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Technological and implant design advances have helped reduce the frequency of aseptic total joint arthroplasty failure, but periprosthetic joint infections (PJI) remain a clinical important problem with high patient morbidity. Misinterpreting PJI as aseptic mechanical loosening commonly leads to unsatisfactory revision arthroplasty, persistent infection, and poor long-term results. While there is no single "gold standard" diagnostic test for PJI, recent collaborative efforts by Orthopaedic and Infectious Disease Societies have developed algorithms for diagnosing PJI. However, the efficacy of individual tests as well as diagnostic thresholds are controversial. We review the recommended thresholds for commonly used screening tests as well as tissue histopathology and confirmatory tests to diagnose periprosthetic infection. We also update lesser-known laboratory tests, and we briefly summarize rapidly evolving molecular tests to diagnose periprosthetic infection. Pathologists hold a critical role in assisting with PJI diagnosis, maintaining laboratory test quality and interpreting test results. Collaboration between clinicians and pathologists is essential to provide optimal patient care and reduce the burden of PJI., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Rapid detection of bloodstream infections (BSIs) can be lifesaving. We investigated the sample processing and assay parameters necessary for highly-sensitive detection of bloodstream bacteria, using Staphylococcus aureus as a model pathogen and an automated fluidic sample processing-polymerase chain reaction (PCR) platform as a model diagnostic system., Methodology/principal Findings: We compared a short 128 bp amplicon hemi-nested PCR and a relatively shorter 79 bp amplicon nested PCR targeting the S. aureus nuc and sodA genes, respectively. The sodA nested assay showed an enhanced limit of detection (LOD) of 5 genomic copies per reaction or 10 colony forming units (CFU) per ml blood over 50 copies per reaction or 50 CFU/ml for the nuc assay. To establish optimal extraction protocols, we investigated the relative abundance of the bacteria in different components of the blood (white blood cells (WBCs), plasma or whole blood), using the above assays. The blood samples were obtained from the patients who were culture positive for S. aureus. Whole blood resulted in maximum PCR positives with sodA assay (90% positive) as opposed to cell-associated bacteria (in WBCs) (71% samples positive) or free bacterial DNA in plasma (62.5% samples positive). Both the assays were further tested for direct detection of S. aureus in patient whole blood samples that were contemporaneous culture positive. S. aureus was detected in 40/45 of culture-positive patients (sensitivity 89%, 95% CI 0.75-0.96) and 0/59 negative controls with the sodA assay (specificity 100%, 95% CI 0.92-1)., Conclusions: We have demonstrated a highly sensitive two-hour assay for detection of sepsis causing bacteria like S. aureus directly in 1 ml of whole blood, without the need for blood culture.

The following abstracts are compiled from Check Sample exercises published in 2008. These peer-reviewed case studies assist laboratory professionals with continuing medical education and are developed in the areas of clinical chemistry, cytopathology, forensic pathology, hematology, microbiology, surgical pathology, and transfusion medicine. Abstracts for all exercises published in the program will appear annually in AJCP.

The diagnosis of granular acute lymphoblastic leukemia (ALL) can be problematic as the cytoplasmic granules found in many blast cells may mimic those seen in acute myelogenous leukemia (AML). This rare variant of B-cell ALL is more commonly diagnosed in children, but may occur in adults. We report a case of granular B-ALL in a 56-year-old female and review the literature.

Recent studies of acute erythroleukemias have reaffirmed DiGuglielmo's syndrome (M6a, myeloblast-predominant) and disease (M6b, pronormoblast-predominant). M6c (mixed myeloblast/pronormoblast) has also been described. However, MDS is still defined according to the percentage of myeloblasts (% myeloblasts) without including the pronormoblast count. A 20-year retrospective study was performed to identify cases demonstrating >or=50% erythrocytic component and <30% calculated blasts (FAB exclusion criteria) without underlying cause (96 cases). Pronormoblast and myeloblast counts and other variables were analyzed as possible explanatory variables of the variations in survival. Considered alone, increasing % myeloblasts and/or percentage of pronormoblasts (% pronormoblasts) were significant predictors of decreasing survival. When all variables were considered as a multivariate group, the best fitting statistical model for predicting survival was a function of age, % pronormoblasts, IPSS cytopenias, platelet count, and percentage erythrocytic component. Of these, % pronormoblasts was by far the most significant. Nonappearance of % myeloblasts in this model is indicative of high correlations of this count with other variables.

Acute erythroleukemia (FAB M6) is a rare heterogeneous disease with an increase in red cell precursors and myeloblasts. Three subsets have been described: M6A (myeloblast-rich erythroleukemia); M6B (proerythroblast-rich erythroleukemia); and M6C (myeloblast- and proerythroblast-rich mixed variant). This study was undertaken to define and compare the clinical courses and survival outcomes among M6A, M6B, and M6C variants of erythroleukemia. Sixty-nine cases of M6 leukemia were categorized as consisting of >/=50% erythroid of all nucleated cells and M6A with >/=30% myeloblasts/nonerythroid component; M6B with >/=30% proerythroblasts/erythroid component; and M6C with >/=30% myeloblasts and >/=30% proerythroblasts. The demographics, cell type distribution, and survival (mean +/- sd) of these groups were compared. There were 32 M6A, 26 M6B, and 11 M6C patients. No significant difference was seen among the groups in age, sex, or treatment. Compared to M6A, both the M6B (P< 0.0001) and M6C (P< 0.0001) variants showed a statistically significant increase in the percentage of bone marrow erythroid cells, proerythroblasts, and the proerythroblasts/erythroid ratios. Comparing the groups for survival, M6B (3 +/- 3.6 months) versus M6A (25 +/- 28 months), P< 0. 002, and M6C (10 +/- 13 months) versus M6A, P< 0.01 had a poorer prognosis. Calculating the proerythroblasts as a component of total bone marrow erythroids provides a complimentary method for delineating the pure red cell erythroleukemia (M6B) and mixed variant (M6C), similar to that for the myeloid/erythroid (M6A) leukemia. Now that it is possible to delineate erythroleukemia subtypes, innovative treatments are indicated to target the malignant erythroid population, which is resistant to myeloid-based therapies., (Copyright 2000 Wiley-Liss, Inc.)

