Flexi-Myo Panel Strategy: Genomic Diagnoses of Myopathies and Muscular Dystrophies by Next-Generation Sequencing.

Aims: Muscle disorders are clinically and genetically heterogeneous. Investigations, including plasma creatine kinase, electromyography, and nerve conduction velocity studies are often nonspecific, whereas muscle biopsy might be limited by sampling bias and variable histopathology. Next-generation sequencing is now generally considered an important diagnostic tool for muscle disorders, with decreased costs and improved diagnostic yield. Inclusion of a large number of genes in the analysis might, however, generate a large number of ambiguous results and create unnecessary confusion for clinicians and patients. Methods: An ethnic Chinese patient presented at age 10 with tip-toe walking. Upon examination the patient had a waddling gait, a tight Achilles tendon with pes cavus. A muscle biopsy showed the presence of minicores with disruption of the myofibrillary network and Z-bands. Sequencing was performed using the Flexi-Myo panel, which provides coverage for 85 myopathic genes. Reporting of sequencing results was decided by the responsible chemical pathologists based on the available clinical and genetic information. Results: A previously identified heterozygous in-frame deletion was detected in MYH7, which confirmed the diagnosis of Laing myopathy. No variants of uncertain significance required reporting. Conclusion: We describe the effectiveness of our Flexi-Myo panel approach for the diagnosis of muscle disorders, which confirmed diagnosis of Laing myopathy in what had been a clinically ambiguous presentation. This approach enables efficient genomic testing for muscle diseases in adults and children with satisfactory diagnostic yield and sufficient sensitivity, whereas avoiding the reporting of ambiguous results. Similar strategies might also be implemented for other groups of disorders.

A fetus coexisting with a complete hydatidiform mole with trisomy 9 of maternal origin.

A complete hydatidiform mole (CHM) coexisting with a viable fetus is a rare finding in pregnancies. Accurate diagnosis often relies on ultrasonographic, histopathological and molecular techniques in the definite diagnosis. To the best of our knowledge, a liveborn fetus coexisting with CHM with trisomy 9 has not been described. The use of molecular genotyping and immunohistochemical laboratory investigations enabled the CHM to be fully characterized. Postzygotic diploidization of a triploid conception arising from dispermy is the proposed mechanism of its formation.

Prospective study on dialysis patients after total parathyroidectomy without autoimplant.

AIM: Secondary hyperparathyroidism is common in chronic kidney disease. When medical treatment fails, subtotal or total parathyroidectomy with autoimplant is done but both are associated with a high recurrence rate. The third surgical strategy is total parathyroidectomy without autoimplant. We evaluate the outcomes of patients who had total parathyroidectomy with no autoimplant. METHODS: Thirteen patients who had total parathyroidectomy without autoimplant were prospectively studied from 1998-2002. Intact parathyroid hormone, biochemistry and bone mineral densities were measured at baseline and serially. All patients had bone biopsies done preoperatively and seven had repeat bone biopsies at a mean of 37.7 months postoperatively. Histomorphometric studies were done for all bone biopsies. Patients were observed for fractures. RESULTS: Five patients were on haemodialysis and eight on peritoneal dialysis. Mean duration of follow up was 68 months. Postoperatively, mean intact parathyroid hormone decreased precipitously and remained within or just above normal. Mean serum calcium phosphate product decreased and remained normal. Out of seven patients who had repeat bone biopsies, two showed reversal of hyperparathyroid bone disease to normal, two had mild hyperparathyroidism, while three had adynamic bone disease. One patient with adynamic bone disease subsequently developed biochemical recurrence of hyperparathyroidism. Serial bone densitometry showed remarkable improvement. There was no fracture. CONCLUSION: In the studied series of total parathyroidectomy without autoimplant, adynamic bone disease occurred in three out of seven repeat bone biopsies while improvement occurred in the rest. Bone mineral density was much improved and there was no fracture.

Inter- and intra-observer concordance of cyberpathology in twenty-five cases.

