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Race-related morphologic variations in hepatocellular carcinoma

Sumithran E, Looi LM

Cancer, 1985 Sep 1;56(5):1124-7.
PMID: 2990666

In West Malaysia, hepatocellular carcinoma (HCC) is common in the Chinese and in the members of the Senoi aboriginal tribe, two racial groups with diametrically opposite life-styles. Certain fundamental differences exist between the liver tumors in the two races. In the Senoi, the tumor occurs in a younger age group and there is a greater male preponderance than in the Chinese. There is also a very close relationship between hepatitis B virus infection, chronic active hepatitis, cirrhosis, liver cell dysplasia, and HCC in the Senoi and the tumors generally present as multiple nodules studding both lobes of the liver. In the Chinese, although a relationship between hepatitis B virus infection, HCC, and cirrhosis exists, this association is not as strong as in the Senoi and the tumors are generally large and solitary. The data suggest that, although the hepatitis B virus is probably an important oncogenic agent in both racial groups, there may be a difference in the pathogenesis of HCC in the two races.
Quantitative assessment of breast density from digitized mammograms into Tabar's patterns

Jamal N, Ng KH, Looi LM, McLean D, Zulfiqar A, Tan SP, et al.

Phys Med Biol, 2006 Nov 21;51(22):5843-57.
PMID: 17068368

We describe a semi-automated technique for the quantitative assessment of breast density from digitized mammograms in comparison with patterns suggested by Tabar. It was developed using the MATLAB-based graphical user interface applications. It is based on an interactive thresholding method, after a short automated method that shows the fibroglandular tissue area, breast area and breast density each time new thresholds are placed on the image. The breast density is taken as a percentage of the fibroglandular tissue to the breast tissue areas. It was tested in four different ways, namely by examining: (i) correlation of the quantitative assessment results with subjective classification, (ii) classification performance using the quantitative assessment technique, (iii) interobserver agreement and (iv) intraobserver agreement. The results of the quantitative assessment correlated well (r2 = 0.92) with the subjective Tabar patterns classified by the radiologist (correctly classified 83% of digitized mammograms). The average kappa coefficient for the agreement between the readers was 0.63. This indicated moderate agreement between the three observers in classifying breast density using the quantitative assessment technique. The kappa coefficient of 0.75 for intraobserver agreement reflected good agreement between two sets of readings. The technique may be useful as a supplement to the radiologist's assessment in classifying mammograms into Tabar's pattern associated with breast cancer risk.
Fulltext Proliferating cell nuclear antigen (PCNA) activity in hepatocellular carcinoma, benign peri-neoplastic and normal liver

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.
Fulltext Progressive familial intrahepatic cholestasis in Malaysian patients--a report of five cases

Lee WS, Chai PF, Looi LM

Med J Malaysia, 2009 Sep;64(3):216-9.
PMID: 20527271

Progressive familial intrahepatic cholestasis (PFIC) is characterized by early onset cholestasis, progressive liver cirrhosis, pruritus, poor growth and inexorable progression to liver cirrhosis in early childhood. The serum level of gamma-glutamyl transferase is low or normal, which is discordant with severe cholestasis. Five Malaysian patients with PFIC, who all had typical features of PFIC with early onset of severe and progressive cholestasis, pruritus, cirrhosis and liver failure, were described. Three patients died as a result of the disease, while another one died due to post-liver transplant complication. The only survivor has compensated liver cirrhosis. Patients with severe cholestasis but has spuriously low yGT should be suspected of having PFIC. Liver transplant, which is life-saving in a majority of patients with PFIC, should be considered in all patients with PFIC.
Primary localised cutaneous amyloidosis in Malaysians

Looi LM

Australas J Dermatol, 1991;32(1):39-44.
PMID: 1930004

A review of consecutive biopsies from 85 Malaysian patients with primary localised cutaneous amyloidosis (PLCA) revealed 63 with papular amyloidosis (PA) and 22 with macular amyloidosis (MA). PLCA appeared to affect the Chinese more frequently than the other major ethnic groups but MA was more common than expected among the Indians. Of patients with PA, one had systemic lupus erythematosus, one scleroderma and in another, connective tissue disease was suspected. MA was not found to be associated with any other disease. Histologically, PA differed from MA by the larger size of amyloid deposits in the papillary dermis. There was no difference in their tinctorial and immunohistochemical characteristics. Deposits were permanganate-resistant and negative for AA protein, immunoglobulin light chains and keratin. A few cases exhibited positively for cytokeratin. Strong immunoreactivity for AP protein was observed. PA and MA appear chemically similar and are likely to be of epidermal origin.
Posttransplant lymphoproliferative disease masquerading as postbiopsy hematoma

