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Open science practices are research tools used to improve research quality and transparency. These practices have been used by researchers in various medical fields, though the usage of these practices in the surgical research ecosystem has not been quantified. In this work, we studied the use of open science practices in general surgery journals. Eight of the highest-ranked general surgery journals by SJR2 were chosen and their author guidelines were reviewed. From each journal, 30 articles published between January 1, 2019 and August 11, 2021 were randomly chosen and analyzed. Five open science practices were measured (preprint publication prior to peer-reviewed publication, use of Equator guidelines, study protocol preregistration prior to peer-reviewed publication, published peer review, and public accessibility of data, methods, and/or code). Across all 240 articles, 82 (34%) used one or more open science practices. Articles in theInternational Journal of Surgeryshowed greatest use of open science practices, with a mean of 1.6 open science practices compared to 0.36 across the other journals (p

Background At many trauma centers in the United States, one acute care surgeon is responsible for overnight coverage of both the emergency general surgery (EGS) and trauma services. The impact of this scheduling phenomenon on the quality and safety of trauma care has not been studied. Methods Overnight (12:00 AM to 7:00 AM) trauma admissions to an academic Level 1 trauma center from 2013-2015 were studied after the institution adopted this scheduling phenomenon. Admissions were divided into two groups based on whether the admitting surgeon covered only the trauma service, or both the trauma and EGS services ("multi-service coverage"). Four major outcomes (e.g., mortality and complications), six quality metrics (e.g., time to first odds ratio visit and unplanned transfers to the ICU), and procedural utilization patterns were compared. Results A total of 1046 admissions were included. There were no differences in any major outcomes between the two exposure groups, including any National Trauma Data Bank-defined complication (OR 1.1, 95% CI 0.8-1.5, P= 0.5). Quality metrics dependent on the admitting surgeon remained unchanged, including attending presence at the highest-level trauma activations within 15 min of arrival (93% versus 86%, P= 0.07) and time to urgent operative intervention (68 min versus 82 min, P= 0.9). There were no differences in the number of laboratory and imaging studies (4.1 versus 4.1, P= 0.9) or bedside interventions (1.8 versus 2.1, P= 0.4) performed per patient by the admitting surgeon. Multivariate logistic regression did not identify multi-service coverage as an independent risk factor for adverse patient outcomes or quality metrics. Conclusions Trauma admissions under a surgeon covering multiple services simultaneously had similar outcomes, quality metrics, and procedural utilization patterns compared to trauma admissions under surgeons covering only the trauma service. Despite concerns that multiple-service coverage may overburden one acute care surgeon, time-dependent quality metrics and studies done during the initial workup of trauma patients remained unchanged. These findings suggest that simultaneous trauma and EGS service coverage by one acute care surgeon does not adversely impact trauma patient care.

While acute kidney injury (AKI) is a common complication in COVID-19, data on post-AKI kidney function recovery and the clinical factors associated with poor kidney function recovery is lacking.A retrospective multi-centre observational cohort study comprising 12,891 hospitalized patients aged 18 years or older with a diagnosis of SARS-CoV-2 infection confirmed by polymerase chain reaction from 1 January 2020 to 10 September 2020, and with at least one serum creatinine value 1-365 days prior to admission. Mortality and serum creatinine values were obtained up to 10 September 2021.Advanced age (HR 2.77, 95%CI 2.53-3.04, p 0.0001), severe COVID-19 (HR 2.91, 95%CI 2.03-4.17, p 0.0001), severe AKI (KDIGO stage 3: HR 4.22, 95%CI 3.55-5.00, p 0.0001), and ischemic heart disease (HR 1.26, 95%CI 1.14-1.39, p 0.0001) were associated with worse mortality outcomes. AKI severity (KDIGO stage 3: HR 0.41, 95%CI 0.37-0.46, p 0.0001) was associated with worse kidney function recovery, whereas remdesivir use (HR 1.34, 95%CI 1.17-1.54, p 0.0001) was associated with better kidney function recovery. In a subset of patients without chronic kidney disease, advanced age (HR 1.38, 95%CI 1.20-1.58, p 0.0001), male sex (HR 1.67, 95%CI 1.45-1.93, p 0.0001), severe AKI (KDIGO stage 3: HR 11.68, 95%CI 9.80-13.91, p 0.0001), and hypertension (HR 1.22, 95%CI 1.10-1.36, p = 0.0002) were associated with post-AKI kidney function impairment. Furthermore, patients with COVID-19-associated AKI had significant and persistent elevations of baseline serum creatinine 125% or more at 180 days (RR 1.49, 95%CI 1.32-1.67) and 365 days (RR 1.54, 95%CI 1.21-1.96) compared to COVID-19 patients with no AKI.COVID-19-associated AKI was associated with higher mortality, and severe COVID-19-associated AKI was associated with worse long-term post-AKI kidney function recovery.Authors are supported by various funders, with full details stated in the acknowledgement section.

