synovial cysts; ganglion cysts; extradural cysts as well as degenerative cysts of the spine. Patients may present with radicular pain, motor deficits, sensory disturbances, cauda equina syndrome and even myelopathy. Lumbar juxtafacet cysts may be confused clinically with prolapsed intervertebral discs or other conditions involving nerve root compression such as arachnoid cysts, ependymal cysts, dermoid cysts or teratomatous cysts. In the case of the juxtafacet cyst, surgical excision is usually curative. We report a case of spinal synovial juxtafacet cyst found intraoperatively in a case that was preoperatively diagnosed as prolapsed intervertebral disc. Synovial juxtafacet cyst of the spine should be considered as one of the differential diagnoses in patients, especially in older patients, presenting with nerve root compression.
  4. Cheah PL, Chau YT, Looi LM
    Malays J Pathol, 2021 Dec;43(3):353-359.
    PMID: 34958056
    INTRODUCTION: Immunohistochemistry (IHC) was commenced in 1986 at the Department of Pathology, University of Malaya Medical Centre, Kuala Lumpur and its usage has grown for the past 30 over years, hence it was felt that a review was timely in view of the scarcity of literature on IHC usage.

    MATERIALS AND METHODS: All cases received by the Department of Pathology for histopathological examination between 1 July 2018 and 30 June 2019 were retrieved from the Laboratory Information System (LIS). All the IHC requests over this period were tabulated, with the exception of renal, muscle, rectal and nerve biopsies with their pre-defined algorithms for stains and cytological specimens. IHC stains performed solely for purpose of directing targeted treatment were also not included.

    RESULTS: Immunohistochemistry was performed in 2044 (21.1%) of the total of 9686 cases, with a total of 5969 IHC stains performed i.e. 2.9 (5969/2044) IHC stains per case. All 91 antibodies available were used at least once during the study. 14 histopathologists (5 with < 10-years and 9 with ≥ 10-years postgraduate specialist experience) reported on the cases with no significant difference (p=0.90) in their usage of IHC stains. Among the most common IHC stains used, requests for Ki67 and MNF116 showed higher standard deviations compared with p63, CK7 and S100 among the histopathologists. From the relatively higher standard deviation for Ki67 and MNF116 it appeared that there was a greater difference in the requesting pattern between histopathologists for these two antibodies.

    CONCLUSION: The rate of use of IHC in our centre seems compatible with that of an academic centre. Personal preferences of the histopathologists, rather than years of postgraduate specialist experience appeared to influence the rate of usage and choice of antibodies.

  5. Tham JH, Looi LM, Ghazali R
    Malays J Pathol, 2022 Dec;44(3):469-475.
    PMID: 36591714
    INTRODUCTION: Patients who are suspected of having prostate cancer from screening tests require a tissue biopsy to confirm the presence of cancer. This study aims to compare the cost and cancer detection rate of two different biopsy protocols: 6-core transrectal (TR) approach, and transperineal (TP) saturation biopsy.

    METHODS: In this descriptive, retrospective study, we selected all prostate biopsies received by the diagnostic pathology department of a tertiary hospital in Malaysia in the year 2020, from adult patients for analysis. Data on demographics, specimen preparation processes, and final histopathological diagnosis was extracted from the Laboratory Information System (LIS). The cost incurred for each biopsy diagnosed as cancer was calculated with the cost prices referenced from laboratory documentation. Statistical analysis was performed using SPSS, version 28.

    RESULTS: The total cost for detection of cancer using TR biopsy ranged from RM11.22 - RM271.02 with mean of RM47.53. The standard deviation, s is RM43.45. For TP biopsies, the total cost ranged from RM112.20 - RM349.56 with mean of RM160.85, standard deviation of RM80.37. TR biopsies had a detection rate of 43.2%, while TP biopsies had a 24.2% cancer detection rate. There is a 3.38-fold increase in costs between TR and TP biopsy.

    CONCLUSION: The results show a 3.38-fold increase in costs and a reduction in cancer detection rate when comparing TR and TP biopsy. The reason for the reduced detection rate is unascertained in this study.