To study the feasibility of anatomical pathology consultation in cyberspace (cyberpathology) and to determine inter- and intra-observer concordance. Twenty-five consecutive cytology and histopathology cases are photographed using a digital camera placed against the eyepiece, and uploaded to an image-server in the Internet. Participants view the images, rate their confidence, and provide a diagnosis. They then view the original glass slides and provide a final diagnosis. The diagnoses are compared for inter- and intra-observer concordance. Participants are confident of their diagnoses based on viewing images on the Internet. The intra-observer concordance exceeds 95% individually, and 96% overall. Inter-observer concordance was 100% in a subset of cases. Cyberpathology as described is both available and affordable and is a valid alternative to slide-based anatomic pathology consultation.

Identification of HPV-16 in Borderline Mucinous Cystic Neoplasm of Pancreas.

Pancreatic mucinous cystic neoplasms (PMCN) predominantly affect women in the reproductive age, are located in the body and tail of the pancreas, and share morphological features with similar tumors of the ovary. We report the detection of human papillomavirus (HPV) using several different PCR protocols in a borderline PMCN from a female patient. Type-specific PCR demonstrated the HPV to be type 16. If confirmed by others, this group of neoplasms might become preventable by HPV vaccination.

A novel mutation (C271F) in the Notch3 gene in a Chinese man with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy.

BACKGROUND: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an adult-onset hereditary condition caused by mutations in the Notch3 gene. A Chinese man was studied. METHOD: Electronic microscopy examination of skin biopsy. The Notch3 gene was screened for mutations by polymerase chain reaction and direct DNA sequencing. RESULTS: Electronic microscopy showed the presence of deposits of granular osmiophilic material in dermal capillaries in the index patient. A novel heterozygous C271F in exon 6 was detected in the index patient. This heterozygous C271F mutation was also detected in the asymptomatic elder son but was not detected in the asymptomatic wife of the patient. Allele specific amplification showed that C271F was not detected in 100 normal subjects. CONCLUSION: We established the molecular basis of CADASIL in a Chinese man. Mutation detection assay provides a reliable method for confirming the diagnosis of CADASIL.

The comparative pathology of severe acute respiratory syndrome and avian influenza A subtype H5N1--a review.

The pathology of 2 zoonotic human viral infections that recently emerged, severe acute respiratory syndrome (SARS) due to coronavirus (SARS-CoV) and avian influenza A subtype H5N1, is reviewed and compared based on the literature and the cases examined by the authors. Pneumocytes are the primary target of infection resulting in diffuse alveolar damage. Systemic cytokine activation results in hemophagocytic syndrome, lymphoid depletion, and skeletal muscle fiber necrosis. Severe acute respiratory syndrome induces a more fibrocellular intra-alveolar organization with a "bronchiolitis obliterans organizing pneumonia"-like pattern and presence of multinucleated histiocytes and pneumocytes. H5N1 causes a more fulminant and necrotizing diffuse alveolar damage with patchy and interstitial paucicellular fibrosis. Severe acute respiratory syndrome associated coronavirus persists in the lung up to the second month, whereas H5N1 persists in the lung up to the third week. Severe acute respiratory syndrome associated coronavirus disseminates to blood, urine, feces, gastrointestinal tract, and liver. There is recent report of possible cerebral involvement by H5N1 and its isolation in the blood, gastrointestinal tract, and cerebrospinal fluid. More pathologic studies are urgently needed.

Cervical Cancer Screening for the Reluctant - HPV Testing of Air-Dried Vaginal Discharge.

Despite the availability of the PAP test, cervical cancer continues to cause considerable morbidity and mortality. Many women default cervical cytology for a variety of reasons. This demands the development of alternative screening strategies, such as HPV testing on self-procured cervical-vaginal specimens in order to capture this group of women. We investigated the self-procured air-dried vaginal discharge for HPV testing. We recruited 82 patients with HPV-associated cervical lesions and 36 patients with normal cervical pathology. Participants were briefed and informed consents obtained. Each was then given a kit containing written instructions, a slim napkin, an empty zip-lock plastic bag for soiled napkin specimen, and a return envelope. After wearing the napkin for the day, the patient removes it, dries it, and returns the specimen by mail. Specimens were batched and a 0.5 cm area of each stained napkin was tested for HPV by PCR. Specimens from all 26 patients with high-grade (CIN 2 or above) HPV-induced cervical lesions and 4 of 36 normal subjects tested positive for HPV, giving a sensitivity and specificity of 100% and 88.9%, respectively. We propose offering to women who refuse cervical cytology the alternative screening strategy of testing of self-procured air-dried vaginal discharge for HPV. This method of cervical cancer screening is also suitable for people living in remote regions of the world.