Admissions are generally classified as COVID-19 hospitalizations if the patient has a positive SARS-CoV-2 polymerase chain reaction (PCR) test. However, because 35% of SARS-CoV-2 infections are asymptomatic, patients admitted for unrelated indications with an incidentally positive test could be misclassified as a COVID-19 hospitalization. Electronic health record (EHR)-based studies have been unable to distinguish between a hospitalization specifically for COVID-19 versus an incidental SARS-CoV-2 hospitalization. Although the need to improve classification of COVID-19 versus incidental SARS-CoV-2 is well understood, the magnitude of the problems has only been characterized in small, single-center studies. Furthermore, there have been no peer-reviewed studies evaluating methods for improving classification.The aims of this study are to, first, quantify the frequency of incidental hospitalizations over the first 15 months of the pandemic in multiple hospital systems in the United States and, second, to apply electronic phenotyping techniques to automatically improve COVID-19 hospitalization classification.From a retrospective EHR-based cohort in 4 US health care systems in Massachusetts, Pennsylvania, and Illinois, a random sample of 1123 SARS-CoV-2 PCR-positive patients hospitalized from March 2020 to August 2021 was manually chart-reviewed and classified as "admitted with COVID-19" (incidental) versus specifically admitted for COVID-19 ("for COVID-19"). EHR-based phenotyping was used to find feature sets to filter out incidental admissions.EHR-based phenotyped feature sets filtered out incidental admissions, which occurred in an average of 26% of hospitalizations (although this varied widely over time, from 0% to 75%). The top site-specific feature sets had 79%-99% specificity with 62%-75% sensitivity, while the best-performing across-site feature sets had 71%-94% specificity with 69%-81% sensitivity.A large proportion of SARS-CoV-2 PCR-positive admissions were incidental. Straightforward EHR-based phenotypes differentiated admissions, which is important to assure accurate public health reporting and research.

Background With an increasing number of therapeutic options available for the management of ulcerative colitis (UC), the variability in treatment and prescribing patterns is not well known. While recent guidelines have provided updates on how these therapeutic options should be used, patterns of long-term use of these drugs over the past 2 decades remain unclear. Methods We analyzed a retrospective, nationwide cohort of more than 1.7 million prescriptions for trends in prescribing behaviors and to evaluate practices suggested in guidelines relating to ordering biologics, step-up therapy, and combination therapy. The primary outcome was 30-day steroid-free remission and secondary outcomes included hospitalization, cost, and additional steroid usage. A pipeline was created to identify cohorts of patients under active UC medical management grouped by prescribing strategies to evaluate comparative outcomes between strategies. Cox proportional hazards and multivariate regression models were utilized to assess postexposure outcomes and adjust for confounders. Results Among 6 major drug categories, we noted major baseline differences in patient characteristics at first exposure corresponding to disease activity. We noted earlier use of biologics in patient trajectories (762 days earlier relative to UC diagnosis, 2018 vs 2008; P < .001) and greater overall use of biologics over time (2.53× more in 2018 vs 2008; P < .00001) . Among biologic-naive patients, adalimumab was associated with slightly lower rates of remission compared with infliximab or vedolizumab (odds ratio, 0.92; P < .005). Comparisons of patients with early biologic initiation to patients who transitioned to biologics from 5-aminosalicylic acid suggest lower steroid consumption for early biologic initiation (-761 mg prednisone; P < .001). Combination thiopurine-biologic therapy was associated with higher odds of remission compared with biologic monotherapy (odds ratio, 1.36; P = .01). Conclusions As biologic drugs have become increasingly available for UC management, they have increasingly been used at earlier stages of disease management. Large-scale analyses of prescribing behaviors provide evidence supporting early use of biologics compared with step-up therapy and use of thiopurine and biologic combination therapy.

