Pediatric patients with lysosomal acid lipase deficiency / Pacientes pediátricos con deficiencia de lipasa ácida lisosomal

Lysosomal acid lipase (LAL) deficiency is a rare, autosomal recessive disease caused by mutations in the LIPA gene, which produces cholesteryl ester and triglyceride accumulation predominantly in hepatocytes, adrenal glands, and gastrointestinal tract. We describe two new cases occurring in siblings, aged 5 and 7 years, who presented with hepatomegaly, dyslipidemia, and abnormal liver function. Percutaneous liver biopsy revealed portal inflammation, hypertrophic Kupffer cells with a foamy appearance and microvesicular steatosis with fibrosis. Immunostaining for lysosomal markers, cathepsin D and LAMP1 reflected the lysosomal nature of the lipid vacuoles. After enzymatic confirmation, enzyme replacement therapy was initiated for both siblings. Follow-up transaminase levels and lipid profiles showed a notable decrease in AST and ALT and a slight increase in HDL cholesterol. It is crucial to increase awareness of this rare condition among clinicians and pathologists. The expression of lysosomal markers around the lipid vacuoles might help diagnose LAL deficiency in pediatric patients.(AU)

La deficiencia de lipasa ácida lisosomal (LAL) es una enfermedad autosómica recesiva inusual, causada por mutaciones en el gen LIPA, que genera acumulación de éster de colesterol y triglicéridos predominantemente en hepatocitos, glándulas suprarrenales y tracto gastrointestinal. Describimos 2 casos adicionales que ocurrieron en 2 hermanos, de 5 y 7 años, que presentaron hepatomegalia, dislipidemia y función hepática anormal. La biopsia hepática percutánea reveló inflamación portal leve, células de Kupffer hipertróficas, con un aspecto espumoso y esteatosis microvesicular difusa con fibrosis. La inmunotinción de marcadores lisosomales, catepsina D y LAMP1, reflejó la naturaleza lisosomal de las vacuolas lipídicas. Después de la confirmación enzimática, ambos hermanos iniciaron terapia de reemplazo enzimático. Los niveles de transaminasas y los perfiles lipídicos de seguimiento mostraron una disminución notoria en AST y ALT y un ligero aumento en el colesterol HDL. Es crucial aumentar la conciencia de esta inusual condición entre médicos y patólogos. La expresión de marcadores lisosomales alrededor de las vacuolas lipídicas podría ayudar a diagnosticar la deficiencia de LAL en pacientes pediátricos.(AU)

Pediatric patients with lysosomal acid lipase deficiency.

Lysosomal acid lipase (LAL) deficiency is a rare, autosomal recessive disease caused by mutations in the LIPA gene, which produces cholesteryl ester and triglyceride accumulation predominantly in hepatocytes, adrenal glands, and gastrointestinal tract. We describe two new cases occurring in siblings, aged 5 and 7 years, who presented with hepatomegaly, dyslipidemia, and abnormal liver function. Percutaneous liver biopsy revealed portal inflammation, hypertrophic Kupffer cells with a foamy appearance and microvesicular steatosis with fibrosis. Immunostaining for lysosomal markers, cathepsin D and LAMP1 reflected the lysosomal nature of the lipid vacuoles. After enzymatic confirmation, enzyme replacement therapy was initiated for both siblings. Follow-up transaminase levels and lipid profiles showed a notable decrease in AST and ALT and a slight increase in HDL cholesterol. It is crucial to increase awareness of this rare condition among clinicians and pathologists. The expression of lysosomal markers around the lipid vacuoles might help diagnose LAL deficiency in pediatric patients.

Quantification and visualization of anterior pelvis bone density to optimize screw fixation: A novel technique.

Plate fixation of anterior pelvic ring fractures is often a vital component when surgically treating unstable pelvis fractures. Certain plate and screw configurations can have premature implant loosening, potentially in part due to insufficient pullout strength in lower density bone. This study sought to define densities about the anterior pelvic ring using a novel computer-based technique. Thirty-three patients who received a computed tomography (CT) of the abdomen/pelvis for reasons other than pelvis fracture in a 1-month time period were included. Three statistically distinct density regions of the anterior pelvis were identified based on the three-dimensional (3D) density map. The densest regions included both the anterior and posterior aspects of the superior pubic ramus, along with the region of bone along the inferior cotyloid fossa. The intermediate density region included the caudal and medial pubic body. The least dense region included the anterior aspect of the inferior pubic ramus (IPR), the posterior pubic body, and the posterior/inferior IPR. This study presents specific quantification of anterior pelvis bone density based on a novel technique using opportunistic CT scans. Clinical Significance: Anterior surgical fixation of unstable pelvic ring injuries may benefit from targeting areas of higher density as described in this novel technique.

