David Y Lu

University of California, Los Angeles, Los Ángeles, California, United States

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Publications (10)32.02 Total impact

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    ABSTRACT: Gastrointestinal stromal tumor (GIST) is the most common primary mesenchymal tumor of the gastrointestinal tract. This entity comprises a wide spectrum of tumors that vary from benign to overtly malignant, with the majority of these tumors harboring oncogenic mutations of the KIT receptor tyrosine kinase that can aid in diagnosis as well as in targeted therapy. Although the majority of GISTs are sporadic, there are forms that are associated with a variety of syndromes including Carney-Stratakis syndrome and neurofibromatosis type 1, as well as a subset of familial GIST syndromes that are caused by germline mutations in KIT or PDGFRA. Here, we describe an unusual case of a patient who was found to have a large abdominal GIST with an incidentally found Xp11 translocation-associated renal carcinoma. The karyotype of the renal carcinoma revealed an unbalanced rearrangement involving an (X;22) translocation at Xp11.2 and 22p11.2, which has not been reported in the literature. Although GISTs have shown an association with other primary malignant neoplasms, including simultaneous presence with unilateral clear cell renal cell carcinoma and bilateral papillary renal cell carcinomas, we describe the first reported case of synchronous GIST and Xp11 translocation-associated renal cell carcinoma.
    Preview · Article · Aug 2015
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    ABSTRACT: The objective of this study was to determine the characteristics of prostate cancer foci missed on 3-T multiparametric MRI performed with an endorectal coil. The MRI examinations of 122 patients who underwent 3-T multiparametric MRI of the prostate with an endorectal coil were compared with whole-mount histopathology obtained after radical prostatectomy. The mean age of the patients was 60.6 years (SD, 7.6 years), and the mean prostate-specific antigen value was 7.2 ng/mL (SD, 5.9 ng/mL). The clinical, multiparametric MRI (i.e., T2-weighted imaging, diffusion-weighted imaging, and dynamic contrast-enhanced imaging), and histopathologic features were obtained. After an independent review, two blinded genitourinary radiologists matched each case with a genitourinary pathologist. A structured reporting system was used to classify the multiparametric MRI features of each MRI-detected lesion. A chi-square analysis was performed for categoric variables, and the t test was performed for continuous variables. On whole-mount histopathology, 285 prostate cancer foci were detected in 122 patients. Of the 285 cancer foci detected at histopathology, 153 (53.3%) were missed on MRI and 132 (46.7%) were detected on MRI. Of the missed lesions, 75.2% were low-grade prostate cancer. Multiparametric MRI had a significantly higher sensitivity for prostate cancer foci 1 cm or larger than for subcentimeter foci (81.1% vs 18.9%, respectively; p < 0.001), for lesions with a Gleason score of 7 or greater than for lesions with a Gleason score of 6 (72.7% vs 27.3%; p < 0.01), and for index lesions than for satellite lesions (80.3% vs 20.8%; p < 0.01). The 3-T multiparametric MRI examinations showed a higher detection rate for lesions in the midgland or base of the gland compared with lesions in the apex (52.3% vs 22.0%, respectively; p < 0.01). Compared with the prostate cancer lesions that were detected on multiparametric MRI, the prostate cancer lesions that were missed were significantly smaller, were more likely to be low-grade lesions (i.e., Gleason score of 6), were more commonly satellite lesions, and were more likely to be located in the prostatic apex.
    Full-text · Article · Jul 2015 · American Journal of Roentgenology
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    ABSTRACT: Abstract: PD44-10 Date & Time: Session Title: Prostate Cancer: Detection and Screening IV Sources of Funding: None Introductions and Objectives Multiparametric magnetic resonance imaging (MP-MRI) has become increasingly popular to evaluate prostate cancer (CaP). Our objective was to correlate diameter of tumor region of interest (ROI) on prostate MP-MRI with diameter of concordant foci at whole mount histopathology (WMHP) stratified by PI-RADS and Gleason Score(GS). Methods A HIPPA-compliant, IRB approved study of 254 consecutive men who underwent prostate MP-MRI before radical prostatectomy (RP) was performed. MP-MRI and WMHP features were obtained. The index tumor was defined as the lesion with the highest GS or largest tumor if multiple foci had the identical GS. A genitourinary radiologist and pathologist reviewed each case to match each MRI ROI to the concordant foci on WMHP. Maximal diameter of corresponding tumor measured on WMHP and MRI. Correlation scatter plots were drawn and Pearson correlation coefficient rho(ρ) was calculated to determine strength of correlation between size of tumors stratified by GS and PI-RADS. A p-value of 0.05 was considered significant. Results The 254 patients had 279 CaP foci on WMHP matched with MP-MRI ROIs concordantly. The 201 tumors out of 279 were index tumors. Of 279 CaP foci, GS was 6(3+3) in 79 (28.31%), 7(3+4) in 117 (41.94%), 7(4+3) in 50 (17.92%) and ≥8 in 33(11.83%). Of 279 CaP foci, overall PI-RADS of ROI at MR was 2 in 28 (10.04%), 3 in 113 (40.50%), 4 in 84 (30.11%) and 5 in (19.35%). The Pearson correlation coefficient (ρ) between the MR tumor diameter size and the WMHP size was 0.45 and 0.49 for total tumors and index tumors respectively (p<0.05). The