Gan WH, Thye YL, Chang SH, Chua CB, Looi LM, Tan SY

Transplant Proc, 2004 Sep;36(7):2148-9.
PMID: 15518779
Phyllodes tumours of the breast: retrospective analysis of a University Hospital's experience

Toh YF, Cheah PL, Looi LM, Teoh KH, Tan PH

Malays J Pathol, 2016 Apr;38(1):19-24.
PMID: 27126660

Taking cognizance of the purported variation of phyllodes tumours in Asians compared with Western populations, this study looked at phyllodes tumours of the breast diagnosed at the Department of Pathology, University of Malaya Medical Centre over an 8-year period with regards to patient profiles, tumour parameters, treatment offered and outcome. Sixty-four new cases of phyllodes tumour were diagnosed during the period, however only 30 (21 benign, 4 borderline and 5 malignant) finally qualified for entry into the study. These were followed-up for 4-102 months (average = 41.7 months). Thirteen cases (8 benign, 3 borderline, 2 malignant) were Chinese, 9 (all benign) Malay, 7 (4 benign, 1 borderline, 2 malignant) Indian and 1 (malignant) Indonesian. Prevalence of benign versus combined borderline and malignant phyllodes showed a marginally significant difference (p=0.049) between the Malays and Chinese. Patients' ages ranged from 21-70 years with a mean of 44.9 years with no significant difference in age between benign, borderline or malignant phyllodes tumours. Except for benign phyllodes tumours (mean size = 5.8 cm) being significantly smaller at presentation compared with borderline (mean size = 12.5 cm) and malignant (mean size = 15.8 cm) (p<0.05) tumours, history of previous pregnancy, breast feeding, hormonal contraception and tumour laterality did not differ between the three categories. Family history of breast cancer was noted in 2 cases of benign phyllodes. Local excision was performed in 17 benign, 2 borderline and 3 malignant tumours and mastectomy in 4 benign, 2 borderline and 2 malignant tumours. Surgical clearance was not properly recorded in 10 benign phyllodes tumours. Six benign and all 4 borderline and 5 malignant tumours had clearances of <10 mm. Two benign tumours recurred locally at 15 and 49 months after local excision, however information regarding surgical clearance was not available in both cases. One patient with a malignant tumour developed a radiologically-diagnosed lung nodule 26 months after mastectomy, was given a course of radiotherapy and remained well 8-months following identification of the lung nodule.
P53 immunohistochemical expression: messages in cervical carcinogenesis

Cheah PL, Looi LM

Pathology, 2002 Aug;34(4):326-31.
PMID: 12190289

AIMS: The pattern of p53 expression was studied in pre-invasive and invasive cervical carcinoma in an attempt to clarify its role in cervical carcinogenesis.
METHODS: A total of 234 invasive cervical carcinomas (152 squamous cell carcinomas, 61 adenocarcinomas and 21 adenosquamous carcinomas) and 16 cervical intraepithelial neoplasia (CIN) I, six CIN II and 25 CIN III were immunohistochemically studied for p53.
RESULTS: p53 was detected more frequently in CIN and invasive carcinoma (100% of CIN I, 74.2% CIN II + III and 70.1% invasive carcinoma) compared with benign cervices (P< 0.001); however, only three squamous cell carcinomas, 11 adenocarcinomas and two adenosquamous carcinomas exhibited p53 expression in >75% of tumour nuclei. Six of the 11 adenocarcinomas and both adenosquamous carcinomas were poorly differentiated compared with one of the three squamous carcinomas. p53 immunoreactive cells were randomly distributed in invasive carcinoma, confined to the lower third of the epithelium in CIN I, reached the middle third in 20% of CIN II and upper third in 16.6% of CIN III.
CONCLUSIONS: Assuming that p53 immunoreactivity indicates gene mutation when the majority (> 75%) of neoplastic cells express p53, p53 mutations would seem uncommon in cervical carcinogenesis. Nonetheless, glandular malignancies, in particular poorly differentiated variants, may show a higher frequency of mutation. p53 was detected more frequently in CIN I compared with CIN II/III and invasive carcinoma which may be due to p53 protein degradation following interaction with high risk human papillomavirus E6 protein in CIN II/III and invasive carcinoma.
Outcome of biliary atresia in Malaysia: a single-centre study