Detectability of Small Low-Attenuation Lesions With Deep Learning CT Image Reconstruction: A 24-Reader Phantom Study.

BACKGROUND. Iterative reconstruction (IR) techniques are susceptible to contrast-dependent spatial resolution, limiting overall radiation dose reduction potential. Deep learning image reconstruction (DLIR) may mitigate this limitation. OBJECTIVE. The purpose of our study was to evaluate low-contrast detectability performance and radiation-saving potential of a DLIR algorithm in comparison with filtered back projection (FBP) and IR using a human multireader noninferiority study design and task-based observer modeling. METHODS. A dual-phantom construct, consisting of a low-contrast detectability module (21 low-contrast hypoattenuating objects in seven sizes [2.4-10.0 mm] and three contrast levels [-15, -10, -5 HU] embedded within liver-equivalent background) and a phantom, was imaged at five radiation exposures (CTDIvol range, 1.4-14.0 mGy; size-specific dose estimate, 2.5-25.0 mGy; 90%-, 70%-, 50%-, and 30%-reduced radiation levels and full radiation level) using an MDCT scanner. Images were reconstructed using FBP, hybrid IR (ASiR-V), and DLIR (TrueFidelity). Twenty-four readers of varying experience levels evaluated images using a two-alternative forced choice. A task-based observer model (detectability index [d']) was calculated. Reader performance was estimated by calculating the AUC using a noninferiority method. RESULTS. Compared with FBP and IR methods at routine radiation levels, DLIR medium and DLIR high settings showed noninferior performance through a 90% radiation reduction (except DLIR medium setting at 70% reduced level). The IR method was non-inferior to routine radiation FBP only for 30% and 50% radiation reductions. No significant difference in d' was observed between routine radiation FBP and DLIR high setting through a 70% radiation reduction. Reader experience was not correlated with diagnostic accuracy (R2 = 0.005). CONCLUSION. Compared with FBP or IR methods at routine radiation levels, certain DLIR algorithm weightings yielded noninferior low-contrast detectability with radiation reductions of up to 90% as measured by 24 human readers and up to 70% as assessed by a task-based observer model. CLINICAL IMPACT. DLIR has substantial potential to preserve contrast-dependent spatial resolution for the detection of hypoattenuating lesions at decreased radiation levels in a phantom model, addressing a major shortcoming of current IR techniques.

Prevalence of SARS-CoV-2 infection and SARS-CoV-2-specific antibody detection among healthcare workers and hospital staff of a university hospital in Colombia.

Objective: The aim of this study was to determine current and previous SARS-COV-2 infection, and describe risk factors associated with seropositivity, among HCWs and hospital staff between June and October of 2020. Methodology: Data from the day of enrollment for a prospective cohort study were analyzed to determine point prevalence and seroprevalence of SARS-CoV-2 infection in HCWs and hospital staff of a university hospital in Colombia. Respiratory samples were collected to perform RT-PCR tests, along with blood samples to measure SARS-CoV-2 IgM and IgG antibodies. Data on nosocomial and community risk factors for infection were also collected and analyzed. Findings: 420 HCWs and hospital staff members were included. The seroprevalence at baseline was 23.2%, of which 10.7% had only IgM antibodies, 0.7% had IgG, and 11.7% had IgM and IgG. The prevalence of acute SARS-CoV-2 infection was 1.9%. Being a nurse assistant was significantly associated with seropositivity when compared with all other job duties (PR 2.39, 95% CI 1.27-3.65, p = 0.01). Conclusions: Overall SARS-CoV-2 prevalence was 1.9% and seroprevalence was 23.15%. Nurse assistants, medical doctors or students, and laboratory workers had a higher possibility of being SARS-CoV-2 seropositive.

A Method for Reducing Variability Across Dual-Energy CT Manufacturers in Quantification of Low Iodine Content Levels.

