Search PubMed⌕ Search

Biomedical subjects

John X O'Connell

Publications and source records attributed to John X O'Connell.

18 recordsLinked to original sources
PubMed2006

Calcific myonecrosis: keys to recognition and management.

OBJECTIVE: Calcific myonecrosis masses can become quite large and worrisome for malignancy. The key to recognition is a combination of radiologic imaging features and remote clinical history of injury associated with compartment syndrome or vascular or neurologic compromise. CONCLUSION: This article will highlight importance of correct diagnosis by identifying the severe and devastating complications following inappropriate management.

Adult↗
PubMed2005

Ligation and partial excision of the cauda equina as part of a wide resection of vertebral osteosarcoma: a case report and description of surgical technique.

STUDY DESIGN: A case report. OBJECTIVES: To describe the unique challenges and novel surgical approach to treatment of vertebral osteosarcoma involving the dura as a margin. SUMMARY OF BACKGROUND DATA: Osteosarcoma of the vertebral column is a rare, malignant osseous tumor, carrying a poor prognosis. Currently, best available evidence supports that optimal surgical treatment entails wide excision of the tumor. Intentionally compromising neurologic function in order to ensure resection of the tumor with wide surgical margins can pose a difficult dilemma for the surgeon and patient. We describe here the first reported case, to our knowledge, of wide surgical resection of a vertebral osteosarcoma, including ligation and resection of part of the cauda equina and conus medullaris. METHODS: The clinical and radiographic presentations of a patient with osteosarcoma of L2 are presented. The challenges of surgical treatment of a primary malignant tumor of the spine, involving the dura as a margin, are discussed. The ultimate surgical technique employed to achieve wide surgical margins is described in detail. RESULTS: Four-year follow-up shows the patient is doing well, ambulating in a wheelchair, with no clinical or radiologic evidence of active disease or back or neuropathic pain and solid bony fusion. CONCLUSION: Currently, there is sufficient evidence to support the premise that the best chance for cure in sarcomas of the spine can be afforded through en bloc resection with negative margins. Neurologic forfeit in resection of spinal tumors, however, is usually at the root level, and this is the only case where such dramatic neurologic sacrifice was carried out. Although it is still early, the surgical and medical goals have been met, but most importantly, the patient's foremost goal of survival has been accomplished.

Adult↗
PubMed2004

Most osteomalacia-associated mesenchymal tumors are a single histopathologic entity: an analysis of 32 cases and a comprehensive review of the literature.

Oncogenic osteomalacia (OO) is a rare paraneoplastic syndrome of osteomalacia due to phosphate wasting. The phosphaturic mesenchymal tumor (mixed connective tissue variant) (PMTMCT) is an extremely rare, distinctive tumor that is frequently associated with OO. Despite its association with OO, many PMTMCTs go unrecognized because they are erroneously diagnosed as other mesenchymal tumors. Expression of fibroblast growth factor-23 (FGF-23), a recently described protein putatively implicated in renal tubular phosphate loss, has been shown in a small number of mesenchymal tumors with known OO. The clinicopathological features of 32 mesenchymal tumors either with known OO (29) or with features suggestive of PMTMCT (3) were studied. Immunohistochemistry for cytokeratin, S-100, actin, desmin, CD34, and FGF-23 was performed. The patients (13 male, 19 female) ranged from 9 to 80 years in age (median 53 years). A long history of OO was common. The cases had been originally diagnosed as PMTMCT (15), hemangiopericytoma (HPC) (3), osteosarcoma (3), giant cell tumor (2), and other (9). The tumors occurred in a variety of soft tissue (21) and bone sites (11) and ranged from 1.7 to 14 cm. Twenty-four cases were classic PMTMCT with low cellularity, myxoid change, bland spindled cells, distinctive "grungy" calcified matrix, fat, HPC-like vessels, microcysts, hemorrhage, osteoclasts, and an incomplete rim of membranous ossification. Four of these benign-appearing PMTMCTs contained osteoid-like matrix. Three other PMTMCTs were hypercellular and cytologically atypical and were considered malignant. The 3 cases without known OO were histologically identical to the typical PMTMCT. Four cases did not resemble PMTMCT: 2 sinonasal HPC, 1 conventional HPC, and 1 sclerosing osteosarcoma. Three cases expressed actin; all other markers were negative. Expression of FGF-23 was seen in 17 of 21 cases by immunohistochemistry and in 2 of 2 cases by RT-PCR. Follow-up (25 cases, 6-348 months) indicated the following: 21 alive with no evidence of disease and with normal serum chemistry, 4 alive with disease (1 malignant PMTMCT with lung metastases). We conclude that most cases of mesenchymal tumor-associated OO, both in the present series and in the reported literature, are due to PMTMCT. Improved recognition of their histologic spectrum, including the presence of bone or osteoid-like matrix in otherwise typical cases and the existence of malignant forms, should allow distinction from other mesenchymal tumors. Recognition of PMTMCT is critical, as complete resection cures intractable OO. Immunohistochemistry and RT-PCR for FGF-23 confirm the role of this protein in PMTMCT-associated OO.

