FISHing for 1p19q codel in oligodendroglioma.

Together with isocitrate dehydrogenase (IDH) mutation, co-deletion of 1p19q (1p19q codel) is a prerequisite for diagnosis of oligodendroglioma, making it imperative that histopathology laboratories introduce testing for 1p19q codel. To date there is still no consensus reference range and cut-offs that confirm deletion of 1p or 19q. We embarked on determining our reference range in 11 formalinfixed, paraffin-embedded non-neoplastic brain tissue using fluorescence in situ hybridisation (FISH) with the Vysis 1p36/1q25 and 19q13/19p13 FISH Probe Kit (Abbott Molecular Inc., USA). At same time we attempted to validate our methodology in 13 histologically-confirmed IDH-mutant oligodendrogliomas. For 1p, percentage cells with deletion (range=8-23%; mean±SD = 15.73±5.50%) and target: control (1p36:1q25) ratio (range = 0.89-0.96; mean±SD = 0.92±0.03) in non-neoplastic brain, differed significantly (p<0.000) from oligodendroglioma (percentage cells with deletion: range = 49-100%; mean±SD = 82.46±15.21%; target:control ratio range:0.50-0.76; mean±SD = 0.59±0.08). For 19q, percentage cells with deletion (range = 7-20%; mean±SD = 12.00±3.49%) and target:control (19q13/19p13) ratio (range:0.90-0.97; mean±SD = 0.94±0.02) in non-neoplastic brain also differed significantly from oligodendroglioma (percentage cells with deletion: range = 45-100%; mean±SD = 82.62±18.13%; target:control ratio range:0.50-0.78; mean±SD = 0.59±0.09). Using recommended calculation method, for diagnosis of 1p deletion, percentage of cells showing deletion should be >32-33% and/or target:control ratio <0.83. For 19q, percentage of cells showing deletion should be >22% and target:control ratio <0.88. Using these cut-offs all 13 oligodendroglioma demonstrated 1p19q codel.

Screening for microsatellite instability in colorectal carcinoma: Practical utility of immunohistochemistry and PCR with fragment analysis in a diagnostic histopathology setting.

Since 2014, the National Comprehensive Cancer Network (NCCN) has recommended that colorectal carcinoma (CRC) be universally tested for high microsatellite instability (MSI-H) which is present in 15% of such cancers. Fidelity of resultant microsatellites during DNA replication is contingent upon an intact mismatch repair (MMR) system and lack of fidelity can result in tumourigenesis. Prior to commencing routine screening for MSI-H, we assessed two commonly used methods, immunohistochemical (IHC) determination of loss of MMR gene products viz MLH1, MSH2, MSH6 and PMS2 against PCR amplification and subsequent fragment analysis of microsatellite markers, BAT25, BAT26, D2S123, D5S346 and D17S250 (Bethesda markers) in 73 unselected primary CRC. 15.1% (11/73) were categorized as MSI-H while deficient MMR (dMMR) was detected in 16.4% (12/73). Of the dMMR, 66.7% (8/12) were classified MSI-H, while 33.3% (4/12) were microsatellite stable/low microsatellite instability (MSS/MSI-L). Of the proficient MMR (pMMR), 95.1% (58/61) were MSS/MSI-L and 4.9% (3/61) were MSI-H. The κ value of 0.639 (standard error =0.125; p = 0.000) indicated substantial agreement between detection of loss of DNA mismatch repair using immunohistochemistry and the detection of downstream microsatellite instability using PCR. After consideration of advantages and shortcomings of both methods, it is our opinion that the choice of preferred technique for MSI analysis would depend on the type of laboratory carrying out the testing.

Correlation of p16INK4a immunoexpression and human papillomavirus (HPV) detected by in-situ hybridization in cervical squamous neoplasia.

Persistence and eventual integration of high-risk HPV (hrHPV) into the cervical cell is crucial to the progression of cervical neoplasia and it would be beneficial to morphologically identify this transformation in routine surgical pathology practice. Increased p16(INK4a) (p16) expression is a downstream event following HPV E7 binding to pRB. A study was conducted to assess the correlation between hrHPV detection using a commercial in-situ hybridization assay (Ventana INFORM HPV ISH) and p16 immunoexpression (CINtec Histology Kit) in cervical squamous intraepithelial lesions and squamous carcinoma. 27 formalin-fixed, paraffin-embedded cervical low-grade squamous intraepithelial lesions (LSIL), 21 high-grade squamous intraepithelial lesions (HSIL) and 51 squamous carcinoma (SCC) were interrogated. hrHPV was significantly more frequent in HSIL (76.2%) and SCC (88.2%) compared to LSIL(37.0%). p16 expression was similarly more frequent in HSIL (95.2%) and SCC (90.2%) compared to LSIL(3.7%). That the rates of hrHPV when compared with p16 expression were almost equivalent in HSIL and SCC while p16 was expressed in only 1 of the 10 LSIL with hrHPV, are expected considering the likelihood that transformation has occurred in HSIL and SCC but does not occur in majority of LSIL.