  6. Tan EL, Looi LM, Sam CK
    Singapore Med J, 2006 Sep;47(9):803-7.
    PMID: 16924363
    Nasopharyngeal carcinoma (NPC) is an important cancer in Malaysia and is one of the major causes of cancer mortality in this country. This study evaluates the diagnostic and prognostic values in the quantitative relationship between the cell-free Epstein-Barr virus (EBV) deoxyribonucleic acid (DNA) load and the tumour burden.
  7. Misron NA, Looi LM, Nik Mustapha NR
    Asian Pac J Cancer Prev, 2015;16(4):1553-8.
    PMID: 25743830
    BACKGROUND: COX-2 has been shown to play an important role in the development of breast cancer and increased expression has been mooted as a poor prognostic factor. The purpose of this study was to investigate the relationship between COX-2 immunohistochemical expression and known predictive and prognostic factors in breast cancer in a routine diagnostic histopathology setting.

    MATERIALS AND METHODS: Formalin-fixed paraffin- embedded tumour tissue of 144 no special type (NST) invasive breast carcinomas histologically diagnosed between January 2009 and December 2012 in Hospital Sultanah Bahiyah, Alor Setar, Kedah were immunostained with COX-2 antibody. COX-2 overexpression was analysed against demographic data, hormone receptor status, HER2- neu overexpression, histological grade, tumour size and lymph node status.

    RESULTS: COX-2 was overexpressed in 108/144 (75%) tumours and was significantly more prevalent (87%) in hormone receptor-positive tumours. There was no correlation between COX-2 overexpression and HER2/neu status. Triple negative cancers had the lowest prevalence (46%) (p<0.05). A rising trend of COX-2 overexpression with increasing age was observed. There was a significant inverse relationship with tumour grade (p<0.05), prevalences being 94%, 83% and 66% in grades 1, 2 and 3 tumours, respectively. A higher prevalence of COX-2 overexpression in smaller size tumours was observed but this did not reach statistical significance. There was no relationship between COX-2 expression and lymph node status.

    CONCLUSIONS: This study did not support the generally held notion that COX-2 overexpression is linked to poor prognosis, rather supporting a role in tumorigenesis. Larger scale studies with outcome data and basic studies on cancer pathogenetic pathways will be required to cast further light on whether COX-2 inhibitors would have clinical utility in cancer prevention or blockage of cancer progression. In either setting, the pathological assessment for COX-2 overexpression in breast cancers would have an important role in the selection of cancer patients for personalized therapy with COX-2 inhibitors.

