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Search Results: 1 - 10 of 297575 matches for " Lester J. Layfield "
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Histopathologic Review of Previously Negative Prostatic Core Needle Biopsies Following a New Diagnosis of Adenocarcinoma of the Prostate by Core Needle Biopsies: Implications for Quality Assurance Programs
Jay Patel and Lester J. Layfield
Clinical Medicine Insights: Pathology , 2012,
Abstract: Programs for quality assurance are increasingly important in surgical pathology. Many quality assurance (QA) techniques for surgical pathology were adopted from procedures introduced in cytopathology. Surgical pathology specimens have diminished in size such that the majority of diagnostic biopsies of prostatic lesions are now core needle biopsies. These specimens raise issues similar to those of cytology specimens, including concerns regarding adequacy and the representative nature of the biopsy. Due to sample size, some neoplasms may not be diagnosed on initial biopsy, raising concerns regarding false negative results. Cytopathologists have instituted QA procedures including review of all previously negative slides received within five years prior to the new diagnosis of high grade squamous intraepithelial lesion or gynecologic malignancy. No such requirement exists in surgical pathology for review of core biopsies. The Department of Pathology at the University of Utah instituted a QA policy requiring review of prior negative prostatic needle biopsies following a new diagnosis of prostatic adenocarcinoma. We reviewed five years of QA records of prostate needle biopsy review. During this time, nine hundred and fifty-eight core biopsy sets were performed. Two hundred and ninety-five of these contained at least one biopsy with a diagnosis of adenocarcinoma. Two hundred and eight patients had a prior set of prostatic needle biopsies with a diagnosis of adenocarcinoma. The remaining 87 had prior biopsies with either a diagnosis of prostatic intraepithelial neoplasia (23), small atypical acinar proliferation (21) or no evidence of malignancy (43). QA review of these 87 cases revealed two biopsies which revealed foci of adenocarcinoma. Both had been initially diagnosed as no evidence of malignancy. The false negative rate for core biopsy was 0.68%. In an additional twenty-one cases, microscopic foci of atypical small acinar proliferations were found in core biopsies antedating the positive core biopsy (7.1%).
Histopathologic Review of Previously Negative Prostatic Core Needle Biopsies Following a New Diagnosis of Adenocarcinoma of the Prostate by Core Needle Biopsies: Implications for Quality Assurance Programs
Jay Patel,Lester J. Layfield
Clinical Medicine : Pathology , 2008,
Abstract: Programs for quality assurance are increasingly important in surgical pathology. Many quality assurance (QA) techniques for surgical pathology were adopted from procedures introduced in cytopathology. Surgical pathology specimens have diminished in size such that the majority of diagnostic biopsies of prostatic lesions are now core needle biopsies. These specimens raise issues similar to those of cytology specimens, including concerns regarding adequacy and the representative nature of the biopsy. Due to sample size, some neoplasms may not be diagnosed on initial biopsy, raising concerns regarding false negative results. Cytopathologists have instituted QA procedures including review of all previously negative slides received within five years prior to the new diagnosis of high grade squamous intraepithelial lesion or gynecologic malignancy. No such requirement exists in surgical pathology for review of core biopsies. The Department of Pathology at the University of Utah instituted a QA policy requiring review of prior negative prostatic needle biopsies following a new diagnosis of prostatic adenocarcinoma. We reviewed five years of QA records of prostate needle biopsy review. During this time, nine hundred and fifty-eight core biopsy sets were performed. Two hundred and ninety-five of these contained at least one biopsy with a diagnosis of adenocarcinoma. Two hundred and eight patients had a prior set of prostatic needle biopsies with a diagnosis of adenocarcinoma. The remaining 87 had prior biopsies with either a diagnosis of prostatic intraepithelial neoplasia (23), small atypical acinar proliferation (21) or no evidence of malignancy (43). QA review of these 87 cases revealed two biopsies which revealed foci of adenocarcinoma. Both had been initially diagnosed as no evidence of malignancy. The false negative rate for core biopsy was 0.68%. In an additional twenty-one cases, microscopic foci of atypical small acinar proliferations were found in core biopsies antedating the positive core biopsy (7.1%).
Classification, Molecular Characterization, and the Significance of Pten Alteration in Leiomyosarcoma
Allie H. Grossmann,Lester J. Layfield,R. Lor Randall
Sarcoma , 2012, DOI: 10.1155/2012/380896
Abstract: Leiomyosarcoma is a malignant smooth muscle neoplasm with a complicated histopathologic classification scheme and marked differences in clinical behavior depending on the anatomic site of origin. Overlapping morphologic features of benign and borderline malignant smooth muscle neoplasms further complicate the diagnostic process. Likewise, deciphering the complex and heterogeneous patterns of genetic changes which occur in this cancer has been challenging. Preliminary studies suggest that reproducible molecular classification may be possible in the near future and new prognostic markers are emerging. Robust recapitulation of leiomyosarcoma in mice with conditional deletion of Pten in smooth muscle and the simultaneous discovery of a novel role for Pten in genomic stability provide a fresh perspective on the mechanism of leiomyosarcomagenesis and promise for therapeutic intervention.
Squamous Differentiation and Cytokeratin Expression in an Osteosarcoma: A Case Report and Review of the Literature
Lester J. Layfield, Lyska Emerson, Julia R. Crim and Lor Randall
Clinical Medicine Insights: Pathology , 2012,
Abstract: Cytokeratin expression has been documented in a variety of sarcomas including synovial sarcomas, epithelioid sarcomas, Ewing’s sarcomas and, rarely, osteosarcomas. In osteosarcomas immunohistochemically shown to expression cytokeratins, a component of epithelioid cells is generally present. These epithelioid cytokeratin positive cells raise the possibility of metastatic disease with prognostic and therapeutic implications differing from primary osteosarcoma. The cytokeratin-expressing cells of the cases reported in the literature have not shown definitive squamous differentiation with keratin pearl formation. We report a case of osteosarcoma in which islands of malignant squamous cells were present showing keratin pearl formation and expression of cytokeratins.