Many U.S. institutions have adopted postsurgical opioid-prescribing guidelines to standardize prescribing practices, and yet there is inherent variability in patients' opioid consumption after surgery. The utility of these guidelines is limited by the fact that some patients' needs will inevitably exceed them, and yet there are no evidence-based tools to help providers identify these patients. In this study we aimed to maximize the value of these guidelines by training machine learning models to predict patients whose needs will be met by these smaller recommended prescriptions, and patients who may require an additional degree of personalization. The aim of the present study was to develop predictive models for determining whether a surgical patient's postdischarge opioid requirement will fall above or below common opioid prescribing guidelines.We conducted a retrospective cohort study of surgical patients at one institution from 2017 to 2018. Patients were called after discharge to collect opioid consumption data. Machine learning models were used to identify outlier opioid consumers (ie, exceeding our institutional prescribing guidelines) using diagnosis codes, medical history, in-hospital opioid use, and perioperative factors as predictors. External validation was performed on opioid consumption data collected at a second institution from 2020 to 2021, and sensitivity analysis was performed using a third institution's prescribing guidelines.The development and external validation cohorts included 1,867 and 498 patients, respectively. Age, body mass index, tobacco use, preoperative opioid exposure, and in-hospital opioid consumption were the strongest predictors of postdischarge consumption. A lasso regression model exhibited an area under the receiver operating characteristic curve of 0.74 (95% confidence interval 0.67-0.81) in predicting postdischarge opioid consumption. External validation of a limited lasso model yielded an area under the receiver operating characteristic curve of 0.67 (0.60-0.74). Performance was preserved when evaluated on another institution's guidelines (area under the receiver operating characteristic curve 0.76 [0.72-0.80]).Patient characteristics reliably predict postdischarge opioid consumption in relation to prescribing guidelines for both opioid-naive and exposed populations. This model may be used to help providers confidently follow prescribing guidelines for patients with typical opioid responsiveness and correctly pursue more personalized prescribing for others.

Background The Plastic Surgery Milestones Project was implemented in 2014 to establish standards for competency based resident education. In restructuring educational activities under the Milestones, various pedagogical tools have been revised. However, these standards have not yet been applied to the Plastic Surgery In-Service Training Examination. The purpose of this study was to determine the representation of the various components of the Plastic Surgery Milestones Project, on the In-Service Training Examination. Methods All questions from the 2014 ‐ 2018 In-Service Examinations were evaluated within the framework of the current Plastic Surgery Milestones. Using content analysis, each Examination question was mapped to a single Milestone. Descriptive analysis of Milestone subject area and Core Competency breakdown, as well as year to year trends, were performed. Results Of the 1,150 questions analyzed, there was an unequal representation of individual Milestones (0-7.4%). Of the 36 Plastic Surgery Milestones, 10 represented more than 50% of the PSITEs while 8 Milestones had less than 1% representation. The most common subject area was Head and Neck (12.7%) and least common was Reconstruction of the Trunk and Perineum. Among Core Competencies, more than half (50.4%) tested Patient Care while Interpersonal and Communication Skills was the lowest represented, 0.2%. Conclusions The Plastic Surgery In-Service Examination tests a variable proportion of Milestones. Currently, the PSITE is not well integrated with competency based education in spite of a shift towards such a training model. Going forward, the PSITE may include an associated Milestone with each question in order to better incorporate Competencies into this important annual evaluation metric.