  8. Elbashier SH, Nazarina AR, Looi LM
    Malays J Pathol, 2013 Dec;35(2):139-45.
    PMID: 24362477
    Ewing sarcoma (ES)/ primitive neuroectodermal tumour (PNET) is an aggressive malignant neoplasm affecting mainly children and young adults. The tumour is included with other primitive neoplasms under the category of small round cell tumour. Cytokeratin expression in ES/PNET has been described in sporadic case reports as well as a few systemic series. We studied this feature in Malaysian patients diagnosed in University Malaya Medical Centre on the basis of typical morphology and immunohistochemical assays. Immunohistochemical staining for AE1/AE3 and MNF116 were performed in 43 cases. Cytokeratin was expressed in 17 cases (39.5%) in focal, intermediate or diffuse patterns. There was no significant association between cytokeratin immunoreactivity and the following parameters: patient age, sex, skeletal and extraskeletal primary location as well as primary, metastastic or recurrent tumours or chemotherapy treatment. A significant association between cytokeratin and neuron specific enolase (NSE) expression was demonstrated. Our study supports evidence of epithelial differentiation in ES/PNET and emphasizes that the expression of cytokeratin does not exclude ES/PNET in the differential diagnosis of small round cell tumours.
  9. Mun KS, Cheah PL, Baharudin NB, Looi LM
    Malays J Pathol, 2006 Dec;28(2):73-7.
    PMID: 18376794 MyJurnal
    Hepatocellular carcinoma (HCC) is among the ten most common cancers in Malaysian males. As cellular proliferation is an important feature of malignant transformation, we studied the proliferation pattern of normal and benign perineoplastic liver versus hepatocellular carcinoma in an attempt to further understand the tumour transformation process. 39 HCC (21 with accompanying and 18 without cirrhosis) histologically diagnosed at the Department of Pathology, University of Malaya Medical Centre between January 1992 and December 2003 were immunohistochemically studied using a monoclonal antibody to PCNA (Clone PC10: Dako). 20 livers from cases who had succumbed to traumatic injuries served as normal liver controls (NL). PCNA labeling index (PCNA-LI) was determined by counting the number of immunopositive cells in 1000 contiguous HCC, benign cirrhotic perineoplastic liver (BLC), benign perineoplastic non-cirrhotic (BLNC) and NL cells and conversion to a percentage. The PCNA-LI was also expressed as Ojanguren et al's grades. PCNA was expressed in 10% NL, 38.9% BLNC, 76.2% BLC and 71.8% HCC with BLNC, BLC and HCC showing significantly increased (p < 0.05) number of cases which expressed PCNA compared with NL. The number of BLC which expressed PCNA was also significantly increased compared with BLNC. PCNA-LI ranged from 0-2.0% (mean = 0.2%) in NL, 0-2.0% (mean = 0.3%) in BLNC, 0-3.6% (mean = 0.7%) in BLC and 0-53.8% (mean = 7.6%) in HCC with PCNA-LI significantly increased (p < 0.05) only in HCC compared with BLC, BLNC and NL. Accordingly, all NL, BLC and BLNC showed minimal (<5% cells being immunopositive) immunoreactivity on Ojanguren et al's grading system and only HCC demonstrated immunoreactivity which ranged up to grade 3 (75% of cells). From this study, there appears to be a generally increasing trend of proliferative activity from NL to BLNC to BLC and HCC. Nonetheless, BLNC and BLC, like NL, retained low PCNA-LI and only HCC had a significantly increased PCNA-LI compared with the benign categories. This is probably related to the malignant nature of HCC and may reflect the uncontrolled proliferation of the neoplastic hepatocytes.
  10. Cheah PL, Looi LM, Ghazalli R, Chua CT
    Malays J Pathol, 1999 Jun;21(1):59-62.
    PMID: 10879280
    A 31-year-old Malay female presented with nephrotic syndrome without renal impairment. Renal biopsy features were in keeping with immunotactoid glomerulopathy (ITG). Non-Congophilic deposits were seen causing thickening of the glomerular capillary basement membrane with segmental accentuation, and widening of the mesangium. Immunofluorescence examination showed moderate amounts of IgG and C3 in the glomerular capillary walls with some in the mesangium. Ultrastructurally, 20-nm thick fibrils with microtubular organisation were present predominantly in the subendothelial region with similar fibrils in the mesangium. Although immunotactoid glomerulopathy and fibrillary glomerulonephritis (FG) have been recognised as entities with extracellular fibrillary material in the kidney, to date much remains to be clarified regarding these 2 conditions. While the renal biopsy findings in this patient are consistent with ITG, her clinical presentation is unlike that of usual ITG in that she is of a much younger age and has no associated haemopoietic disorder. Response to initial treatment of 8 weeks of prednisolone therapy was poor.
  11. Cheah PL, Looi LM, Chua CT, Yap SF, Fleming S
    Malays J Pathol, 1997 Dec;19(2):115-20.
    PMID: 10879251