Prognostic Markers in Chondrosarcoma: Evaluation of Cell Proliferation and of Regulators of the Cell Cycle
Sean P. Scully,Lester J. Layfield,John M. Harrelson
Sarcoma , 1997, DOI: 10.1080/13577149778344
Abstract:
Squamous Differentiation and Cytokeratin Expression in an Osteosarcoma: A Case Report and Review of the Literature
Lester J. Layfield,Lyska Emerson,Julia R. Crim,Lor Randall
Clinical Medicine : Pathology , 2008,
Abstract: Cytokeratin expression has been documented in a variety of sarcomas including synovial sarcomas, epithelioid sarcomas, Ewing’s sarcomas and, rarely, osteosarcomas. In osteosarcomas immunohistochemically shown to expression cytokeratins, a component of epithelioid cells is generally present. These epithelioid cytokeratin positive cells raise the possibility of metastatic disease with prognostic and therapeutic implications differing from primary osteosarcoma. The cytokeratin-expressing cells of the cases reported in the literature have not shown definitive squamous differentiation with keratin pearl formation. We report a case of osteosarcoma in which islands of malignant squamous cells were present showing keratin pearl formation and expression of cytokeratins.
Classification, Molecular Characterization, and the Significance of Pten Alteration in Leiomyosarcoma
Allie H. Grossmann,Lester J. Layfield,R. Lor Randall
Sarcoma , 2012, DOI: 10.1155/2012/380896
Abstract: Leiomyosarcoma is a malignant smooth muscle neoplasm with a complicated histopathologic classification scheme and marked differences in clinical behavior depending on the anatomic site of origin. Overlapping morphologic features of benign and borderline malignant smooth muscle neoplasms further complicate the diagnostic process. Likewise, deciphering the complex and heterogeneous patterns of genetic changes which occur in this cancer has been challenging. Preliminary studies suggest that reproducible molecular classification may be possible in the near future and new prognostic markers are emerging. Robust recapitulation of leiomyosarcoma in mice with conditional deletion of Pten in smooth muscle and the simultaneous discovery of a novel role for Pten in genomic stability provide a fresh perspective on the mechanism of leiomyosarcomagenesis and promise for therapeutic intervention. 1. Introduction Smooth muscle tumors constitute a spectrum of diseases with wide-ranging clinical behaviors. In general, clinical behavior correlates with patient age, tumor site, histologic appearance, and stage. Leiomyosarcomas (LMSs), the malignant variety, are less common than their benign counterpart, leiomyomas (LMs), and most frequently occur in middle-aged to elderly adults [1]. Children and adolescents generally do not develop LM or LMS, and those rare neoplasms occurring in this population are typically associated with Epstein Barr virus expression, owing to an immunocompromised state [1–3]. Excluding the extremely rare LMS of bone [3], LMS represents approximately 24% of all sarcomas [4] and is, therefore, one of the most common mesenchymal malignancies. The two most frequent sites of origin are the uterus and retroperitoneum, but LMS has been reported in a variety of soft tissue sites, visceral organs, skin, and bone [2, 3]. The diagnostic histopathologic features of smooth muscle tumors are well defined [2]. Architecturally, LM and well-differentiated LMS are composed of bundles and fascicles of cells, intersecting at perpendicular angles. The smooth muscle cells are typically elongate with abundant eosinophilic cytoplasm, cigar-shaped nuclei, and perinuclear vacuoles. Most well-differentiated lesions stain diffusely for actins (smooth muscle actin or muscle-specific actin), and many also stain for desmin, and h-caldesmon. These markers are not specific for smooth muscle, however, and should be interpreted in the context of appropriate clinical and morphologic features. Up to 38% of LMSs will also stain focally for cytokeratins [5], warranting careful
The National Cancer Institute Thyroid fine needle aspiration state of the science conference: a summation
Baloch Zubair,Cibas Edmund,Clark Douglas,Layfield Lester
CytoJournal , 2008,
Abstract:
On the distribution of the zeros of the derivative of the Riemann zeta-function
S. J. Lester
Mathematics , 2013, DOI: 10.1017/S0305004114000413
Abstract: We establish an unconditional asymptotic formula describing the horizontal distribution of the zeros of the derivative of the Riemann zeta-function. For $\Re(s)=\sigma$ satisfying $(\log T)^{-1/3+\epsilon} \leq (2\sigma-1) \leq (\log \log T)^{-2}$, we show that the number of zeros of $\zeta'(s)$ with imaginary part between zero and $T$ and real part larger than $\sigma$ is asymptotic to $T/(2\pi(\sigma-1/2))$ as $T \rightarrow \infty$. This agrees with a prediction from random matrix theory due to Mezzadri. Hence, for $\sigma$ in this range the zeros of $\zeta'(s)$ are horizontally distributed like the zeros of the derivative of characteristic polynomials of random unitary matrices are radially distributed.
The distribution of the logarithmic derivative of the Riemann zeta-function
S. J. Lester
Mathematics , 2013,
Abstract: We investigate the distribution of the logarithmic derivative of the Riemann zeta-function on the line Re(s)=\sigma, where \sigma, lies in a certain range near the critical line \sigma=1/2. For such \sigma, we show that the distribution of \zeta'/\zeta(s) converges to a two-dimensional Gaussian distribution in the complex plane. Upper bounds on the rate of convergence to the Gaussian distribution are also obtained.
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