Adolescent↗
PubMed2003

Fibroid in the buttock: an unexpected diagnosis.

Uterine leiomyomas (fibroids) are very common lesions with well-described imaging features. We present an unusual case of a fibroid which presented in the buttock with atypical clinical and imaging features in a woman who had had a previous hysterectomy. Despite extensive imaging and biopsies, the diagnosis was not suspected until pathological evaluation of the resected mass. The differential diagnosis for such a lesion, and the imaging and pathological features of fibroids, including atypical and parasitic leiomyomas, are discussed.

Buttocks↗
PubMed2003

Tissue microarray validation of epidermal growth factor receptor and SALL2 in synovial sarcoma with comparison to tumors of similar histology.

Histological diagnosis of synovial sarcoma can be difficult. Genome-wide expression profiling has identified a number of genes expressed at higher levels in synovial sarcoma than in other soft tissue tumors, representing excellent candidates for diagnostic immunohistochemical markers. A tissue microarray comprising 77 sarcomas, including 46 synovial sarcomas, was constructed to validate identified markers and investigate their expression in tumors in the differential diagnosis of synovial sarcoma. Immunostaining was performed for two such markers, epidermal growth factor receptor and SAL (drosophila)-like 2 (SALL2), and for fifteen established markers used in the differential diagnosis of sarcomas. As predicted by expression profiling, epidermal growth factor receptor (a potential therapeutic target) and SALL2 stained most cases of synovial sarcoma; staining was significantly less common among other tested sarcomas. Hierarchical clustering analysis applied to immunostaining results for all 18 antibodies showed that synovial sarcomas, leiomyosarcomas, hemangiopericytomas, and solitary fibrous tumors cluster distinctly, and assigned one case with indeterminate histology as a Ewing sarcoma. Digital images from over 2500 immunostained cores analyzed in this study were captured and are made accessible through the accompanying website: http://microarray-pubs.stanford.edu/tma_portal/synsarc.

Biomarkers↗
PubMed2003

Novel fluorescent ligase detection reaction and flow cytometric analysis of SYT-SSX fusions in synovial sarcoma.

Synovial sarcomas (SS) are characterized by the t(X;18)(p11;q11) translocation and its resultant fusion gene, SYT-SSX. Two homologues of the SSX gene (ie, SSX1 and SSX2) are involved in the vast majority of SS and the SYT-SSX1 type of fusion has been associated with inferior clinical outcome. Thus, detection of the presence and type of SYT-SSX fusion is critical for diagnosis and prognosis in SS. Identification of SYT-SSX fusion type is typically accomplished by reverse-transcription polymerase chain reaction (RT-PCR) followed by a post-PCR analytic method. As mRNA nucleotide sequences of the SSX1 and SSX2 segments involved in the SYT-SSX fusion are nearly identical, post-PCR methods must be highly discriminatory. We describe a novel method to identify and differentiate these two chimeric transcripts using RT-PCR followed by fluorescent thermostable ligase detection reaction (f-LDR), microparticle bead capture and flow cytometric detection. Evaluation of this unique approach in 11 cases of SS without prior knowledge of SYT-SSX status, six cases of control sarcomas (CS) and three hematopoietic cell lines, revealed that the f-LDR technique was rapid, unambiguous, and highly specific. The f-LDR results were compared to XmnI enzyme digestion patterns and sequencing of PCR products, revealing a 100% concordance for all cases of SS with regards to SYT-SSX transcript type. In addition, there was a strong association of transcript type detected by f-LDR and morphological subclassification of SS, as previously reported. We conclude that this f-LDR method with flow-based detection is a robust approach to post-PCR detection of specific nucleotide sequences in SS and may be more broadly applicable in molecular oncology.

