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Biomedical subjects

Steven S Chin

Publications and source records attributed to Steven S Chin.

15 recordsLinked to original sources
PubMed2007

Neuroradiologic characteristics of astroblastoma.

INTRODUCTION: Astroblastoma is a rare glial tumor of uncertain origin. Only a few scattered case reports and one small case series have described the radiologic appearance of this uncommon tumor. Many features previously identified are similar to those of other primary malignant brain tumors. We report the largest imaging series to date and further delineate the CT and MRI features of astroblastoma. We identify those features that may be useful in distinguishing astroblastoma from other neoplasms. METHODS: The radiologic images, pathology reports, and clinical information of 12 patients with pathology-confirmed astroblastoma were retrospectively reviewed. CT and MRI findings including location, morphology, signal intensity, and presence and patterns of enhancement were tabulated. RESULTS: Patients ranged in age from 0 (newborn) to 50 years with a mean of 20 years at the time of initial diagnosis. A striking female preponderance (11:1) was found. All tumors were supratentorial. There were multiple intratumoral cysts in 7 (58%) of the 12 patients. Nine (75%) showed strong rim enhancement and 3 (25%) showed no rim enhancement. CONCLUSION: The imaging features of astroblastoma are identified in 12 previously unreported cases. Distinguishing features that can be used to narrow the differential diagnosis with more common primary brain neoplasms reflect a combination of age, anatomic location, and specific imaging findings such as demarcation, heterogeneous tumor enhancement, rim enhancement, and a multicystic "bubbly" appearance. Intraventricular location, intratumoral hemorrhage with a fluid-fluid level, and dural "tails" are less common but important additions to the imaging spectrum.

Adolescent↗
PubMed2006

Malignant transformation of conus medullaris ganglioglioma: case report.

Intramedullary gangliogliomas are indolent tumors of the spine with rare cases of malignant transformation. Conus medullaris gangliogliomas are extremely rare but are usually associated with good clinical outcome after gross total resection. We describe the first reported case of a ganglioglioma of the conus medullaris that progressed to glioblastoma multiforme 1 year after subtotal resection and radiotherapy. The paraplegic patient lacked neurological function below the level of the lesion and thus was treated with cordectomy caudal to the root entry zones of the T10 sensory roots.

Adult↗
PubMed2006

An unusual pathologic feature associated with dermatomyositis.

We present a case of juvenile dermatomyositis with unusual histopathologic findings. The child presented with a course consistent with dermatomyositis, a diagnosis confirmed by finding reticulotubular aggregates in endothelial cells on electron microscopy. However, histopathology of his muscle biopsy revealed a striking pattern of glycogen accumulation, to an extent similar to that seen in glycogen storage diseases; this degree of accumulation could potentially confound histopathologic diagnosis.

Biopsy↗
PubMed2006

Glioblastoma multiforme of the pineal region.

Glioblastoma multiforme (GBMs) tumors are exceedingly rare tumors in the pineal region. We present three cases in which patients presented with a pineal/posterior third ventricular region mass and review all the previously reported cases in the literature. Pineal region GBM seems to be a very aggressive tumor with a high rate of leptomeningeal and ependymal metastatic disease. Patients usually present with signs and symptoms of hydrocephalus and Parinaud's syndrome. The clinical and radiological characteristics of pineal GBM do not differentiate it from other malignancies of this region, thus surgical biopsy is generally required for definitive diagnosis. Glioblastoma should be considered in the differential diagnosis of the pineal region tumors, especially when evidence of leptomeningeal or ependymal metastatic disease is present.

Adult↗
PubMed2006

Extraneural metastatic medulloblastoma in an adult.

Medulloblastoma is a rare malignancy in adults, accounting for approximately 1% of all primary brain tumors. Extraneural metastases have been reported in 10-30% of cases and most commonly involve bone; rarely lymph nodes, visceral organs and bone marrow may be involved with disease. We report here our experience with a 26 year-old woman with medulloblastoma treated with gross total resection followed by radiation therapy to her craniospinal axis. She subsequently developed widespread metastatic disease involving bone exclusive of the calvarium and spine for which multi-agent salvage chemotherapy was utilized with initial good clinical response. She later relapsed within the lymph nodes and soft tissues of the pelvis and eventually suffered a local recurrence within the posterior fossa. The treatment of medulloblastoma, particularly salvage therapy following disease recurrence, is reviewed.