Acute erythroleukemia is a relatively rare disorder of a multilineal nature. Patients with this type of leukemia traditionally have been treated with a standard myeloid protocol, with a wide variation in prognosis between M6a, which has a similar prognosis to acute myelogenous leukemias, and M6b, with an extremely poor outcome despite aggressive therapy. Forty-eight archival cases of acute erythroleukemia, subtypes M6a (the traditional FAB-M6), M6b (pure erythroleukemia), and M6c (>30% myeloblasts and >30% pronormoblasts by FAB exclusion criteria), were evaluated for multidrug resistance gene (MDR-1) status. Findings were correlated with clinical course and karyotypes. Immunohistochemical stain for the protein product of MDR-1, P-glycoprotein, was variably positive in 11 of 23 patients with M6a, as well as in all of the patients with M6b (strongly positive) and M6c (weakly positive). P-glycoprotein expression positively correlated with unfavorable cytogenetic aberrations, poor response to chemotherapeutic agents, and short survival. Most significant was that P-glycoprotein expression demonstrated a negative additive effect on response to treatment and prognosis with unfavorable cytogenetic anomalies. P-glycoprotein expression and multiple cytogenetic anomalies most probably contribute to the resistance to chemotherapy and poor survival characteristic of the patients with M6b (mean survival, 3.15 +/- 4.2 mo) and M6c (mean survival, 10.5 +/- 12.7 mo). Because patients with M6b and M6c have increased numbers of pronormoblasts in their bone marrow and past chemotherapeutic attempts have failed, chemotherapy directed at these cells is appropriate. Additional therapy directed toward the MDR-1 gene and its protein product seems indicated from our findings.

Acute erythroleukemia is an aggressive leukemia derived from a multipotential stem cell. Three subtypes have been described: (1) M6a with greater than or equal to 30% blasts of the nonerythrocytic component, (2) M6b with greater than or equal to 30% pronormoblasts of the erythrocytic elements, and (3) M6c with greater than or equal to 30% blasts and greater than or equal to 30% pronormoblasts by the aforementioned exclusion criteria. The poor prognosis associated with this disorder positively correlates with a high pronormoblast:myeloblast ratio; unfavorable cytogenetic aberrations; a high proliferative index; and the presence of P-glycoprotein expression (multidrug resistance phenotype). Chemotherapeutic regimens directed toward these specific parameters should be devised in order to improve the characteristically poor outcome of this patient population.

We evaluated 48 archival cases of acute erythroleukemia and divided them into 3 groups: M6a, corresponding to the traditional French-American-British M6 category; M6b, which is pure erythroleukemia; and M6c, in which myeloblasts and pronormoblasts each account for more than 30% of cells by the French-American-British exclusion criteria. No significant differences were noted among the subtypes for ratio of males to females; age; or exposure to toxins, alcohol, or both. However, compared with the patients in the M6a group, patients in the M6b and M6c groups demonstrated a statistically significant increase in cytogenetic aberrations, proliferation markers (proliferating cell nuclear antigen and Ki67), and ringed (type III) sideroblasts. Marked survival differences were noted between the M6a (30.1 +/- 29.5 months) and M6b (3.15 +/- 4.2 months) groups, with patients in the M6c group demonstrating an intermediate prognosis (10.5 +/- 12.7 months). Chemotherapeutic regimens induced remission in all treated patients in the M6a and M6c groups but did not appear to affect the M6b group. However, the patients in the M6c group remained in remission for a significantly shorter period of time than did patients in the M6a group. Overall, survival appeared to depend on the ratio of pronormoblasts to myeloblasts at diagnosis and demonstrated a rapid decline with increasing pronormoblast and decreasing myeloblast counts. We must, therefore, devise chemotherapeutic regimens that target both blastic components of this disease.

This is a case of a long-term Connecticut resident who presented with both human granulocytic ehrlichiosis and Lyme disease. The etiologic agents and the probability of coinfection are discussed.

We report a case of mammary duct carcinoma with a prominent lipid-rich, sebaceous-like component, occurring in a 55 yr old white male. The patient presented with a painless, subareolar left breast mass and the diagnosis of malignancy was made by fine needle aspiration. Subsequent modified radical mastectomy revealed an infiltrating and in situ ductal carcinoma with dermal invasion and numerous vacuolated sebaceous-like tumor cells, positive for neutral lipid by Oil Red O stain. We propose that this case represents an unusual variant of lipid-secreting breast carcinoma. To the best of our knowledge, this subtype of mammary carcinoma is unprecedented in male breast.

We report a rare case of testicular histiocytoid hemangioma. Pathological features and differential diagnosis of this neoplasm are discussed.