Deoxyribonucleases, Type II Site-Specific↗
PubMed2003

Pathogenesis of orbital cholesterol granuloma.

Two cases are presented of orbital cholesterol granuloma associated with gradual proptosis arising in men aged 35 and 41 years. Computed tomography demonstrated osteo-lytic masses in the frontal bone at the lacrimal fossa. Curettage revealed a characteristic histology of foreign body reactions surrounding cholesterol clefts. In both cases abnormal bone, more consistent with fibrous dysplasia than reactive change, was found at the periphery. The finding of abnormal bone associated with orbital cholesterol granulomas suggests that a pre-existing bone anomaly may be present in a subset of these cases.

Adult↗
PubMed2003

Epithelioid angiosarcoma of the bone: a series of 10 cases.

The clinical and pathologic features of 10 epithelioid angiosarcomas of bone were analyzed. There were eight males and two females who ranged in age from 26 to 83 years (mean 62 years). Four tumors were solitary and six were multifocal. In two consultation cases, the submitted diagnosis was metastatic carcinoma. Microscopically, the tumor cells were arranged in solid and infiltrative sheets, and in most cases vascular channels or cystically dilated spaces were present. The neoplastic cells had abundant eosinophilic cytoplasm and large nuclei with open chromatin and prominent eosinophilic nucleoli. Intratumoral hemorrhage, neutrophilic infiltrates, and intracytoplasmic lumina were frequently present. All 10 tumors stained positive for one or more endothelial markers, with CD31 being the most sensitive marker. Seven cases stained positive for cytokeratin. Ultrastructural examination in three tumors confirmed their endothelial differentiation. In the absence of obvious vascular differentiation, abundant intratumoral hemorrhage and intratumoral neutrophils are useful ancillary morphologic features that may suggest a vascular origin. Six patients are dead of disease, one is alive with metastasis, and two patients are currently disease free. Epithelioid angiosarcoma of bone should be included in the differential diagnosis of epithelioid neoplasms of bone, and endothelial markers should be a part of their immunohistochemical analysis to avoid the misdiagnosis of a metastatic carcinoma because of the significant differences in the treatment and clinical outcomes of these entities.

Adult↗
PubMed2003

Collagen-rich tumors of soft tissues: an overview.

Although relatively common, soft tissue tumors frequently present diagnostic problems for practicing pathologists. Immunohistochemistry has facilitated the diagnosis of many mesenchymal tumors; however, there is considerable overlap in the staining profiles among cells demonstrating fibroblastic and myofibroblastic differentiation. It has been our experience that soft tissue tumors associated with abundant extracellular collagen deposition commonly cause problems in classification. One reason for this is that tumors displaying this morphology include representatives from different histogenetic families. Specifically, tumors exhibiting fibroblastic, myofibroblastic and even lipomatous differentiation may manifest as a densely collagenous mass. It is the purpose of this review to highlight these collagen-rich soft tissue tumors.

Biomarkers, Tumor↗
PubMed2002

Cryptic t(X;18), ins(6;18), and SYT-SSX2 gene fusion in a case of intraneural monophasic synovial sarcoma.

A 54-year-old male presented with a spontaneous peroneal nerve palsy and a diagnosis of monophasic synovial sarcoma (SS) was rendered by histologic examination. Cytogenetic analysis revealed a complex abnormal karyotype without evidence of the typical t(X;18)(p11;q11) associated with SS. Subsequent reverse transcriptase polymerase chain reaction analysis showed the presence of an SYT/SSX2 fusion transcript, confirming the presence of a cyptic t(X;18). In light of -X, -18 and marker chromosomes evident in the G-band karyotype, it was suspected that a cryptic chromosomal rearrangement involving the marker chromosomes would harbor an X;18 fusion. Multi-colored karytotyping (M-FISH) revealed a previously unrecognized t(X;18) and t(5;19) in the marker chromosomes as well as unrecognized ins(6;18) and t(16;20). The addition of M-FISH analysis in this case led to the identification of complex inter-chromosomal rearrangements, thus providing an accurate karyotype.

Chromosome Aberrations↗
PubMed2002

Molecular characterisation of soft tissue tumours: a gene expression study.