Adult↗
PubMed2006

Tuberous sclerosis: a syndrome of incomplete tumor suppression.

Tuberous sclerosis (TS) is a congenital neurocutaneous syndrome (or phacomatosis) characterized by widespread development of hamartomas in multiple organs. For affected individuals, neurological and psychiatric complications are the most disabling and lethal features. Although the clinical phenotype of TS is complex, only three lesions characterize the neuropathological features of the disease: cortical tubers, subependymal nodules, and subependymal giant cell astrocytomas. The latter is a benign brain tumor of mixed neuronal and glial origin. Tuberous sclerosis is caused by loss-of-function mutations in one of two genes, TSC1 or TSC2. The normal cellular proteins encoded by these genes, hamartin and tuberin, respectively, form a heterodimer that suppresses cell growth in the central nervous system by dampening the phosphatidylinositol 3-kinase signal transduction pathway. The authors review the clinical and neuropathological features of TS as well as recent research into the molecular biology of this disease. Through this work, investigators are beginning to resolve the paradoxical findings that malignant cancers seldom arise in patients with TS, even though the signaling molecules involved are key mediators of cancer cell growth.

Animals↗
PubMed2006

Cholesteatoma of the clivus.

Cholesteatomas (central nervous system epidermoids) can be found intradurally or extradurally in the central nervous system. Extradural intraosseous lesions are most commonly found in the petrous bone. The authors describe a unique case of a clival cholesteatoma in a 64-year-old woman who presented with headaches. No other neurological complaints or physical examination findings were noted. Magnetic resonance imaging showed an expansile lesion centered in the middle portion of the clivus. A large portion of the clivus was eroded. The lesion was explored via a transnasal trans-sphenoidal approach and granular debris was evacuated. The cystic lining was stripped from the surrounding bone, and the bone opening was widely fenestrated. Pathological examination showed keratinous debris with macrophages and an outer lining of benign epithelial tissue consistent with a cholesteatoma (epidermoid cyst). When surgically accessible, these lesions should be excised to prevent a recurrence. If inaccessible, marsupialization may be considered.

Case Reports↗
PubMed2005

Small-fiber neuropathy/neuronopathy associated with celiac disease: skin biopsy findings.

BACKGROUND: Celiac disease (CD) is increasingly recognized in North America and is associated with a peripheral neuropathy. OBJECTIVE: To report the clinical characteristics and skin biopsy results in patients with CD and small-fiber neuropathy symptoms. DESIGN: Case series. SETTING: Academic peripheral neuropathy clinic. PATIENTS: Eight patients with CD and neuropathy symptoms. Intervention Three-millimeter punch biopsy using the panaxonal marker protein gene product 9.5 to assess epidermal nerve fiber (ENF) density and a gluten-free diet. MAIN OUTCOME MEASURE: Clinical data and ENF density. RESULTS: All patients had asymmetric numbness and paresthesias. Three had more prominent involvement of hands than feet, and 3 had facial numbness. Celiac disease was diagnosed in 5 after their neuropathy began. The following serum antibody levels were elevated: tissue transglutaminase (n = 6), IgA gliadin (n = 4), and IgG gliadin (n = 7). Results of nerve conduction studies were normal in 7 patients. One patient had mildly reduced sural amplitudes. The ENF density was reduced in 5 patients. The ENF density was at the low limit of the normal range in 3 additional patients, 2 of whom had morphologic changes in axons. Three patients had decreased ENF density at the thigh or forearm, which was more severe than at the distal leg, compatible with a non-length-dependent process. Four reported improvement with a gluten-free diet. One had no improvement after 4 months. Symptoms developed in 2 while receiving a gluten-free diet. CONCLUSIONS: Patients with CD may have a neuropathy involving small fibers, demonstrated by results of skin biopsy. The pattern of symptoms, with frequent facial involvement and a non-length-dependent pattern on skin biopsy findings, suggests a sensory ganglionopathy or an immune-mediated neuropathy. Improvement of symptoms in some patients after initiating a gluten-free diet warrants further study.