BackgroundPost-discharge opioid consumption is an important source of data in guiding appropriate opioid prescribing guidelines, but its collection is tedious and requires significant resources. Furthermore, the reliability of post-discharge opioid consumption surveys is unclear. Our group developed an automated short messaging service (SMS)-to-web survey for collecting this data from patients. In this study, we assessed its effectiveness in estimating opioid consumption by performing causal adjustment and comparison to a phone-based survey as reference.MethodsPatients who underwent surgical procedures at our institution from 2019-2020 were sent an SMS message with a link to a secure web survey to quantify opioids consumed after discharge. Several patient factors extracted from the EHR were tested for association with survey response. Following targeted learning (TL) nonresponse adjustment using these EHR-based factors, opioid consumption survey results were compared to a prior telephone-based survey at our institution as a reference.Results6,553 patients were included. Opioid consumption was measured in 2,883 (44%), including 1,342 (20.5%) through survey response. Characteristics associated with inability to measure opioid consumption included age, length of stay, race, tobacco use, and missing preoperative assessment. Among the top 10 procedures by volume, EHR-based TL nonresponse bias adjustment corrected the median opioid consumption reported by an average of 57%, and corrected the 75th percentile of reported consumption by an average of 11%. This brought median estimates for 6/10 procedures closer to telephone survey-based consumption estimates, and 75th percentile estimates for 3/10 procedures closer to telephone survey-based consumption estimates.ConclusionWe found that applying electronic health record (EHR)-based machine learning nonresponse bias adjustment is essential for debiased opioid consumption estimates from patient surveys. After adjustment, post-discharge surveys can generate reliable opioid consumption estimates. Clinical factors from the EHR combined with TL adjustment appropriately capture differences between responders and nonresponders and should be used prior to generalizing or applying opioid consumption estimates to patient care.

The US health care system is experiencing a sharp increase in opioid-related adverse events and spending, and opioid overprescription may be a key factor in this crisis. Ambient opioid exposure within households is one of the known major dangers of overprescription.To quantify the association between the postsurgical initiation of prescription opioid use in opioid-naive patients and the subsequent prescription opioid misuse and chronic opioid use among opioid-naive family members.This cohort study was conducted using administrative data from the database of a US commercial insurance provider with more than 35 million covered individuals. Participants included pairs of patients who underwent surgery from January 1, 2008, to December 31, 2016, and their family members within the same household. Data were analyzed from January 1 to November 30, 2018.Duration of opioid exposure and refills of opioid prescriptions received by patients after surgery.Risk of opioid misuse and chronic opioid use in family members were calculated using inverse probability weighted Cox proportional hazards regression models.The final cohort included 843 531 pairs of patients and family members. Most pairs included female patients (445 456 [52.8%]) and male family members (442 992 [52.5%]), and a plurality of pairs included patients in the 45 to 54 years age group (249 369 [29.6%]) and family members in the 15 to 24 years age group (313 707 [37.2%]). A total of 3894 opioid misuse events (0.5%) and 7485 chronic opioid use events (0.9%) occurred in family members. In adjusted models, each additional opioid prescription refill for the patient was associated with a 19.2% (95% CI, 14.5%-24.0%) increase in hazard of opioid misuse in family members. The risk of opioid misuse appeared to increase only in households in which the patient obtained refills. Family members in households with any refill had a 32.9% (95% CI, 22.7%-43.8%) increased adjusted hazard of opioid misuse. When patients became chronic opioid users, the hazard ratio for opioid misuse among family members was 2.52 (95% CI, 1.68-3.80), and similar patterns were found for chronic opioid use.This cohort study found that opioid exposure was a household risk. Family members of a patient who received opioid prescription refills after surgery had an increased risk of opioid misuse and chronic opioid use.

Purpose Technology has enhanced modern health care delivery, particularly through accessibility to health information and ease of communication with tools like mobile device messaging (texting). However, text messaging has created new risks for breach of protected health information (PHI). In the current study, we sought to evaluate hand surgeons' knowledge and compliance with privacy and security standards for electronic communication by text message. Methods A cross-sectional survey of the American Society for Surgery of the Hand membership was conducted in March and April 2016. Descriptive and inferential statistical analyses were performed of composite results as well as relevant subgroup analyses. Results A total of 409 responses were obtained (11% response rate). Although 63% of surgeons reported that they believe that text messaging does not meet Health Insurance Portability and Accountability Act of 1996 security standards, only 37% reported they do not use text messages to communicate PHI. Younger surgeons and respondents who believed that their texting was compliant were statistically significantly more like to report messaging of PHI (odds ratio, 1.59 and 1.22, respectively). Discussion A majority of hand surgeons in this study reported the use of text messaging to communicate PHI. Of note, neither the Health Insurance Portability and Accountability Act of 1996 statute nor US Department of Health and Human Services specifically prohibits this form of electronic communication. To be compliant, surgeons, practices, and institutions need to take reasonable security precautions to prevent breach of privacy with electronic communication. Clinical relevance Communication of clinical information by text message is not prohibited under Health Insurance Portability and Accountability Act of 1996, but surgeons should use appropriate safeguards to prevent breach when using this form of communication.