BACKGROUND: Soft-tissue tumours are derived from mesenchymal cells such as fibroblasts, muscle cells, or adipocytes, but for many such tumours the histogenesis is controversial. We aimed to start molecular characterisation of these rare neoplasms and to do a genome-wide search for new diagnostic markers. METHODS: We analysed gene-expression patterns of 41 soft-tissue tumours with spotted cDNA microarrays. After removal of errors introduced by use of different microarray batches, the expression patterns of 5520 genes that were well defined were used to separate tumours into discrete groups by hierarchical clustering and singular value decomposition. FINDINGS: Synovial sarcomas, gastrointestinal stromal tumours, neural tumours, and a subset of the leiomyosarcomas, showed strikingly distinct gene-expression patterns. Other tumour categories--malignant fibrous histiocytoma, liposarcoma, and the remaining leiomyosarcomas--shared molecular profiles that were not predicted by histological features or immunohistochemistry. Strong expression of known genes, such as KIT in gastrointestinal stromal tumours, was noted within gene sets that distinguished the different sarcomas. However, many uncharacterised genes also contributed to the distinction between tumour types. INTERPRETATION: These results suggest a new method for classification of soft-tissue tumours, which could improve on the method based on histological findings. Large numbers of uncharacterised genes contributed to distinctions between the tumours, and some of these could be useful markers for diagnosis, have prognostic significance, or prove possible targets for treatment.

Gene Expression Profiling↗
PubMed2002

Ollier's disease in association with adjacent fibromatosis.

Ollier's disease (enchondromatosis) is a nonhereditary disorder of mesodermal dysplasia. It is characterized by the presence of multiple enchondromas that typically affect the metaphyseal ends of bones. The association of Ollier's disease with adjacent fibromatosis has, to our knowledge, not been previously described. We report a case of Ollier's disease in association with soft tissue fibromatosis adjacent to the involved upper arm.

Adult↗
PubMed2002

Coamplification of 12p11 and 12q13 approximately q22 in multiple ring chromosomes in a spindle cell sarcoma resolved by novel multicolor fluorescence in situ hybridization analysis.

An 80-year-old male presented with a lobulated mass in the lower abdominal wall. A diagnosis of an intermediate grade myofibroblastic spindle cell sarcoma was made. Cytogenetic analysis demonstrated a complex karyotype with a der(6), a small marker and five, different in size, ring chromosomes. Fluorescence in situ hybridization (FISH), multiplex FISH, and multicolor banding analysis was used to further delineate this complex karyotype. The der(6) was shown to be a der(18)t(6;18;9;12;18), the marker chromosome was identified as del(17), and the ring chromosomes as r(9) and r(12;18)x4. Amplification of 18 and coamplification of 12p and 12q was detected in the ring and marker chromosomes. No intercellular heterogeneity was observed although a few micronuclei containing chromosome 18 and anaphase bridges, containing chromosome 12 material, the result of bridge-fusion-bridge (BFB) cycles, were observed. Our findings combined with results from others indicate that amplification of chromosomes 12 and 18 as well as BFB phenomena characterize this type of sarcoma.

Chromosome Mapping↗
PubMed2002

Dermatofibrosarcoma protuberans: MR imaging features.

OBJECTIVE: The objective of our study was to describe the MR imaging features of 10 cases of histologically confirmed dermatofibrosarcoma protuberans. CONCLUSION: MR imaging is useful in identifying the extent and location of dermatofibrosarcoma protuberans. Although most cases of this tumor are superficial and well defined, we have shown three cases in which the tumor was in a deep location and one case in which the tumor was ill defined in appearance. Knowledge of the variable MR imaging appearances of these tumors may aid in the diagnosis of difficult or atypical cases.

Adult↗
PubMedDate not supplied

Primary bone tumors of the orbit.

Primary tumors of orbital bone constitute 0.6% to 2% of all orbital tumors. Our experience over a 24-year period in the Orbital Clinic at the University of British Columbia yielded 62 (1.9%) cases from a total of 3,340 orbital tumors. Although a heterogeneous group, primary orbital bone tumors may be classified on a clinicopathologic basis into benign fibro-osseous or cartilaginous, reactive, neoplastic and vascular disorders. Presentation is usually a gradual mass effect, with infiltration and acute hemorrhage being features of malignant and reactive lesions respectively. The two most commonly encountered entities were fibrous dysplasia and osteoma, accounting for 22 cases. Although both these conditions rarely present a diagnostic challenge, nonspecific histologic and radiologic appearances can result in poor characterization of several of the rarer lesions. Hence, close cooperation between clinician, radiologist and pathologist is essential for accurate diagnosis.

Bone Neoplasms↗