Coronaviral hypothetical and structural proteins were found in the intestinal surface enterocytes and pneumocytes of severe acute respiratory syndrome (SARS).

Severe acute respiratory syndrome (SARS) is a newly emerging infectious disease that haunted the world from November 2002 to July 2003. Little is known about the biology and pathophysiology of the novel coronavirus that causes SARS. The tissue and cellular distributions of coronaviral hypothetical and structural proteins in SARS were investigated. Antibodies against the hypothetical (SARS 3a, 3b, 6, 7a and 9b) and structural proteins (envelope, membrane, nucleocapsid and spike) of the coronavirus were generated from predicted antigenic epitopes of each protein. The presence of these proteins were first verified in coronavirus-infected Vero E6 tissue culture model. Immunohistochemical studies on different human tissues, including a cohort of nine autopsies, two liver biopsies and intestinal biopsies of SARS patients, further confirmed the existence of coronaviral hypothetical and structural proteins in the cytoplasm of pneumocytes and small intestinal surface enterocytes in SARS patients. With this vast array of antibodies, no signal was observed in other cell types including those organs in which reverse transcriptase-polymerase chain reactions were reported to be positive. Structural proteins and the functionally undefined hypothetical proteins were expressed in coronavirus-infected cells with distinct expression pattern in different organs in SARS patients. These antipeptide antibodies can be useful for the diagnosis of SARS at the tissue level.

MSH2 c.1452-1455delAATG is a founder mutation and an important cause of hereditary nonpolyposis colorectal cancer in the southern Chinese population.

Hereditary nonpolyposis colorectal cancer (HNPCC) accounts for approximately 2% of all colorectal cancer (CRC) cases and is the most common hereditary CRC syndrome. We have previously reported a high incidence of microsatellite instability (MSI) and germline mismatch repair (MMR) gene mutations in young Hong Kong Chinese with CRC. Ongoing studies at the Hereditary Gastrointestinal Cancer Registry in Hong Kong have revealed a unique germline MSH2 c.1452-1455delAATG mutation that has not been reported in other ethnic groups. Detailed analysis showed that this specific MSH2 mutation constituted 21% of all germline MMR gene mutations and 36% of all MSH2 germline mutations identified. We designed a specific PCR-based diagnostic test on paraffin-embedded tissues and identified this germline mutation in 2 (1.5%) of 138 consecutive patients with early-onset CRC (<46 years of age at diagnosis). Haplotype analysis was performed using 11 microsatellite markers located between D2S391 and D2S123. All 10 families had the same disease haplotype, suggesting a founder effect. These 10 families all originated from the Chinese province of Guangdong, which historically included Hong Kong. It is the most populous of the Chinese provinces, with a population of >93 million. Further analysis suggested that this founder mutation may date back to between 22 and 103 generations ago. The identification of this MSH2 founder mutation has important implications for the design of mutation-detection strategies for the southern Chinese population. Since there were major emigrations from Hong Kong and Guangdong province during the 19th and 20th centuries, this finding is also significant for Chinese communities worldwide.

SARS-associated viral hepatitis caused by a novel coronavirus: report of three cases.

Liver impairment is commonly reported in up to 60% of patients who suffer from severe acute respiratory syndrome (SARS). Here we report the clinical course and liver pathology in three SARS patients with liver impairment. Three patients who fulfilled the World Health Organization case definition of probable SARS and developed marked elevation of alanine aminotransferase were included. Percutaneous liver biopsies were performed. Liver specimens were examined by light and electron microscopy, and immunohistochemistry. Reverse-transcriptase polymerase chain reaction (RT-PCR) using enhanced real-time PCR was applied to look for evidence of SARS-associated coronavirus infection. Marked accumulation of cells in mitosis was observed in two patients and apoptosis was observed in all three patients. Other common pathologic features included ballooning of hepatocytes and mild to moderate lobular lymphocytic infiltration. No eosinophilic infiltration, granuloma, cholestasis, fibrosis, or fibrin deposition was noted. Immunohistochemical studies revealed 0.5% to 11.4% of nuclei were positive for proliferative antigen Ki-67. RT-PCR showed evidence of SARS-associated coronavirus in the liver tissues, but not in the sera of all 3 patients. However, electron microscopy could not identify viral particles. No giant mitochondria, micro- or macro-vesicular steatosis was observed. In conclusion, hepatic impairment in patients with SARS is due to SARS-associated coronavirus infection of the liver. The prominence of mitotic activity of hepatocytes is unique and may be due to a hyperproliferative state with or without disruption of cell cycle by the coronavirus. With better knowledge of pathogenesis, specific therapy may be targeted to reduce viral replication and modify the disease course.