Celiac Disease↗
PubMed2005

Creutzfeldt-Jakob disease (CJD) with a mutation at codon 148 of prion protein gene: relationship with sporadic CJD.

Creutzfeldt-Jakob disease (CJD), the most common human prion disease, includes sporadic (s) and familial (f) forms. Regardless of etiology, both forms are thought to share the pathogenic mechanism whereby the cellular prion protein (PrP(C)) converts into its pathogenic isoform (PrP(Sc)). While PrP(C) conversion is thought to be random in sCJD, conversion in fCJD is facilitated by the congenital presence of mutated PrP. Differences in PrP genotype (PRNP) and in conversion circumstances lead to PrP(Sc) with distinct characteristics that elicit different disease phenotypes. Here, we describe a case of fCJD with a substitution of histidine (H) for arginine (R) at codon 148 (R148H) and heterozygosity of the methionine/valine (M/V) polymorphic codon 129, with the 129M allele coupled with the mutation. The disease phenotype and all major characteristics of PrP(Sc) of fCJD(R148H) were virtually indistinguishable from those of sCJDMV2, which has features different from those of any other sCJD. Therefore, despite the differences in etiology, PRNP, and conversion process, the two forms of PrP(Sc) had similar characteristics. Furthermore, comparison of fCJD(R148H) with a recently reported case carrying R148H and homozygosity at codon 129 suggests that codon 129 coupled with the mutation as well as that located on the normal allele can modify major phenotypic and PrP(Sc) features of fCJD(R148H).

Amino Acid Substitution↗
PubMed2005

Unusual findings in brain biopsies of two patients with acute magnetic resonance imaging lesions associated with focal seizures.

PURPOSE: Patients with focal seizures often have magnetic resonance imaging (MRI) abnormalities in the brain region of their presumed seizure focus. Neoplasms, ischemic infarctions, inflammatory processes, and other specific pathologic entities have been diagnosed by biopsies of such MRI abnormalities. Two patients with this presentation had brain lesion biopsies with a leading presumptive diagnosis of glial neoplasm but were found to have indistinct histopathology. METHODS: Each patient was initially seen with focal seizures (right parietal region, right hippocampus) corresponding with focally increased T2 signal on MRI. In both patients, the preoperative clinical suspicion was for neoplastic or inflammatory processes. RESULTS: Several weeks after seizure onset, craniotomy in patient 1 and stereotactic needle biopsy in patient 2 revealed mild gliosis with reactive vascular changes and perivascular hemosiderin deposition, not diagnostic of but compatible with venous congestion (or possibly venous thrombosis). Postoperatively, patient 1 had brief sensory seizures that stopped 5 months after surgery, whereas subsequent seizures did not develop in patient 2. Both patients had normalization of their MRI (except for postoperative changes) and have remained seizure free. CONCLUSIONS: We describe two patients who had brain biopsies of striking focal increased T2 signal MRI abnormalities associated with seizures. Pathologic findings contradicted our preoperative suspicions (neoplasm or inflammatory process), compatible with (but not conclusive for) subacute venous congestion/thrombosis. These findings indicate that patients with seizures may have an associated discrete intraaxial MRI lesion that is not neoplastic. To our knowledge, this is the first report of focal seizure-associated MRI lesions with biopsy findings compatible with venous congestion/thrombosis.

Adult↗
PubMed2005

Temporally regulated neural crest transcription factors distinguish neuroectodermal tumors of varying malignancy and differentiation.

