M. Qasim Ansari

Mesenchymal chondrosarcoma: A clinicopathologic and flow cytometric study of 13 cases presenting in the central nervous system

Mesenchymal chondrosarcomas arising in the central nervous system are extremely rare. Morphologic features have not been found to correlate reliably with prognosis.

De Novo CD5+ Diffuse Large B-Cell Lymphomas A Heterogeneous Group Containing an Unusual Form of Splenic Lymphoma

We reviewed our institutional experience with de novo CD5+, large B-cell lymphomas to determine whether they represent a distinct entity and are related to CD5+ small B-cell disorders. We identified 13 cases with multiparameter flow cytometry over a period of 58 months (5% of large B-cell lymphomas) in 7 females and 6 males. Three groups were identified. Group 1 (2 cases) had diffuse splenic red pulp involvement with a distinctive cordal pattern of infiltration, no other clinical evidence of mass disease, microscopic disseminated disease on further workup, and an identical immunoglobulin-negative immunophenotype. Group 2 cases (7 cases) were clinically and morphologically heterogeneous and had an immunophenotype resembling mantle cell lymphoma (FMC7-positive, CD23-). Group 3 (4 cases) had miscellaneous immunophenotypes, including one closely resembling chronic lymphocytic leukemia. Cyclin D1 was positive in only 1 of 10 evaluable cases (group 2). We conclude that CD5+ diffuse large B-cell lymphomas are heterogeneous; most cases do not seem to be related to chronic lymphocytic leukemia or mantle cell lymphoma. However, we identified a subgroup of primary splenic CD5+ large B-cell lymphoma with diffuse red pulp involvement and believe this may represent a distinct clinicopathologic entity.

Atypical fibroxanthoma: DNA ploidy analysis of 14 cases with possible histogenetic implications.

The histogenesis of atypical fibroxanthoma (AFX) and its relationship to malignant fibrous histiocytoma (MFH) arc a subject of controversy. Many investigators have proposed that AFX may represent a reactive process, while others contend that it is a true fibrohistiocytic neoplasm, closely related to MFH. In an attempt to determine whether biologic differences between AFX and MFH may be accounted for at the cellular DNA level, we performed ploidy analysis on 14 cases of AFX by flow cytometry and compared our results with previously reported DNA analyses of MFH. Thirteen of the 14 lesions demonstrated diploid distribution of nuclear DNA, and only 1 case had an aneuploid population. This contrasts with prior data on MFH, the vast majority of which are aneuploid. Our results suggest that, despite histologic similarities, AFX may be distinguished from MFH on the basis of DNA content. These findings may be significant in understanding the biologic behavior of AFX.

Risk factors associated with false positive HIV test results in a low-risk urban obstetric population

Objective. To examine risk factors for false positive HIV enzyme immunoassay (EIA) testing at delivery. Study Design. A review of pregnant women who delivered at Parkland Hospital between 2005 and 2008 was performed. Patients routinely received serum HIV EIA testing at delivery, with positive results confirmed through immunofluorescent testing. Demographics, HIV, hepatitis B surface antigen (HBsAg), and rapid plasma reagin (RPR) results were obtained. Statistical analyses included Pearsons chi-square and Students t-test. Results. Of 47,794 patients, 47,391 (99%) tested negative, 145 (0.3%) falsely positive, 172 (0.4%) positive, and 86 (0.2%) equivocal or missing HIV results. The positive predictive value of EIA was 54.3%. Patients with false positive results were more likely nulliparous (43% versus 31%, P < 0.001) and younger (23.9 ± 5.7 versus 26.2 ± 5.9 years, P < 0.001). HIV positive patients were older than false positive patients and more likely positive for HBsAg and RPR. Conclusion. False positive HIV testing at delivery using EIA is associated with young maternal age and nulliparity in this population.

The VITROS Immunodiagnostics Products Anti-HIV 1+2 Assay: A Rapid and Reliable Method for HIV Screening

Background: To ensure increased awareness of HIV status by patients, the Centers for Disease Control and Prevention (CDC) has issued new guidelines that greatly expand screening recommendations. The goal of the present study was to assess the overall reliability, sensitivity, specificity, and turnaround time (TAT) of the VITROS Anti-HIV 1+2 Assay (Ortho Clinical Diagnostics, Rochester, NY) in a large community hospital setting. The assay was recently approved by the Food and Drug Administration (FDA). Methods: We compared our current Abbott HIVAB assay (Abbott Laboratories, Abbott Park, IL) with how the VITROS performed on the random access VITROS ECi/ECiQ System in a head-to-head comparison of 298 patient samples and a retrospective comparison of TAT over an 8-month period of utilization. Results: Our data indicate that the VITROS is as sensitive (100%, n=298) and more specific (98% vs 83%) than the Abbott HIVAB and has a faster average TAT (156 minutes vs 1266 minutes). Conclusions: Use of this rapid and reliable assay will lead to greater awareness of HIV status and, hopefully, a decrease in incidence of HIV disease.

Systemic Sclerosis (Scleroderma)

labmedicine.com November 2005 Volume 36 Number 11 LABMEDICINE 723 Systemic sclerosis is a chronic disease of unknown etiology characterized by abnormal accumulation of fibrous tissue in the skin and multiple organs.1 Scleroderma derives its name from the Greek words “sclerosis” (hardness) and “derma” (skin), thus aptly named “hard skin,” a feature that is common to all the different types of scleroderma (Image 1). Over time, it became apparent that the disease was not only “skin deep” but manifested itself systemically and thus became known as “systemic sclerosis.” In clinical practice, 2 distinct categories of systemic sclerosis are considered: (1) diffuse scleroderma, and (2) limited scleroderma. Other categories include the overlap syndromes and localized scleroderma.