Lee WS, Chai PF, Lim KS, Lim LH, Looi LM, Ramanujam TM

J Paediatr Child Health, 2009 May;45(5):279-85.
PMID: 19493120 DOI: 10.1111/j.1440-1754.2009.01490.x

This study aimed to determine the outcome of the operation of children with biliary atresia (BA) at a tertiary paediatric referral centre in Malaysia.
Morphological patterns of glomerular disease in renal biopsies from 1000 Malaysian patients

Prathap K, Looi LM

Ann Acad Med Singap, 1982 Jan;11(1):52-6.
PMID: 7073229

Adequately biopsied renal tissue received in the Department of Pathology, University Hospital, Kuala Lumpur from 1,000 consecutive Malaysian patients during an eleven year period between 1970 and 1981 was reviewed. The youngest patient was 6 days old and the oldest 80 years. Both sexes were equally represented. The majority of the patients were Chinese (71%) with Malays and Indians comprising most of the remainder. Over half the patients (50.4%) presented with the nephrotic syndrome. Other modes of presentation included systemic lupus erythematosus, proteinuria and haematuria separately or in combination and hypertension. Minimal change (25.7%) and proliferative glomerulonephritis (24.8%) were present in about equal numbers and together accounted for over half of the cases (50.5%). Lupus nephritis was the third most common diagnosis (18.4%). In addition, there were patients with focal glomerulonephritis (5.4%), membranous glomerulonephritis (5.5%), Berger's disease (5.8%), amyloidosis (0.6%) and end stage renal disease (4.0%).
Morphologic differences in the pattern of liver infiltration between systemic AL and AA amyloidosis

Looi LM, Sumithran E

Hum Pathol, 1988 Jun;19(6):732-5.
PMID: 2454214

Biopsy and necropsy tissue from 31 unselected patients with systemic amyloidosis, in which there was histologic evidence of liver involvement, were reviewed with reference to the location and pattern of amyloid deposition in the liver. Amyloidosis was classified into AA and AL types on the basis of immunohistochemistry and permanganate reaction of the amyloid deposits. Nineteen were categorized as AA (secondary) and 12 as AL (primary) amyloidosis. Deposition of AA amyloid was limited to the walls of vessels in the portal tract, constituting a "vascular" pattern. In AL amyloidosis, the deposits exhibited a "sinusoidal" pattern in that they were seen along hepatic sinusoids as well as in vessel walls. This difference was statistically significant (P less than .001). The histologic pattern of liver infiltration offers a valuable clue in the classification of systemic amyloidosis and provides information that may be useful in the selection of patients for therapy.
Minimal change glomerular disease in Malaysian adults and use of alternate day steroid therapy

Wang F, Looi LM, Chua CT

Q. J. Med., 1982;51(203):312-28.
PMID: 7146313

One hundred and forty-eight patients over the age of 12 years seen from July 1972 through December 1980 were accepted for this review of minimal change glomerular disease (MCGD). The diagnosis was based on a typical clinical presentation, and renal biopsy findings. MCGD forms 43.5 per cent of our patients with idiopathic nephrotic syndrome. The patients were predominantly young adults (82 per cent) and the onset of nephrotic syndrome (NS) occurred below the age of 30 years. Most patients had severe oedema and hypoalbuminaemia. Few patients recovered spontaneously. One hundred and thirty patients were given long-term alternate-day steroid (LASt) therapy. Four had cyclophosphamide alone, 21 patients had cyclophosphamide after a trial of LASt. Eighty-four patients (62.7 per cent) were initial responders: 17 of these after cyclophosphamide, 26 (19.4 per cent) were initial non-responders: five cyclophosphamide, 19 were late responders. Nine patients were partial responders, six were non-responders and one went into renal failure. Forty-one patients defaulted, emigrated or were seen only locally at the time of study. Ninety-nine patients were followed for three to 102 months (mean 23 . 3 months). Thirty-seven patients were followed for 36 to 102 months. Relapses were infrequent but occurred as late as 60 months.
Microwave-stimulated formaldehyde fixation of experimental renal biopsy tissues: computerised morphometric analysis of distortion artefacts