    Thirty-eight cases of lupus nephritis, all satisfying the American Rheumatism Association criteria for diagnosis of systemic lupus erythematosus (SLE), with renal involvement and biopsy were immunohistochemically studied for the expression of HLA-DR (DAKO: HLA-DR/alpha, TAL.1B5), one of the three known families belonging to the class II major histocompatibility complex (MHC), using a standard streptavidin-biotin-peroxidase method. 20 nephrectomies performed for renal trauma and tumours constituted the normal controls. Of the lupus nephritis cases, 34 were females and 4 males. Ethnically, 20 were Chinese, 13 Malay, 4 Indian and 1 of indigenous origin. Their ages ranged from 16 to 59 years (mean of 31 years). Histologically, 23 expressed World Health Organisation (WHO) class IV (diffuse proliferative), 10 WHO class V (diffuse membranous), 4 WHO class II (pure mesangiopathy) and 1 WHO class III (segmental and focal proliferative) nephritis. Activity scores ranged between 5 to 19 (mean = 8.6) and chronicity scored between 2 to 7 (mean = 3.2) on a standard scoring system. Similar to other studies, HLA-DR was expressed in the glomerular capillaries and peritubular capillaries of all and mesangium, tubules (proximal, distal and collecting), veins and arterioles of some normal controls. Interestingly, HLA-DR expression was noted in the arteries of 25% of the normal controls, a finding hitherto not reported. The frequency of lupus nephritis cases expressing HLA-DR in the various anatomical components did not differ significantly from the normal controls except that HLA-DR expression in arteries and arterioles was seen at a significantly increased frequency (p < 0.01) in lupus nephritis. This increased expression did not correlate with the WHO class, activity or chronicity scores. It therefore appears that MHC class II shows increased expression in the arterial system of lupus nephritis kidneys. The significance of this is unclear but could be related to heightened (gamma-interferon activation which may be a de novo phenomenon or result of T cell proliferation and activation in SLE.
  12. Ariffin H, Teh KH, Looi LM, Ariffin WA, Lin HP
    Med J Malaysia, 2001 Dec;56(4):497-9.
    PMID: 12014771
    Infantile myofibromatosis (IMF) is a rare tumour with a wide spectrum of disease activity ranging from a solitary cutaneous nodule through to a multicentric form with widespread visceral involvement. It is characterised by its unique ability to spontaneously regress and has a typical histological appearance of actin-positive fibroblasts arranged in whorls or fascicles and vessels in a pericytomatous pattern. A male infant with multiple lesions involving the subcutaneous tissue and bone from birth is described and followed-up for two years. Treatment of IMF is dependent on the location of the tumour/s with surgery or chemotherapy reserved for rapidly progressive or symptomatic disease. However, due to the low rate of recurrence and the possibility of spontaneous tumoral regression, therapeutic abstention, as practised in our patient, is justified.
  13. Ng KH, Ong SH, Bradley DA, Looi LM
    Appl Radiat Isot, 1997 Jan;48(1):105-9.
    PMID: 9022216
    Discriminant analysis of six trace element concentrations measured by instrumental neutron activation analysis (INAA) in 26 paired-samples of malignant and histologically normal human breast tissues shows the technique to be a potentially valuable clinical tool for making malignant-normal classification. Nonparametric discriminant analysis is performed for the data obtained. Linear and quadratic discriminant analyses are also carried out for comparison. For this data set a formal analysis shows that the elements which may be useful in distinguishing between malignant and normal tissues are Ca, Rb and Br, providing correct classification for 24 out of 26 normal samples and 22 out of 26 malignant samples.
  14. Ng KH, Tan KL, Gan SK, Looi LM
    Malays J Pathol, 1992 Jun;14(1):29-33.
    PMID: 1469915
    The use of the colloidal-gold technique in electron microscopy immunocytochemistry has provided important information on the in situ localisation of intracellular antigens. We have developed a post-embedding technique for prolactin localisation on resin-embedded human pituitary tissue sections by the use of the protein-A gold conjugate. Human pituitary tissue obtained at autopsy was processed for electron microscopical study without post-osmication and then embedded in Epon. The indirect immunoperoxidase method was used for light microscopical targetting of lactotroph cells for subsequent electron microscopical antigen localisation. Ultra-thin sections were labelled with human anti-human prolactin followed by protein-A gold conjugate. Specific labelling was observed over secretory granules with a density of 15-30 particles per granule, as determined by the Quantimet 570 image analysis system. This technique provides a means of studying the pathophysiology of hormonal secretion at ultrastructural level and can be a useful tool in diagnostic and research investigations.
  15. Cheah PL, Looi LM, Tan PE, Bosco J, Kuperan P
    Hematol Oncol, 1992 Nov-Dec;10(6):331-7.
    PMID: 1296933