Outcomes and prognostic factors in 267 patients with severe acute respiratory syndrome in Hong Kong.

BACKGROUND: Severe acute respiratory syndrome (SARS) has become a global public health emergency. OBJECTIVE: To evaluate the characteristics and outcomes of patients with SARS in Hong Kong and to identify predictors of mortality. DESIGN: Retrospective cohort study. SETTING: Quarantine hospital for patients with SARS in Hong Kong. PATIENTS: 267 consecutive patients hospitalized from 26 February to 31 March 2003 for probable or confirmed SARS. MEASUREMENTS: Clinical, laboratory, and radiographic measures; 3-month mortality rate. RESULTS: According to our case definition, there were 227 cases of confirmed SARS and 40 cases of probable SARS. Common presenting symptoms were fever (99% of patients), chills (74%), malaise (63%), and myalgia (50%). Laboratory findings included lymphopenia (73%), thrombocytopenia (50%), hyponatremia (60%), and elevated levels of lactate dehydrogenase (47%) and C-reactive protein (75%). During hospitalization, incidence of diarrhea (53%), anemia (53%), and acute renal failure (6%) increased. Sixty-nine patients (26%) required intensive care because of respiratory failure. The 3-month mortality rate was 12% (95% CI, 8% to 16%). Factors contributing to mortality were respiratory failure, acute renal failure, and nosocomial sepsis. On multivariate Cox regression, age older than 60 years (relative risk, 5.10 [CI, 2.30 to 11.31]; P < 0.001) and lactate dehydrogenase level greater than 3.8 micro kat/L at presentation (relative risk, 2.20 [CI, 1.03 to 4.71]; P = 0.04) were independent predictors of mortality. CONCLUSION: Because of the longer follow-up period in our cohort, the mortality rate in these patients is higher than rates reported in previous studies. Advanced age and high lactate dehydrogenase level at presentation predict mortality. *For members of the Princess Margaret Hospital SARS Study Group, see the Appendix.

T-cell/histiocyte-rich diffuse large B-cell lymphoma. Report of a case diagnosed by fine needle aspiration biopsy with immunohistochemical and molecular pathologic correlation.

BACKGROUND: T-cell-rich B-cell lymphoma (TCRBL) is a lymphoma of B-cell type associated with a prominent component of T cells (constituting > 50% of the cellular population). We report the first case of TCRBL diagnosed by fine needle aspiration (FNA). It was confirmed by subsequent lymph node excision biopsy. CASE: A 37-year-old woman presented with a short history of chest wall pain. Examination revealed induration, warmth and armorlike swelling of the right anterior chest wall, axilla and upper arm, with matted lymph nodes in the ipsilateral axilla and supraclavicular fossa. FNA showed a polymorphic, lymphoid aspirate, among which were many small lymphocytes, significant numbers of centroblastlike cells and a few markedly atypical lymphoid cells with convoluted nuclei. Histiocytes, freely lying karyorrhectic debris and mitotic figures were readily identified. Plasma cells, eosinophils and Reed-Sternberg cells were not seen. The cell block contained similar cells, with larger lymphoid cells scattered among smaller lymphocytes. Immunohistochemical studies showed that the larger cells were B cells. Molecular studies on the cell block confirmed an immunoglobulin gene rearrangement. CONCLUSION: TCRBL is a distinct type of lymphoma that can be accurately diagnosed by FNA.

Novel mutations in the PATCHED gene in basal cell nevus syndrome.