Recent studies have linked postoperative serum troponin elevation to mortality in a range of different clinical scenarios. To date, there has been no investigation into the significance of preoperative troponin elevation in emergency general surgery (EGS) patients. We define this as preoperative myocardial injury (PMI). We hypothesize that PMI seen in EGS patients may predict postoperative morbidity and mortality.Using the American College of Surgeons (ACS) National Surgical Quality Improvement Program (NSQIP) database, we performed a retrospective review of all EGS cases between 2008 and 2014. Patients with preoperative troponin I drawn were compared.There were 464 EGS patients who had troponin I measurements preoperatively. Eighty-two (18%) had preoperative troponin elevations. Patients with PMI were more likely to have the following preoperative physiologic derangements: acute renal failure (18% vs 4%; p = 0.002) and septic shock (40% vs 13%; p0.001). Patient comorbidities associated with PMI included congestive heart failure (13% vs 3%; p = 0.007), dialysis dependence (16% vs 3%; p = 0.002), and American Society of Anesthesiologists (ASA) class ≥ 4 (52% vs 29%; p0.001). Compared with controls, patients with PMI had higher rates of postoperative events (77% vs 52%; p0.001) and mortality (34% vs 13%; p = 0.009). Univariate analysis showed that patients with PMI had an increased risk of postoperative events (odds ratio [OR] 3.02; 95% CI 1.74 to 5.25) and mortality (OR 3.53; 95% CI 1.66 to 7.47). Multivariate analysis revealed preoperative troponin I elevation was an independent predictor of mortality (OR 3.03; 95% CI 1.19 to 7.72, p = 0.020).Emergency general surgery patients with PMI are at increased risk for postoperative events and death. Preoperative myocardial injury is an independent predictor of mortality and has prognostic utility that can prepare surgical teams for adverse events so that they can be recognized, evaluated, and treated earlier.

Objective As a result of the Milestones Project, all Accreditation Council for Graduate Medical Education accredited training programs now use an evaluation framework based on outcomes in 6 core competencies. Despite their widespread use, the Milestones have not been broadly evaluated. This study sought to examine program director (PD) perceptions of the Milestones Project. Design, Setting, and Participants A national survey of general surgery PDs distributed between January and March of 2016. Results A total of 132 surgical PDs responded to the survey (60% response rate). Positive perceptions included value for education (55%) and evaluation of resident performance (58%), as well as ability of Milestones to provide unbiased feedback (55%) and to identify areas of resident deficiency (58%). Meanwhile, time input and the ability of Milestones to discriminate underperforming programs were less likely to be rated positively (25% and 21%, respectively). Half of PDs felt that the Milestones were an improvement over their previous evaluation system (55%). Conclusions Using the Milestones as competency-based, developmental outcomes measures, surgical PDs reported perceived benefits for education and objectivity in the evaluation of resident performance. The overall response to the Milestones was generally favorable, and most PDs would not return to their previous evaluation systems. To improve future iterations of the Milestones, many PDs expressed a desire for customization of the Milestones’ content and structure to allow for programmatic differences.