Looi LM, Loh KC

Malays J Pathol, 2005 Jun;27(1):23-7.
PMID: 16676689

Although microwave irradiation has been used in the histopathology laboratory for several years, there has been minimal published experimental data on its effects on the technical and staining quality of histological sections. Furthermore, it has not been clear whether the advantages gained in reduction of fixation and staining duration has been at the expense of increasing architectural distortion to the tissues. We report here our experience with computerised morphometric analysis to investigate glomerular artifacts caused by microwave-stimulated fixation of renal tissues. 39 rat and 33 human autopsy kidney samples were subjected to (1) fixation in neutral buffered formaldehyde (control), (2) microwave-stimulated fixation followed by neutral buffered formaldehyde, and (3) neutral buffered formaldehyde followed by microwave irradiation. In addition, the effect of post-fixation in 70% ethanol was also investigated. Microwave irradiation was delivered through a dedicated laboratory microwave oven at 80% power and at 55 degrees C for 3 minutes. The different fixation methods were compared with regards to shrinkage (distortion) to glomerular structures (glomeruli and Bowman's spaces) on H and E sections, as determined by morphometric image analysis using a temporary assembled-system consisting of a trinocular microscope, a digital video camera and personal computer. A FlashPoint VGA 3.3 film-grabber card was used to capture images for morphometric analysis by using a Scion Image program. Morphometric analysis of glomerular structures showed that microwaves caused more shrinkage to the area bounded by the Bowman's capsule than the glomerulus proper, but post-fixation with ethanol reduced this shrinkage. These findings have implications on the logistics of tissue preparation of renal biopsies in clinical practice.
Microscopical atrial amyloidosis in chronic heart disease

Looi LM

Histopathology, 1981 Nov;5(6):615-22.
PMID: 7319480

Nineteen out of 121 consecutive cardiac biopsies from 107 patients were found to contain amyloid deposits on routine Congo red screening. Seventeen were left atrial appendages removed during mitral valvotomy for chronic rheumatic mitral valve disease while the remaining two were right atrial appendages excised during surgical repair of atrial septal defects. The distribution of amyloid deposits within the atria and their tinctorial characteristics are described. The high prevalence of atrial amyloidosis observed could not be attributed to generalized or senile amyloidosis. The possibility that this is a distinctive localized form of amyloidosis secondary to chronic heart disease is discussed.
Microcalcification clustering parameters in breast disease: a morphometric analysis of radiographs of excision specimens

Ng KH, Looi LM, Bradley DA

Br J Radiol, 1996 Apr;69(820):326-34.
PMID: 8665132

X-ray microradiography of surgically excised breast specimens offers the possibility of morphological characterization of calcifications. When combined with digital imaging techniques there exists added potential for obtaining valuable basic quantitative morphometric information regarding differences between microcalcifications in tissues exhibiting evidence of fibrocystic change, benign and malignant tumours. A total of 157 excised breast specimens from 84 patients were microradiographed using a Softex Super Soft X-ray unit and Kodak AA high resolution industrial film. A Quantimet 570C image analysis system was used to digitize and analyse the microradiographs. Of the 157 microradiographs, 51 (from 30 patients) revealed microcalcification clusters. The existence of significant differences between the three identified categories of tissue were indicated by clustering parameters. These included the number of particles per cluster, area of clusters, maximum distance to nearest neighbour, and geometric mean distance to nearest neighbour. The distribution pattern index (DPI), another of the clustering parameters used in this study, has been observed to be a particularly powerful discriminator. The value for fibrocystic change was found to be significantly smaller (0.514) than that for benign tumour (0.796) whilst that for benign tumour was observed to be significantly larger than that for malignant tumour (0.604) at a p-value of less than 0.05 (Kruskal-Wallis one-way analysis of variance).
Fulltext Metastatic Adenocarcinoma Presenting as Extensive Cavoatrial Tumor Thrombus

Johari B, Abdul Aziz YF, Krishnasamy S, Looi LM, Hashim SA, Raja Mokhtar RA

Iran J Radiol, 2015 Apr;12(2):e11197.
PMID: 26060549 DOI: 10.5812/iranjradiol.11197