BACKGROUND. Clinical use of the dual-energy CT (DECT) iodine quantification technique is hindered by between-platform (i.e., across different manufacturers) variability in iodine concentration (IC) values, particularly at low iodine levels. OBJECTIVE. The purpose of this study was to develop in an anthropomorphic phantom a method for reducing between-platform variability in quantification of low iodine content levels using DECT and to evaluate the method's performance in patients undergoing serial clinical DECT examinations on different platforms. METHODS. An anthropomorphic phantom in three body sizes, incorporating varied lesion types and scanning conditions, was imaged with three distinct DECT implementations from different manufacturers at varying radiation exposures. A cross-platform iodine quantification model for correcting between-platform variability at low iodine content was developed using the phantom data. The model was tested in a retrospective series of 30 patients (20 men, 10 women; median age, 62 years) who each underwent three serial contrast-enhanced DECT examinations of the abdomen and pelvis (90 scans total) for routine oncology surveillance using the same three DECT platforms as in the phantom. Estimated accuracy of phantom IC values was summarized using root-mean-square error (RMSE) relative to known IC. Between-platform variability in patients was summarized using root-mean-square deviation (RMSD). RMSE and RMSD were compared between platform-based IC (ICPB) and cross-platform IC (ICCP). ICPB was normalized to aorta and portal vein. RESULTS. In the phantom study, mean RMSE of ICPB across platforms and other experimental conditions was 0.65 ± 0.18 mg I/mL compared with 0.40 ± 0.08 mg I/mL for ICCP (38% decrease in mean RMSE; p < .05). Intrapatient between-platform variability across serial DECT examinations was higher for ICPB than ICCP (RMSD, 97% vs 88%; p < .001). Between-platform variability was not reduced by normalization of ICPB to aorta (RMSD, 97% vs 101%; p = .12) or portal vein (RMSD, 97% vs 97%; p = .81). CONCLUSION. The developed cross-platform method significantly decreased between-platform variability occurring at low iodine content with platform-based DECT iodine quantification. CLINICAL IMPACT. With further validation, the cross-platform method, which has been implemented as a web-based app, may expand clinical use of DECT iodine quantification, yielding meaningful IC values that reflect tissue biologic viability or treatment response in patients who undergo serial examinations on different platforms.

Accuracy of Dual-Energy Computed Tomography Techniques for Fat Quantification in Comparison With Magnetic Resonance Proton Density Fat Fraction and Single-Energy Computed Tomography in an Anthropomorphic Phantom Environment.

OBJECTIVE: To investigate in an anthropomorphic phantom study the accuracy of dual-energy computed tomography (DECT) techniques for fat quantification in comparison with magnetic resonance (MR) proton density fat fraction (PDFF) and single-energy computed tomography (SECT), using known fat content as reference standard. METHODS: Between August 2018 and November 2020, organic material-based cylinders, composed of mixtures of lean and fat tissues mimics, iodine, and iron, were constructed to simulate varying fat content levels (0%, 10%, 15%, 25%, 50%, 75%, and 100%) in a parenchymal organ and were embedded into an anthropomorphic phantom simulating 3 patient sizes (circumference, 91, 126, and 161 cm). The phantom was imaged with multiecho MR, DECT, and SECT. Magnetic resonance PDFF, DECT fat fraction, and computed tomography (CT) numbers (SECT polychromatic and DECT monochromatic data, virtual unenhanced images) were estimated. Performances of MR PDFF and CT techniques to detect differences in fat content were measured using the area under the curve (AUC). Noninferiority of each CT technique relative to MR PDFF was tested using a noninferiority margin of -0.1. RESULTS: MR PDFF, DECT 140 keV monochromatic data, and fat fraction most closely correlated with known fat content (R2 = 0.98, 0.98, and 0.96, respectively). Unlike SECT and all other DECT techniques, DECT fat fraction was not affected by presence of iodine (mean difference, 0.3%; 95% confidence interval [CI], -0.9% to 1.5%). Dual-energy computed tomography fat fraction showed noninferiority to MR PDFF in detecting differences of 5% in fat content in medium-sized phantoms (ΔAUC, -0.05; 95% CI, -0.08 to -0.01), and 7% in large (ΔAUC, -0.04; 95% CI, -0.0 to 0.00) or extralarge sized phantoms (ΔAUC, -0.02; 95% CI, -0.07 to 0.00). CONCLUSIONS: Dual-energy computed tomography fat fraction shows linear correlation with true fat content in the range up to 50% fat fraction. Dual-energy computed tomography fat fraction has comparable estimation error and shows noninferiority to MR PDFF in detecting small differences in fat content across different body sizes.