Synovial sarcoma of the ethmoidal sinus.

BACKGROUND: Synovial sarcoma is a high-grade, soft tissue, malignant disease associated with poor outcome. Typically, synovial sarcoma involves the extremities, with less than 10 per cent of cases occurring in the head and neck region. Synovial sarcoma of the paranasal sinuses is a rare entity. This paper presents a case of an elderly patient with synovial sarcoma of the ethmoidal sinus. CASE REPORT: An 80-year-old woman who had right epistaxis underwent nasal endoscopy and biopsy. The pathology indicated synovial sarcoma and the patient underwent endoscopic excision of the tumour. CONCLUSION: Synovial sarcoma of the ethmoidal sinus is very rare. Patients should undergo excision of the tumour with post-operative radiotherapy. However, the prognosis remains poor and usually the patient succumbs to death within a year.

Cytokeratin immunoreactivity in Ewing sarcoma/ primitive neuroectodermal tumour.

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.

Histopathological landmarks of hepatocellular carcinoma in Malaysians.

A study was conducted at the Department of Pathology, University of Malaya Medical Centre, Kuala Lumpur into the histological type (WHO classification), grade (modified Edmondson and Steiner's grading system), mitotic rate, bile production, hyaline globule and Mallory hyaline formation of 52 cases of hepatocellular carcinoma (HCC) diagnosed during a 13-year period between 1st January 1990 to 31st December 2002. In addition, associated cirrhosis, dysplasia (large liver cell dysplasia: LLCD and small liver cell dysplasia: SLCD) and microvascular permeation were also looked for whenever the situation permitted. The patients' ages ranged from 21-years to 85-years (mean = 58.7 years) with a predilection for males and Chinese. Histologically, majority (73.1%) of the tumours demonstrated a trabecular pattern of growth. The bulk (73%) of the tumours were either of grade II or III differentiation. Mitotic activity ranged between 0-100/10 high power fields (hpf) with a mean of 22.2/10 hpf. Bile was noted in 25%, hyaline globules 17.3% and Mallory bodies in one case. Concomitant cirrhosis was present in 73.5%. 73.5% of the cases had associated LLCD. 5 with LLCD also showed SLCD. Microvascular permeation was shown in 76.2% of cases. On comparison with findings from other studies, no major difference seems to exist between the histological characteristics of our HCC cases and that of other populations.

Giant cell tumour of bone with late presentation: review of treatment and outcome.

PURPOSE: To review cases of giant cell tumour of bone or osteoclastoma managed at the University Malaya Medical Center, University of Malaya, Kuala Lumpur, from January 1990 to December 1999. METHODS: Medical records of all patients with musculoskeletal tumours were reviewed. Demographic data, clinical presentation, surgical management, and clinical outcomes were reviewed retrospectively. RESULTS: Most of the 31 patients who were treated for giant cell tumour of bone presented late on the basis of the duration of their symptoms and radiological features. Five of the patients had been referred for local recurrences. 26 patients were treated for primary tumours: 18 needed wide excision, 7 curettage, and one amputation. The joint could not be preserved and arthrodesis was performed for 11 patients. Three (12%) of the 26 patients had local recurrence during a mean follow-up of 60 months, including one (6%) who had recurrence after wide excision and 2 (29%) after curettage. Pulmonary metastasis was noted in 4 cases, 2 of which were confirmed histologically. CONCLUSION: Even in an advanced stage of disease, good clinical outcomes can be achieved with adequate excision and appropriate reconstruction. For lesions around the knee, autologous rotational grafting is a good alternative method of reconstruction.

Clonorchiasis/opisthorchiasis in Malaysians case reports and review.

Clonorchiasis and opisthorchiasis are snail-transmitted trematode infections. The disease is endemic in many parts of Asia. Local case reports have been predominantly in Chinese with a history of travel to endemic countries. Thus far, 20 cases of liver fluke infestation have been reported in this country. This report presents another two cases of clonorchiasis and a case of opisthorchiasis. We also briefly review pertinent aspects of the disease.

Malignant lymphoma of nasal septum--a case report.

Malignant lymphoma of nasal septum is uncommon. It presents a problem in diagnosis to both otorhinolaryngologist and pathologist. This case report is about one such patient in whom the local disease has been controlled with the treatment of radiotherapy alone. However it is suggested that combined treatment of radiotherapy and cytotoxic therapy might improve the survival rate.