The presence of tumor thrombus in the right atrium is frequently the result of direct intraluminal extension of infra-diaphragmatic malignancy into the inferior vena cava (IVC) or supradiaphragmatic carcinoma into the superior vena cava (SVC). Right atrial tumor thrombus with extension into both SVC and IVC has not been reported in the literature. We present a patient who presented with symptoms of right atrial and SVC obstruction. Imaging revealed presence of a thrombus in the right atrium, extending to the SVC and IVC, with the additional findings of a left adrenal mass and multiple liver lesions. The histopathological examination of the right atrial mass revealed metastatic adenocarcinoma cells. The patient was given a presumptive diagnosis of metastatic adenocarcinoma, most likely adrenal in origin, with multiple hepatic lesions suspicious for metastasis. The clinical outcome of the patient was not favorable; the patient succumbed before the adrenal mass could be confirmed to be the primary tumor. This case highlights that in patients manifesting with extensive cavoatrial thrombus as, the existence of primary carcinoma should be considered especially in the adrenal cortex or in the lung.
Mesangial IGM in minimal change glomerular disease: a clinicopathological study in a Malaysian population

Looi LM, Wang F, Lam KL, Chua CT

Pathology, 1985 Jan;17(1):41-4.
PMID: 3889788

During a 6 yr period, 105 (69%) of 153 patients in whom a histological diagnosis of minimal change glomerular disease was made had renal biopsy tissue suitable for immunofluorescence examination. Thirty seven (35%) patients showed glomerular mesangial deposits of IgM. All the patients presented with the nephrotic syndrome. We found no significant difference in age and sex prevalence, presentation, response to therapy and glomerular morphology between IgM positive and IgM negative groups. This study suggests that there is no necessity to categorize IgM positive minimal change glomerular disease as a separate entity.
Medico-legal aspects of histopathology practice

Ong BB, Looi LM

Malays J Pathol, 2001 Jun;23(1):1-7.
PMID: 16329541

Medico-legal problems experienced by histopathologists differ from those of other clinicians as they are rarely in direct contact with patients. Nevertheless, the pathologist owes a duty of care to the patient and is liable for medical negligence. In the absence of local guidelines, it is prudent to follow guidelines published by learned Colleges elsewhere. This is also true when delegating duties to non-pathologists, technical and other support staff. Errors in diagnosis and documentation pose the most common problems in histopathology. In this, liability also depends on many factors including the provision of adequate clinical information by clinicians and competence of laboratory staff. Clinicopathological discussions, participation in quality assurance programmes and adherence to standard operating procedures are important audit activities to minimize and detect errors as well as prevent grievous outcome to patients. Issues also arise over the retention of specimens and reports. In general, wet, formalin-fixed tissues should be kept until histopathological assessment is finalized and preferably after clinicopathological sessions, and even longer if there is potential litigation. Reports should be archival. Paraffin blocks should be kept for at least the lifetime of the patient, and histology slides for at least 10 years, to facilitate review and reassessment. Despite adverse publicity in the foreign press over the use of human organs and tissues for research and education, it is accepted that processed tissues can be used for research and educational purposes provided the patient's identity is kept confidential. Nevertheless, it would be prudent to revise consent forms for surgery and autopsies to include the possibility that tissues removed can be stored or used for research and education. Good medical practice in pathology encourages a willingness to consult colleagues when in doubt, but advises that the treating clinician be informed if histopathological material is referred away for a second opinion. The Telemedicine Act of Malaysia (1997) requires practitioners outside Malaysia providing diagnosis through telepathology to hold a certificate to practice telemedicine issued by the Malaysian Medical Council. It is likely that the medico-legal scene in histopathology will change in the coming years with the advent of other new ancillary investigative techniques.
Medicine in Malaysia: pathology

Looi LM

Med J Malaysia, 1995 May;50 Suppl A:S51-5.
PMID: 10968016
Mammographic breast glandularity in Malaysian women: data derived from radiography

Jamal N, Ng KH, McLean D, Looi LM, Moosa F

AJR Am J Roentgenol, 2004 Mar;182(3):713-7.
PMID: 14975974

This study was undertaken to estimate mammographic breast glandularity in Malaysian women from radiographic data.

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