Carcinoma of the rete testis: A rare testicular tumor.

Carcinoma of the rete testis is a rare malignant tumor which frequently occurs in middle-aged to older patients and has an aggressive biological behavior. We present the case of a 57-year-old man who presented with an ill-defined mass in the right testicle. The patient underwent a radical orchidectomy. Microscopic evaluation showed a neoplasm displaying a complex papillary-cystic architecture, infiltrating the testicular parenchyma. An in situ proliferation of neoplastic cells, with nuclear stratification and scanty cytoplasm was seen at the periphery, within the channels of the rete testis. The tumor infiltrated the tunica albuginea focally without disrupting it completely. Immunohistochemistry was positive for AE1/AE3, CK7, CK34ßE12, D2-40, and PAX8. Imaging studies presented no evidence of metastatic disease. These findings are those of a primary rete testis carcinoma. The transition between benign and neoplastic rete testis epithelium served as a helpful diagnostic clue. Metastatic carcinomas from other sites were considered in the differential diagnosis.

Virtual Unenhanced Dual-Energy CT Images Obtained with a Multimaterial Decomposition Algorithm: Diagnostic Value for Renal Mass and Urinary Stone Evaluation.

Background Virtual unenhanced (VUE) images obtained by using a dual-energy CT (DECT) multimaterial decomposition algorithm hold promise for diagnostic use in the abdomen in lieu of true unenhanced (TUE) images. Purpose To assess VUE images obtained from a DECT multimaterial decomposition algorithm in patients undergoing renal mass and urinary stone evaluation. Materials and Methods In this retrospective Health Insurance Portability and Accountability Act-compliant study, DECT was performed in patients undergoing evaluation for renal mass or urinary stone. VUE images were compared quantitatively to TUE images and qualitatively assessed by four independent radiologists. Differences in attenuation between VUE and TUE images were summarized by using 95% limits of agreement. Diagnostic performance in urinary stone detection was summarized by using area under the receiver operating characteristic curve, sensitivity, and specificity. Results A total of 221 patients (mean age ± standard deviation, 61 years ± 14; 129 men) with 273 renal masses were evaluated. Differences in renal mass attenuation between VUE and TUE images were within 3 HU for both enhancing masses (95% limits of agreement, -3.1 HU to 2.7 HU) and nonenhancing cysts (95% limits of agreement, -2.9 HU to 2.5 HU). Renal mass classification as enhancing mass versus nonenhancing cyst did not change (reclassification rate of enhancing masses, 0% [0 of 78]; 95% CI: 0, 5; reclassification rate of nonenhancing cysts, 0% [0 of 193]; 95% CI: 0, 2) with use of VUE in lieu of TUE images. Among 166 urinary stones evaluated, diagnostic performance of VUE images for stone detection was lower compared with that of TUE images (area under the receiver operating characteristic curve, 0.79 [95% CI: 0.73, 0.84] vs 0.93 [95% CI: 0.91, 0.95]; P < .001) due to reduced sensitivity of VUE for detection of stones 3 mm in diameter or less compared with those greater than 3 mm (sensitivity, 23% [25 of 108; 95% CI: 12, 40] vs 88% [126 of 144; 95% CI: 77, 94]; P < .001). Conclusion Compared with true unenhanced images, virtual unenhanced (VUE) images were unlikely to change renal mass classification as enhancing mass versus nonenhancing cyst. Diagnostic performance of VUE images remained suboptimal for urinary stone detection due to subtraction of stones 3 mm or less in diameter. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Sosna in this issue.

Through-the-Glass Portable Radiography of Patients in Isolation Units: Experience During the COVID-19 Pandemic.

OBJECTIVE. To reduce staff exposure to infection and maintain operational efficiency, we have developed a protocol to image patients using portable chest radiography through the glass of an isolation room. This technique is safe and easy to implement. Images are of comparable quality to standard portable radiographs. CONCLUSION. This protocol, used routinely by our department during the COVID-19 pandemic, can be applied to any situation in which the patient is placed in isolation.