Mesenchymal chondrosarcoma, a rare malignant round cell and hyaline cartilage tumor, is most commonly intraosseous but can occur in extraskeletal sites. We intensively observed the morphology and applied Sox9 (master regulator of chondrogenesis), beta-catenin (involved in bone formation, thought to inhibit chondrogenesis in a Sox9-dependent manner), and osteocalcin (a marker for osteoblastic phenotype) to 22 central nervous system and musculoskeletal mesenchymal chondrosarcoma. Cases of mesenchymal chondrosarcoma were retrieved and reviewed from our files. Immunohistochemistry and follow-up were obtained on mesenchymal chondrosarcoma and tumor controls. Twenty-two mesenchymal chondrosarcomas included 5 central nervous system (all female; mean age, 30.2; mean size, 7.8 cm; in frontal lobe [n = 4] and spinal cord [n = 1]) and 17 musculoskeletal (female-male ratio, 11:6; mean age, 31.1; mean size, 6.2 cm; 3 each of humerus and vertebrae; 2 each of pelvis, rib, tibia, neck soft tissue; one each of femur, unspecified bone, and elbow soft tissue). The hyaline cartilage in most tumors revealed a consistent linear progression of chondrocyte morphology, from resting to proliferating to hypertrophic chondrocytes. Sixty-seven percent of cases demonstrated cell death and acquired osteoblastic phenotype, cells positive for osteocalcin at the site of endochondral ossification. Small round cells of mesenchymal chondrosarcoma were negative for osteocalcin. SOX9 was positive in both components of 21 of 22 cases of mesenchymal chondrosarcoma. beta-Catenin highlighted rare nuclei at the interface between round cells and hyaline cartilage in 35% cases. Control skull and central nervous system cases were compared, including chondrosarcomas and small cell osteosarcoma, the latter positive for osteocalcin in small cells. Mesenchymal chondrosarcoma demonstrates centrally located hyaline cartilage with a linear progression of chondrocytes from resting to proliferative to hypertrophic, which undergoes endochondral ossification, recapitulating growth plate cartilage and suggesting that this component of mesenchymal chondrosarcoma may be a differentiated (benign or metaplastic) component of a malignant metastasizing tumor. This hyaline cartilage component is morphologically different from cartilage of control chondrosarcoma. Mesenchymal chondrosarcoma can be separated from small cell osteosarcoma, using Sox 9 for cartilage and osteocalcin for osteoblastic phenotype. Rare nuclear beta-catenin expression at the interface between hyaline cartilage and small round cells potentially implicates the APC/Wnt pathway during endochondral ossification in morphologically benign hyaline cartilage component of mesenchymal chondrosarcoma.

In 2011, the ACGME limited duty hours for residents. Although studies evaluating the 2011 policy have not shown improvements in general measures of morbidity or mortality, these outcomes might not reflect changes in specialty-specific practice patterns and secondary quality measures.All trauma admissions from July 2009 through June 2013 at an academic Level I trauma center were evaluated for 5 primary outcomes (eg, mortality and length of stay), and 10 secondary quality measures and practice patterns (eg, operating room [OR] visits). All variables were compared before and after the reform (July 1, 2011). Piecewise regression was used to study temporal trends in quality.There were 11,740 admissions studied. The reform was not strongly associated with changes in any primary outcomes except length of stay (7.98 to 7.36 days; p = 0.01). However, many secondary quality metrics changed. The total number of OR and bedside procedures per admission (6.72 to 7.34; p0.001) and OR visits per admission (0.76 to 0.91; p 0.001) were higher in the post-reform group, representing an additional 9,559 procedures and 1,584 OR visits. Use of minor bedside procedures, such as laboratory and imaging studies, increased most significantly.Although most major outcomes were unaffected, quality of care might have changed after the reform. Indeed, a consistent change in resource use patterns was manifested by substantial post-reform increases in measures such as bedside procedures and OR visits. No secondary quality measures exhibited improvements strongly associated with the reform. Several factors, including attending oversight, might have insulated major outcomes from change. Our findings show that some less-commonly studied quality metrics related to costs of care changed after the 2011 reform at our institution.