Neuroectodermal tumor cells, like neural crest (NC) cells, are pluripotent, proliferative, and migratory. We tested the hypothesis that genetic programs essential to NC development are activated in neuroectodermal tumors. We examined the expression of transcription factors PAX3, PAX7, AP-2alpha, and SOX10 in human embryos and neuroectodermal tumors: neurofibroma, schwannoma, neuroblastoma, malignant nerve sheath tumor, melanoma, medulloblastoma, supratentorial primitive neuroectodermal tumor, and Ewing's sarcoma. We also examined the expression of P0, ERBB3, and STX, targets of SOX10, AP-2alpha, and PAX3, respectively. PAX3, AP-2alpha, and SOX10 were expressed sequentially in human NC development, whereas PAX7 was restricted to mesoderm. Tumors expressed PAX3, AP-2alpha, SOX10, and PAX7 in specific combinations. SOX10 and AP-2alpha were expressed in relatively differentiated neoplasms. The early NC marker, PAX3, and its homologue, PAX7, were detected in poorly differentiated tumors and tumors with malignant potential. Expression of NC transcription factors and target genes correlated. Transcription factors essential to NC development are thus present in neuroectodermal tumors. Correlation of specific NC transcription factors with phenotype, and with expression of specific downstream genes, provides evidence that these transcription factors actively influence gene expression and tumor behavior. These findings suggest that PAX3, PAX7, AP-2alpha, and SOX10 are potential markers of prognosis and targets for therapeutic intervention.

Biomarkers, Tumor↗
PubMed2004

A pathogenic peripherin gene mutation in a patient with amyotrophic lateral sclerosis.

Peripherin is a neuronal intermediate filament protein that is expressed chiefly in motor neurons and other nerve cells that project into the peripheral nervous system. Transgenic mice that over-express peripherin develop motor neuron degeneration, suggesting that mutations in peripherin could contribute to the development of motor neuron disease. In this paper, we report the identification of a homozygous mutation in the peripherin gene (PRPH) in a patient with amyotrophic lateral sclerosis (ALS). The mutation resulted in a substitution of aspartate with tyrosine at amino acid position 141, which is located within the first linker region of the rod domain. Immunocytochemical analysis of the spinal cord of the patient upon autopsy revealed distinctive large aggregates within the cell bodies of residual spinal motor neurons that contained peripherin and was also immunoreactive with antibodies to the neurofilament proteins. In order to study the effect of the mutation on peripherin assembly, we performed transient transfections. Unlike wild-type peripherin, which self-assembles to form a filamentous network, the mutant peripherin was prone to form aggregates in transfected cells, indicating that the mutation adversely affects peripherin assembly. Moreover, the neurofilament light (NF-L) protein was not able to rescue the mutant protein from forming aggregates. These data imply that mutation of PRPH is a contributing factor for ALS.

Adult↗
PubMed2004

Rectal biopsy in the diagnosis of neuronal intranuclear hyaline inclusion disease.

Neuronal intranuclear hyaline inclusion disease is a neurodegenerative disorder of childhood characterized by eosinophilic intranuclear inclusions and neuronal loss throughout the nervous system. Although most cases have been diagnosed postmortem, rectal biopsy may be diagnostic during life. We identified two patients: an 11-year-old boy (P1) with new-onset bulbar weakness and parkinsonism and a 15-year-old boy (P2) with severe cognitive and motor deterioration of uncertain etiology who presented at 4 years of age with a gait disturbance and motor slowing. Both patients had a history of behavioral problems marked by frequent temper tantrums. Both had nondiagnostic magnetic resonance imaging of the head and metabolic work-ups. Rectal biopsy was diagnostic 1 year (P1) and 11 years (P2) after the initial evaluation. Rectal biopsies should be considered in children presenting with otherwise unexplained multisystem degeneration, particularly in the presence of both upper and lower motoneuron signs accompanied by behavioral problems.

Adolescent↗
PubMed2003

Frontotemporal dementia.

In this case study, we describe the symptoms, neuropsychological testing, and brain pathology of a man with frontotemporal dementia (FTD). FTD most often presents with either a change in personality or behavior, such as social withdrawal, increased gregariousness, disinhibition, or obsessive behaviors; or with impairment of language function. Memory difficulties are common, but usually are less prominent than these other symptoms in the early stages of the disease. Frequently, psychiatric diagnoses are initially the primary consideration. Cases may be either familial or sporadic. In this familial case, an autopsy was ultimately performed and revealed findings characteristic of FTD, with grossly evident focal brain degeneration in the frontal and temporal regions, microscopic signs of gliosis, and cellular abnormalities of the intracellular microtubule-associated protein tau.

Age of Onset↗