Colitis actínica de localización cecal. Serie de casos / Actinic colitis of cecal location. Number of cases

Resumen Por definición, la colitis actínica incluye cambios inflamatorios de la mucosa colorrectal secundarios a radioterapia en cercanía a la región tratada. La localización más frecuente es el recto y la indicación más común de radioterapia corresponde a neoplasias de la región pélvica incluidos el recto, la próstata y el cérvix. Se estima que hasta la mitad de los pacientes que reciben radiación pélvica llega a desarrollar síntomas gastrointestinales asociados. Se presentan dos pacientes con metástasis óseas sacroilíacas y pélvicas secundarias a adenocarcinoma de próstata que recibieron radiación en la región lumbosacra y pélvica, ambos pacientes presentaron episodios de deposiciones con sangre que iniciaron tempranamente posterior a la radioterapia. La colonoscopia mostró eritema y ulceración. En el estudio histopatológico se observó un patrón de colitis isquémica, con núcleo y citomegalia, estroma fibroso con cambios reactivos y abundante infiltrado inflamatorio neutrofílico. Estos hallazgos son característicos de la colitis actínica aguda; sin embargo, la localización cecal no ha sido frecuentemente reportada. Aunque al ser el ciego y el íleon terminal móviles de localización pélvica, se convierten en un factor de riesgo para que estos segmentos anatómicos sean susceptibles al impacto directo de la radioterapia. Esta condición, en la fase aguda, es autolimitada y se suele resolver con medidas de soporte. Es indispensable que el personal involucrado en el manejo de estos pacientes conozca esta entidad y los posibles diagnósticos diferenciales.

Abstract By definition, actinic colitis includes inflammatory changes of the colorectal mucosa secondary to radiation therapy of nearby tissue. The most frequent location is the rectum, and the most common indication for radiation therapy is a pelvic region neoplasm in the rectum, prostate or cervix. It is estimated that up to half of patients receiving pelvic radiation go on to develop associated gastrointestinal symptoms. We present two patients with sacroiliac and pelvic bone metastases secondary to prostate adenocarcinoma who received radiation in the lumbosacral and pelvic region. Both patients developed bloody stools soon after radiation therapy. Colonoscopy showed erythema and ulceration, and histopathology found a pattern of ischemic colitis with nucleus and cytomegalovirus infection, fibrous stroma with reactive changes and abundant inflammatory infiltration of neutrophils. These findings are characteristic of acute actinic colitis, but the cecal location has not been reported frequently. Nevertheless, the pelvic location of the cecum and the terminal ileum puts these anatomical segments at risk from the direct impact of radiation therapy. In the acute phase, this condition, is self-limiting and usually resolves with support measures. It is essential that the personnel involved in the management of these patients be aware of this entity and its possible differential diagnoses.

Merkel Cell Carcinoma and Diagnostic Experience in a Reference Hospital: A Case Series.

Merkel cell carcinoma (MCC) is a rare poorly differentiated neuroendocrine tumor, usually located in sun-exposed skin, with aggressive behavior and with high recurrence risk and metastatic disease. In Latin America, case series have been published, and it does not exceed 32 patients in 10 years, and in Colombia, there are case reports. We present a descriptive retrospective cross-sectional study in patients diagnosed with MCC in the Department of Pathology and Laboratories at the University Hospital Fundación Santa Fe de Bogotá(FSFB) between January 2003 and December 2018. We present the demographic, clinical, and pathological variables of these patients, as well as a literature review.

Epithelioid hemangioendothelioma of the parotid gland: a case report in an unusual location with a review of the literature / Hemangioendotelioma epitelioide de la glándula parótida: reporte de un caso de una localización inusual y revisión de la literatura

Epithelioid hemangioendothelioma (EHE) is a malignant vascular tumor that usually affects the liver, lung, bone and deep soft tissues of the extremities or trunk. To our knowledge, only 3 cases in the parotid gland have been reported to date. We report a case of a 62-year-old woman who presented with a 1-year history of a slow-growing, painless mass over the left mandibular angle. Imaging studies showed a 2cm mass over the left parotid gland with peripheral calcifications. The patient underwent a superficial parotidectomy. Sections displayed neoplastic epithelioid cells with cytoplasmic vacuoles containing erythrocytes, surrounded by a myxohyaline stroma. Immunohistochemistry was positive for CD31, CD34, ERG, and factor VIII, but negative for cytokeratin AE1/AE3, CK7, EMA, SMA, and S100. The findings were those of an EHE involving the parotid gland. This case demonstrates an EHE in a rare location and emphasizes the need to consider this tumor when diagnosing uncommon soft tissue tumors of salivary glands