rho between the tumor diameter on MR and WMHP are 0.42, 0.67 and 0.61 for tumors with GS=3+4, GS=4+3 and GS≥8 respectively (p<0.05). Rho was 0.28, 0.52 and 0.73 for tumors with overall PI-RADS of 3, 4 and 5 respectively (p<0.05). Conclusions Size of index and non-index tumors on MP-MRI correlates with WMHP. This correlation becomes stronger for lesions with higher PI-RADS or Gleason Scores. However, true size is consistently underestimated. Authors Khoshnoodi, Pooria (Los Angeles, CA); Khoshnoodi, Pooria; Tan, Nelly; Tan, Nelly; Margolis, Daniel J. A.; Margolis, Daniel J. A.; Lin, Wei-Chan; Lin, Wei-Chan; Thamtorawat, Somrach; Thamtorawat, Somrach; Lu, David Y.; Lu, David Y.; Huang, Jiaoti; Huang, Jiaoti; Reiter, Robert E.; Reiter, Robert E.; Raman, Steven S.; Raman, Steven S. \ https://www.auanet.org/university/abstract_detail.cfm?id=PD44-10&meetingID=15NOLA
    Preview · Conference Paper · Apr 2015
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    ABSTRACT: Purpose We explored the impact of magnetic resonance imaging-ultrasound fusion prostate biopsy on the prediction of final surgical pathology. Materials and Methods A total of 54 consecutive men undergoing radical prostatectomy at UCLA after fusion biopsy were included in this prospective, institutional review board approved pilot study. Using magnetic resonance imaging-ultrasound fusion, tissue was obtained from a 12-point systematic grid (mapping biopsy) and from regions of interest detected by multiparametric magnetic resonance imaging (targeted biopsy). A single radiologist read all magnetic resonance imaging, and a single pathologist independently rereviewed all biopsy and whole mount pathology, blinded to prior interpretation and matched specimen. Gleason score concordance between biopsy and prostatectomy was the primary end point. Results Mean patient age was 62 years and median prostate specific antigen was 6.2 ng/ml. Final Gleason score at prostatectomy was 6 (13%), 7 (70%) and 8–9 (17%). A tertiary pattern was detected in 17 (31%) men. Of 45 high suspicion (image grade 4–5) magnetic resonance imaging targets 32 (71%) contained prostate cancer. The per core cancer detection rate was 20% by systematic mapping biopsy and 42% by targeted biopsy. The highest Gleason pattern at prostatectomy was detected by systematic mapping biopsy in 54%, targeted biopsy in 54% and a combination in 81% of cases. Overall 17% of cases were upgraded from fusion biopsy to final pathology and 1 (2%) was downgraded. The combination of targeted biopsy and systematic mapping biopsy was needed to obtain the best predictive accuracy. Conclusions In this pilot study magnetic resonance imaging-ultrasound fusion biopsy allowed for the prediction of final prostate pathology with greater accuracy than that reported previously using conventional methods (81% vs 40% to 65%). If confirmed, these results will have important clinical implications.
    No preview · Article · Nov 2014 · The Journal of Urology
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    ABSTRACT: Multiparametric magnetic resonance imaging (mp-MRI) is increasingly used in prostate cancer (CaP). Understanding the limitations of tumor detection, particularly in multifocal disease, is important in its clinical application.
    Full-text · Article · Sep 2014 · European Urology
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    ABSTRACT: PURPOSE To determine the characteristics of prostate cancer foci missed by mulit-parametric MRI. METHOD AND MATERIALS A HIPPA-compliant, IRB-approved retrospective study of 122 patients with multi-parametric prostate MRI were compared to whole mount prostate obtained after a radical prostatectomy was performed between October 2010 and January 2013 was performed. Clinical (age, PSA, biopsy), MR imaging (T2, DWI, DCE and MRSI), and pathologic features (Gleason Score, size of tumor, pathological stage, extracapsular extension) were obtained. A GU radiologist and pathologist collectively reviewed each case and matched the MR lesion to whole-mount pathology lesion. A standardized classification system (Pi-RADS) was used to characterize the multi-parametric MR features based on Linkert scale (1-5). Chi-square analysis was performed for categorical variable and t-test for continuous variable. A p-value of 0.05 was considered significant. RESULTS 122 patients had 284 unique prostate tumor foci. 149 (52.5%) prostate cancer foci in 74 patients were missed by MRI. 111 (74.5%) were GS6 followed by 23 (15.4%) GS 3+4, 9 (6.0%) GS4+3, 6 (4.0%)GS 8-10. Missed CaP foci were smaller in size (0.8 vs 1.8 cm, p=0.001), had higher proportion of GS6 (74 vs 28%) and lower proportion of GS3+4 (15 vs 40%), GS4+3 (6 vs 21%), GS8-10 (4 vs 10%), compared to CaP that were detected by MR. Missed CaP had higher proportion localized to one segment of the prostate-- apex (30 v 10%), mid (37 v 18%), base(9 v 5%)-- and lower proportion of foci crossing multiple segments--apex to base (3 v 20%), apex to mid (11 vs 26%), mid to base (10 v 22%)-- compared to detected CaP lesions (p=0.0001). There was no difference in use of endorectal coil (87 vs 86%, p=0.86), PSA (7.7 v 7.1, p=0.44) or prostate volume (41 vs 45, p=0.12) between detected and missed CaP. CONCLUSION Prostate CaP foci missed on MRI were smaller in maximal diameter, higher in proportion of low-grade tumors (GS6), were localized to one segment of the prostate instead of crossing multiple segments compared to prostate foci detected by MR. CLINICAL RELEVANCE/APPLICATION Our findings has implications for the use of standard systematic prostate biopsies in addition to MR-based targeted biopsy for full characterization of tumor burden.