Basal cell nevus syndrome (BCNS) is an autosomal dominant disease characterized by the presence of multiple basal cell carcinomas, odontogenic keratocysts, palmoplantar pits, and calcification in the falx cerebri caused by mutational inactivation of the PTCH gene. To investigate the molecular basis of BCNS in Chinese, we did a mutational analysis of the PTCH gene by performing denaturing high-performance liquid chromatography in three BCNS families. In this study, three novel mutations, two 1-bp frameshift insertions, i.e., 1468insA and 2392insC, and one 8-bp deletion, i.e., IVS5 + 1delGTAAGTGT, affecting a donor splice site, were identified. All the mutations cause a shift of the open reading frames and lead to premature termination of PTCH protein translation. Our results showed that mutational inactivation of the PTCH gene causes BCNS in Chinese.

A malignant gastrointestinal stromal tumor with osteoclast-like giant cells.

Gastrointestinal stromal tumors (GISTs) are a heterogeneous group of mesenchymal tumors with a wide spectrum of histologic features and consistent expression of c-Kit. We describe an 85-year-old woman who presented with left lower quadrant abdominal pain and was subsequently diagnosed as having a malignant GIST. The tumor was composed of short fascicles of spindle cells. In addition to the presence of tumor giant cells, the tumor also demonstrated many osteoclast-like giant cells, a feature that has not been previously described in the literature. These giant cells expressed histiocytic markers CD68 and alpha(1)-antitrypsin but not c-Kit, a marker for GISTs. Electron microscopy showed no features of smooth muscle differentiation in the giant cells. The possible origin of the osteoclast-like giant cells is discussed in the context of immunohistochemical and ultrastructural characteristics.

Clear-cell sarcoma diagnosis by fine-needle aspiration: cytologic, histologic, and ultrastructural features; potential pitfalls; and literature review.

A definitive diagnosis of clear-cell sarcoma of soft parts (CCSSP) is possible by fine-needle aspiration (FNA) biopsy alone. The aspirates are markedly cellular, consisting predominantly of discohesive cells but also of cohesive cells. The cytoplasm is eosinophilic and eccentric. The nuclei are round and contain macronucleoli. CCSSP should be considered when FNA of a soft-tissue tumor shows uncharacteristically high cellularity and relatively uniform cells with macronucleoli. Cohesion of some tumor cells does not rule out CCSSP. Melanin pigment and cytoplasmic clearing are infrequent and not necessary for the diagnosis. Sufficient material should always be procured for immunohistochemical studies on the cell block. Seven other cases are found in the literature, all correctly diagnosed by FNA. Although it is rare, CCSSP is a highly malignant tumor that can be diagnosed readily by FNA without resorting to incisional biopsy.

Transjugular liver biopsy with an automated trucut-type needle: comparative study with percutaneous liver biopsy.

OBJECTIVE: Transjugular liver biopsy using the suction method usually produces small specimens with excessive fragmentation, hence the diagnosis adequacy of specimens and the clinical impact of performing the biopsy have been questioned. An alternative biopsy needle, the Quick-Core needle system, which uses an automated trucut-type mechanism, has been shown to produce non-fragmented tissue specimens. The aim of the present study was to evaluate the safety, adequacy and clinical impact of the transjugular liver biopsy by comparing it with the standard percutaneous liver biopsy. DESIGN: We recruited all patients who underwent liver biopsies by percutaneous or transjugular routes in the Department of Medicine, Princess Margaret Hospital, Hong Kong between January 1998 and December 1999. METHOD: We recorded demographics and clinical features of patients, indications and complications, and the clinical impact of the liver biopsy procedure. All liver biopsy specimens were reviewed by the histopathologist, who was blinded to the approach of taking the biopsy. All variables between patients undergoing transjugular and percutaneous liver biopsies were compared. RESULTS: During the study period, 50 percutaneous and 18 transjugular liver biopsies were performed. All transjugular liver biopsies were performed successfully with adequate tissue for diagnosis. Although specimens obtained by the transjugular technique tended to be shorter (10 mm v. 18 mm by the percutaneous approach, P < 0.001), the presence of fragmentation was similar to that in biopsies obtained by the percutaneous approach. Respectively, 100% and 98% of specimens obtained by the transjugular and percutaneous approaches were considered to be adequate for histological assessment. The clinical impact of transjugular and percutaneous liver procedures was comparable (89% v. 76%, P = 0.25). CONCLUSION: Specimens obtained by a transjugular automated trucut needle are sufficient for histological assessment, and carry clinical impact in patient management.