El hemangioendotelioma epitelioide (HEE) es un tumor vascular maligno, que generalmente afecta el hígado, los pulmones, los huesos y los tejidos blandos profundos de las extremidades o el tronco. Por lo que sabemos, solo 3 casos reportados en la literatura han descrito este tumor en la glándula parótida. Presentamos el caso de una mujer de 62 años que presentó una historia de un año, de una masa indolora, de crecimiento lento sobre el ángulo mandibular izquierdo. Los estudios de imagen mostraron una masa de 2cm sobre la glándula parótida izquierda con calcificaciones periféricas. La paciente se sometió a una parotidectomía superficial. Los cortes mostraron células epitelioides neoplásicas con vacuolas citoplasmáticas que contenían eritrocitos, rodeadas por un estroma mixohialino. Se demostró mediante técnicas de inmunohistoquímica positividad en la celularidad neoplásica para CD31, CD34, ERG y factor VIII, pero negatividad para la citoqueratina AE1/AE3, CK7, EMA, SMA y S100. Estos hallazgos fueron los de un HEE comprometiendo la glándula parótida. Este caso demuestra un HEE en una localización rara y enfatiza la necesidad de considerar este tumor al diagnosticar tumores raros de tejidos blandos de glándulas salivales

Epithelioid hemangioendothelioma of the parotid gland: A case report in an unusual location with a review of the literature.

Epithelioid hemangioendothelioma (EHE) is a malignant vascular tumor that usually affects the liver, lung, bone and deep soft tissues of the extremities or trunk. To our knowledge, only 3 cases in the parotid gland have been reported to date. We report a case of a 62-year-old woman who presented with a 1-year history of a slow-growing, painless mass over the left mandibular angle. Imaging studies showed a 2cm mass over the left parotid gland with peripheral calcifications. The patient underwent a superficial parotidectomy. Sections displayed neoplastic epithelioid cells with cytoplasmic vacuoles containing erythrocytes, surrounded by a myxohyaline stroma. Immunohistochemistry was positive for CD31, CD34, ERG, and factor VIII, but negative for cytokeratin AE1/AE3, CK7, EMA, SMA, and S100. The findings were those of an EHE involving the parotid gland. This case demonstrates an EHE in a rare location and emphasizes the need to consider this tumor when diagnosing uncommon soft tissue tumors of salivary glands.

Esophageal tuberculosis in an HIV-positive patient mimicking a spindle cell tumor / Tuberculosis esofágica en un paciente VIH-positivo simulando un tumor de células fusiformes

Tuberculosis (TB) of the esophagus is an extremely rare condition, even in immunocompromised PATIENTS: We report the case of a 24-year-old man with a past history of HIV and pulmonary tuberculosis who presented with dysphagia and a 2cm submucosal mass in the proximal esophagus. The biopsy was diagnosed as a spindle cell neoplasm in another center. Sections displayed a submucosal lesion formed by spindle and epithelioid cells, surrounded by chronic inflammation. The spindle cells were positive for S100 and CD68, but negative for cytokeratin, desmin, smooth muscle actin, ALK, CD34 and CD117. Ziehl-Neelsen stain was performed and showed many intracellular acid-fast bacilli, confirming the diagnosis of esophageal TB. This case is a reminder that esophageal TB may become manifest as a submucosal lesion and the histiocytic-granulomatous reaction may mimic a spindle cell tumor

La tuberculosis (TB) del esófago es una condición extremadamente rara incluso en pacientes inmunocomprometidos. Presentamos el caso de un varón de 24 años con historia médica de VIH y TB pulmonar, que consultó por disfagia y una masa submucosa de 2cm en el esófago proximal. La biopsia fue derivada de una institución externa como una neoplasia de células fusiformes. Los cortes mostraron una lesión submucosa formada por células fusiformes y epitelioides, rodeadas de inflamación crónica. Las células fusiformes fueron positivas para S100 y CD68, pero negativas para citoqueratina, desmina, actina de músculo liso, ALK, CD34 y CD117. Se realizó la tinción de Ziehl-Neelsen y mostró muchos bacilos intracelulares ácido-alcohol resistente, confirmando el diagnóstico de TB esofágica. Este caso es un recordatorio de que la TB esofágica puede manifestarse como una lesión submucosa y la reacción histiocítica-granulomatosa puede simular un tumor de células fusiformes

Esophageal tuberculosis in an HIV-positive patient mimicking a spindle cell tumor.