Soft tissue Rosai-Dorfman disease (STRDD) is rare, previously reported only as single cases and few series. Simian virus 40 (SV40), a polyomavirus, has been identified in lymphoid processes and has a controversial role in neoplasia etiology. Occasional cytoplasmic pink granular inclusions and nuclear changes led us to explore a viral etiology. Only unpublished STRDD from our files with adequate material, soft tissue location, and diagnostic confirmation were included. Immunohistochemistry and follow-up were obtained. Eighteen STRDD patients, 4 male and 14 female, had 29 lesions; 5 with 2 or more lesions. Ages ranged from 8 to 81 years (mean 42.6 years and median 42.5 years). Soft tissue Rosai-Dorfman disease locations include trunk or proximal extremity (n = 19), distal extremity (n = 5), "abdominal" (n = 3), face (n = 1), and unknown subcutaneous site (n = 1). Sizes ranged from 0.5 to 13.7 cm (median, 2.4 cm). Previous disease included lymphoma, buttocks injection site, diabetes and hypothyroidism, and radiation for chronic dermopathy. No patients had a preceding or concurrent known viral infection; none had lymphadenopathy at present. None were known to be immunocompromised. Soft tissue Rosai-Dorfman disease was rapidly progressing. Initial pathologic diagnosis ranged from Rosai-Dorfman disease or inflammatory pseudotumor to inflammatory malignant fibrous histiocytoma. Grossly STRDDs were multilobulated, tan-yellow, and firm; morphologically, circumscribed, and subcutaneous-based. All had sheets of polygonal histiocytes with abundant pale eosinophilic cytoplasm, emperipolesis, plasma cells, and lymphocytes scattered and within clusters. Focal spindle cell change and mild pleomorphism were each observed in 3 patients; 2 had focal necrosis, none with mitoses. Small granular pink cytoplasmic inclusions and nuclear viral-like changes were observed. By immunohistochemistry, all STRDDs were positive for S100 protein, negative for CD1a, Epstein-Barr virus, and latent membrane protein, yet 3 (all abdominal, 1 multicentric) of the 9 studied were focally positive for cytoplasmic and nuclear SV40 polyomavirus. All were treated by local excision. Follow-up on 14 patients older than 8 to 16 years revealed recurrence in 3 patients with persistent multiple lesions, one with abdominal location. There were no metastases or death from disease. Soft tissue Rosai-Dorfman disease is a rapidly evolving, mostly solitary and nonrecurrent trunk and proximal extremity subcutaneous lesion in middle-aged females. More than one third can have persistent multicentric disease. It is important to recognize STRDD, to separate it from malignancy. Epstein-Barr virus/latent membrane protein was negative but polyomavirus was positive in 3 patients with abdominal STRDD, one with multicentric persistent disease. The relationship of polyomavirus to the evolution of abdominal STRDD should be further explored.

Mesenchymal chondrosarcoma is a rare malignant tumor in the differential diagnosis of other small, round blue cell tumors, including atypical teratoid tumor in the central nervous system (CNS) and rhabdomyosarcoma in the musculoskeletal (MSK) locations. We reviewed the morphology of CNS and MSK cases and applied a panel of immunostains. Archival cases were pulled from our files. Immunohistochemistry and follow-up were obtained. Twenty-two cases included 5 CNS (all female; mean age, 30.2) and 17 MSK (11 female and 6 male; mean age, 31.1). Both CNS and MSK examples had similar round cells, staghorn vascular pattern, increased mitotic activity, and centrally located hyaline cartilage islands. The CNS examples demonstrated more spindling and the MSK cases more necrosis. INI1 was retained in all tumors studied. Epithelial membrane antigen (EMA) and desmin were expressed focally in 35% and 50% of cases, respectively. The round cells of all cases were negative for MyoD1, myogenin, smooth muscle actin (SMA), glial fibrillary acid protein (GFAP), keratins, and estrogen receptor, as well as a panel of other antiobodies. Eighty percent of patients with follow-up had pulmonary metastases and/or died within a mean of 5 years. The CNS and MSK mesenchymal chondrosarcoma predominantly affects adult females with poor prognosis. There are only subtle morphologic differences between the CNS and MSK groups. By immunohistochemistry, mesenchymal chondrosarcoma occasionally expresses aberrant desmin and EMA but is negative for SMA, myogenin MyoD1, GFAP, and keratins, refuting true smooth or skeletal muscle, epithelial, or meningothelial phenotype. Retained INI1 separates these tumors from atypical teratoid tumor. Despite marked female predominance in our series, estrogen receptor is negative in mesenchymal chondrosarcoma.