    No preview · Conference Paper · Dec 2013
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    ABSTRACT: Accurate determination of HER2/neu status in breast carcinoma is essential. Alteration of preanalytic variables is known to affect HER2/neu results. American Society of Clinical Oncology (ASCO) and the College of American Pathologists (CAP) issued guidelines to standardize fixation for increased HER2/neu accuracy. We studied the effects of changing preanalytic variables on HER2/neu immunohistochemical and fluorescence in situ hybridization (FISH) results in a known HER2/neu+ invasive carcinoma. The clinical specimen was processed according to ASCO/CAP guidelines, with remaining tumor stored fresh without any fixatives for 4 days at 4°C and cut into core biopsy-sized pieces. Each was fixed in 10% formalin, 15% formalin, Pen-Fix (Richard-Allan Scientific, Kalamazoo, MI), Bouin solution, Sakura molecular fixative (Sakura Tissue-Tek Xpress, Torrance, CA), or zinc formalin for 0 to 168 hours. Immunohistochemical studies and FISH were performed. Compared with the clinical specimen, the samples showed no tumor degradation or marked difference by immunohistochemical studies, except the 1-hour 10% formalin and Bouin samples, or FISH, except the Bouin-fixed samples. Our study demonstrates that HER2/neu results remain accurate beyond ASCO/CAP-recommended preanalytic variables, with the exception of Bouin solution for FISH analysis.
    Preview · Article · Nov 2011 · American Journal of Clinical Pathology
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    ABSTRACT: Extracardiac rhabdomyomas are rare benign entities that usually occur in the head and neck region. Although genital rhabdomyoma is known to occur in the lower genital tract of young and middle-aged women, involvement of the anatomically adjacent urethra by rhabdomyoma is exceedingly rare. We present a case of genital rhabdomyoma arising from the urethra of an infant girl. The tumor was characterized by the submucosal presence of mature-appearing rhabdomyoblastic cells containing conspicuous cross-striations, with the cells set in a collagenous stroma. Necrosis and mitoses were absent. Skeletal muscle differentiation of the tumor cells was supported by positive immunohistochemical staining for desmin and myogenin. To our knowledge, this is the first case of urethral genital-type rhabdomyoma in a child.
    No preview · Article · Oct 2011 · Human pathology
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    ABSTRACT: Temporomandibular joint (TMJ) problems are usually the result of functional disorders. Tumors of the TMJ are rarer entities, the diagnosis of which may be delayed due to a clinical impression of a functional ailment. We report a case of a patient with a recurrent TMJ area lesion diagnosed cytologically as pigmented villonodular synovitis (PVNS), an entity that very rarely involves the TMJ and is usually diagnosed by histology. The differential diagnosis of PVNS in the context of its location in and around the TMJ is also discussed. Diagn. Cytopathol. 2011;39:45–48. © 2010 Wiley-Liss, Inc.
    No preview · Article · Jan 2011 · Diagnostic Cytopathology
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    ABSTRACT: PURPOSE/AIM The purpose of this exhibit is: 1. To review the different fibroepithelial lesions in the spectrum of fibroadenoma to phyllodes tumor, including conventional fibroadenoma, cellular fibroadenoma, benign phyllodes, borderline phyllodes, and malignant phyllodes. 2. To highlight the imaging characteristics of each subtype, and how they correlate with pathology findings. 3. To review the appropriate workup and management of these lesions. CONTENT ORGANIZATION Overview of lesions in the continuum from fibroadenoma to phyllodes tumor, and their histological differences. Review of imaging findings for each lesion type with mammography, ultrasound, and MRI. Correlation of imaging findings with pathology findings. Workup and management of each lesion type. SUMMARY Fibroadenomas, a type of fibroepithelial lesion, are the most common solid mass in women of all ages. Imaging, as well as tissue sampling, are vital aspects of management when fibroepithelial lesions begin to demonstrate concerning features. After viewing this exhibit, viewers should: 1. Become familiar with the different subtypes of fibroepithelial lesions within the breast. 2. Be able to recognize salient imaging findings for these lesions, and how they correlate with pathology findings. 3. Understand the management and treatment for each of these subtypes.
    No preview · Conference Paper ·