Tuberculosis (TB) of the esophagus is an extremely rare condition, even in immunocompromised patients. We report the case of a 24-year-old man with a past history of HIV and pulmonary tuberculosis who presented with dysphagia and a 2cm submucosal mass in the proximal esophagus. The biopsy was diagnosed as a spindle cell neoplasm in another center. Sections displayed a submucosal lesion formed by spindle and epithelioid cells, surrounded by chronic inflammation. The spindle cells were positive for S100 and CD68, but negative for cytokeratin, desmin, smooth muscle actin, ALK, CD34 and CD117. Ziehl-Neelsen stain was performed and showed many intracellular acid-fast bacilli, confirming the diagnosis of esophageal TB. This case is a reminder that esophageal TB may become manifest as a submucosal lesion and the histiocytic-granulomatous reaction may mimic a spindle cell tumor.

CT Detectability of Small Low-Contrast Hypoattenuating Focal Lesions: Iterative Reconstructions versus Filtered Back Projection.

Purpose To investigate performance in detectability of small (≤1 cm) low-contrast hypoattenuating focal lesions by using filtered back projection (FBP) and iterative reconstruction (IR) algorithms from two major CT vendors across a range of 11 radiation exposures. Materials and Methods A low-contrast detectability phantom consisting of 21 low-contrast hypoattenuating focal objects (seven sizes between 2.4 and 10.0 mm, three contrast levels) embedded into a liver-equivalent background was scanned at 11 radiation exposures (volume CT dose index range, 0.5-18.0 mGy; size-specific dose estimate [SSDE] range, 0.8-30.6 mGy) with four high-end CT platforms. Data sets were reconstructed by using FBP and varied strengths of image-based, model-based, and hybrid IRs. Sixteen observers evaluated all data sets for lesion detectability by using a two-alternative-forced-choice (2AFC) paradigm. Diagnostic performances were evaluated by calculating area under the receiver operating characteristic curve (AUC) and by performing noninferiority analyses. Results At benchmark exposure, FBP yielded a mean AUC of 0.79 ± 0.09 (standard deviation) across all platforms which, on average, was approximately 2% lower than that observed with the different IR algorithms, which showed an average AUC of 0.81 ± 0.09 (P = .12). Radiation decreases of 30%, 50%, and 80% resulted in similar declines of observer detectability with FBP (mean AUC decrease, -0.02 ± 0.05, -0.03 ± 0.05, and -0.05 ± 0.05, respectively) and all IR methods investigated (mean AUC decrease, -0.00 ± 0.05, -0.04 ± 0.05, and -0.04 ± 0.05, respectively). For each radiation level and CT platform, variance in performance across observers was greater than that across reconstruction algorithms (P = .03). Conclusion Iterative reconstruction algorithms have limited radiation optimization potential in detectability of small low-contrast hypoattenuating focal lesions. This task may be further complicated by a high degree of variation in radiologists' performances, seemingly exceeding real performance differences among reconstruction algorithms. © RSNA, 2018 Online supplemental material is available for this article.

Malignant Solitary Fibrous Tumor of the Humerus: A Case Report of an Extremely Rare Primary Bone Tumor.

Solitary fibrous tumor (SFT) is a spindle-shaped cell neoplasm originally described in the pleura, but subsequently found in many anatomic sites. Only few cases of primary SFTs in the bone have been previously described in the literature. We present the case of an 86-year-old man with a 1-week history of pain in his left arm. Imaging studies demonstrated a well-defined osteolytic lesion in the proximal humerus measuring 6.1 cm in diameter. Sections showed a round to spindle-shaped cell neoplasm with prominent mitotic activity (28 mitoses per 10 high-power fields) and areas of necrosis, focally surrounding staghorn-shaped vessels. The tumor cells were positive for CD34, CD99, Bcl-2, and STAT6 and negative for smooth muscle actin, epithelial membrane antigen, and cytokeratin AE1/AE3. These findings were consistent with a malignant SFT involving the left humerus. Although extremely rare, SFT should be considered in the differential diagnosis of primary bone tumors. This is the first case report of a primary SFT in a long bone with malignant histological features.