    Cytophagic histiocytic panniculitis (CHP) is a recently recognized entity that frequently poses a perplexing diagnostic problem. Although the classical case presents with a relapsing fever, subcutaneous nodules, pancytopenia and liver dysfunction, most patients have in addition a multitude of other manifestations which confuse the clinical picture. Notwithstanding the variable clinical course, the disease frequently terminates in fatal hemorrhage. Diagnosis is based on histological features. A lobular panniculitis with an infiltrate of cytologically benign cytophagocytic histiocytes in skin nodules is the sine qua non of CHP. Hence, a deep skin biopsy which includes subcutaneous fat is mandatory to establish the diagnosis. Published information regarding this newly described entity remains scarce and we report two cases of CHP, one occurring in a 30-year-old Kadazan man and another in a 17-year-old Chinese woman seen at the University Hospital, Kuala Lumpur. The latter case presented with exudative ascites, an unusual feature, possibly due to intra-abdominal panniculitis. In addition, we record the development of cirrhosis in the same patient.
  16. Peh SC, Looi LM, Lam KL, Teh BH
    Malays J Pathol, 1987 Aug;9:73-8.
    PMID: 3452712
    In the 12-year period between 1974 and 1985, 19 children aged between 8 and 12 years with systemic lupus erythematosus (SLE) were seen in the Department of Paediatrics, University Hospital, Kuala Lumpur. A preponderance of females (M:F = 1:2.8) and ethnic Chinese was evident. Renal biopsies revealed a wide Iange of renal morphology, including minimal change glomerulonephritis, focal proliferative glomerulonephritis, diffuse proliferative glomerulonephritis with varying degrees of severity and membranous glomerulonephritis. The majority (15) of patients had clinical SLE at the time of renal biopsy, of whom 4 were also grossly nephrotic. In the remaining 4 patients a diagnosis of SLE was made after further investigation for nephrotic syndrome (2) and acute nephritis (2). The pattern of renal pathology in childhood lupus nephritis appears not to differ significantly from adults.
    Key words: Systemic lupus erythematosus, glomerulonephritis
  17. Cheah PL, Yap SF, Looi LM, Sivanesaratnam V
    Malays J Pathol, 1991 Jun;13(1):37-41.
    PMID: 1795560
    Squamous cell carcinoma-related antigen (SCC-Ag), first described by Kato and Torigoe in 1977, has been cited by various workers as a serological marker for some epithelial neoplasms. The most well-studied is its association with carcinoma of the uterine cervix. In January 1989, we embarked on a prospective, multivariate study at the University Hospital, Kuala Lumpur to assess the usefulness of serologically assaying SCC-Ag (using the Abbott RIA diagnostic kit) in our patients with carcinoma of the uterine cervix. We were also interested to ascertain whether SCC-Ag is a 'general' marker for all histological types of cervical carcinoma or specific for squamous carcinoma. From the time of commencement to June 1990, 35 newly-diagnosed and histologically-proven cases were entered into the study. Of these, 4 were keratinising squamous carcinoma, 18 large cell non-keratinising carcinoma, 3 adenosquamous carcinoma, 7 adenocarcinoma and 3 carcinoma-in-situ. Our preliminary results show that all keratinising squamous carcinoma and 1/3 each of large cell non-keratinising carcinoma, adenosquamous carcinoma and carcinoma-in-situ had positive pre-therapy serum SCC-Ag levels (i.e greater than 2 ng/ml, 2 ng/ml being an arbitrarily selected 'cut-off' value). In contrast, no adenocarcinoma was serologically positive. In addition, keratinising squamous carcinoma had the highest mean pre-therapy serum SCC-Ag level. The results imply that serum SCC-Ag is related to the (1) presence of squamous and not glandular differentiation and (2) degree of squamous differentiation.
  18. Yeoh NTL, Looi LM, Smiley TB
    Med J Malaysia, 1984 Jun;39(2):127-30.
    PMID: 6513850
    This paper discusses the feasibility of using a free pericardial patch in repairing defects of the esophagus. The experimental model used is the dog. A piece of the side wall of the esophagus is first excised. This defect in the esophagus is then covered
    with a free patch of pericardium. The animals are then sacrificed at sequential dates and the grafted site submitted for microscopic examination. The results show that a free graft of pericardium when used as a patch can prevent leakage of esophageal contents and allow healing of the defect without gross narrowing of the lumen.
  19. Cheah PL, Looi LM, Lin HP, Yap SF
    Cancer, 1990 Jan 1;65(1):174-6.
    PMID: 2152851
    In the 7-year period between 1980 and 1987, six cases of childhood primary hepatocellular carcinoma (PHC) were confirmed histologically in our institution. Hepatitis B surface antigen (HBsAg) seropositivity was confirmed in five of the cases, and tissue HBsAg was shown in four of these using the Shikata's orcein stain. An associated maternal HBsAg seropositivity was shown in two of the seropositive children. The youngest seropositive patient who developed PHC was 7 years old. The mother of this patient was also seropositive. These observations support a causal relation between childhood Hepatitis B virus infection and PHC. The importance of vertical or perinatal transmission of HBV in the causation of childhood PHC and the prophylactic role of childhood vaccination is emphasized. Attention is also drawn to the relative short malignant transformation time seen in some of these patients.
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