SEOR SBRT-SG survey on SRS/SBRT dose prescription criteria in Spain

Aim Stereotactic body radiotherapy (SBRT) and stereotactic radiosurgery (SRS) are essential tools in radiation oncology. In Spain, the use of these techniques continues to grow as older linear accelerators (linacs) are replaced with modern equipment. However, little is known about inter-centre variability in prescription and dose heterogeneity limits. Consequently, the SBRT-Spanish Task Group (SBRT-SG) of the Spanish Society of Radiation Oncology (SEOR) has undertaken an initiative to assess prescription and homogeneity in SRS/SBRT treatment. In the present study, we surveyed radiation oncology (RO) departments to obtain a realistic overview of prescription methods used for SBRT and SRS treatment in Spain. Methods A brief survey was developed and sent to 34 RO departments in Spain, mostly those who are members of the SEOR SBRT-SG. The survey contained seven questions about the specific prescription mode, dose distribution heterogeneity limits, prescription strategies according to SRS/SBRT type, and the use of IMRT–VMAT (Intensity Modulated Radiation Therapy–Volumetric Modulated Arc Therapy). Results Responses were received from 29 centres. Most centres (59%) used the prescription criteria D95% ≥ 100%. Accepted dose heterogeneity was wide, ranging from 107 to 200%. Most centres used IMRT–VMAT (93%). Conclusions This survey about SRS/SBRT prescription and dose heterogeneity has evidenced substantial inter-centre variability in prescription criteria, particularly for intended and accepted dose heterogeneity. These differences could potentially influence the mean planning target volume dose and its correlation with treatment outcomes. The findings presented here will be used by the SEOR SBRT-SG to develop recommendations for SRS/SBRT dose prescription and heterogeneity (AU)

Recommended procedures and responsibilities for radiosurgery (SRS) and extracranial stereotactic body radiotherapy (SBRT): report of the SEOR in collaboration with the SEFM

Today, patient management generally requires a multidisciplinary approach. However, due to the growing knowledge base and increasing complexity of Medicine, clinical practice has become even more specialised. Radiation oncology is not immune to this trend towards subspecialisation, which is particularly evident in ablative radiotherapy techniques that require high dose fractions, such as stereotactic radiosurgery (SRS), and stereotactic body radiotherapy (SBRT). The aim of the present report is to establish the position of the Spanish Society of Radiation Oncology (SEOR), in collaboration with the Spanish Society of Medical Physics (SEFM), with regard to the roles and responsibilities of healthcare professionals involved in performing SRS and SBRT. The need for this white paper is motivated due to the recent changes in Spanish Legislation (Royal Decree [RD] 601/2019, October 18, 2019) governing the use and optimization of radiotherapy and radiological protection for medical exposure to ionizing radiation (article 11, points 4 and 5) [1 ], which states: “In radiotherapy treatment units, the specialist in Radiation Oncology will be responsible for determining the correct treatment indication, selecting target volumes, determining the clinical radiation parameters for each volume, directing and supervising treatment, preparing the final clinical report, reporting treatment outcomes, and monitoring the patient’s clinical course.” Consequently, the SEOR and SEFM have jointly prepared the present document to establish the roles and responsibilities for the specialists—radiation oncologists (RO), medical physicists (MP), and related staff —involved in treatments with ionizing radiation. We believe that it is important to clearly establish the responsibilities of each professional group and to clearly establish the professional competencies at each stage of the radiotherapy process (AU)

SEOR SBRT-SG survey on SRS/SBRT dose prescription criteria in Spain.

AIM: Stereotactic body radiotherapy (SBRT) and stereotactic radiosurgery (SRS) are essential tools in radiation oncology. In Spain, the use of these techniques continues to grow as older linear accelerators (linacs) are replaced with modern equipment. However, little is known about inter-centre variability in prescription and dose heterogeneity limits. Consequently, the SBRT-Spanish Task Group (SBRT-SG) of the Spanish Society of Radiation Oncology (SEOR) has undertaken an initiative to assess prescription and homogeneity in SRS/SBRT treatment. In the present study, we surveyed radiation oncology (RO) departments to obtain a realistic overview of prescription methods used for SBRT and SRS treatment in Spain. METHODS: A brief survey was developed and sent to 34 RO departments in Spain, mostly those who are members of the SEOR SBRT-SG. The survey contained seven questions about the specific prescription mode, dose distribution heterogeneity limits, prescription strategies according to SRS/SBRT type, and the use of IMRT-VMAT (Intensity Modulated Radiation Therapy-Volumetric Modulated Arc Therapy). RESULTS: Responses were received from 29 centres. Most centres (59%) used the prescription criteria D95% ≥ 100%. Accepted dose heterogeneity was wide, ranging from 107 to 200%. Most centres used IMRT-VMAT (93%). CONCLUSIONS: This survey about SRS/SBRT prescription and dose heterogeneity has evidenced substantial inter-centre variability in prescription criteria, particularly for intended and accepted dose heterogeneity. These differences could potentially influence the mean planning target volume dose and its correlation with treatment outcomes. The findings presented here will be used by the SEOR SBRT-SG to develop recommendations for SRS/SBRT dose prescription and heterogeneity.

Recommended procedures and responsibilities for radiosurgery (SRS) and extracranial stereotactic body radiotherapy (SBRT): report of the SEOR in collaboration with the SEFM.

Today, patient management generally requires a multidisciplinary approach. However, due to the growing knowledge base and increasing complexity of Medicine, clinical practice has become even more specialised. Radiation oncology is not immune to this trend towards subspecialisation, which is particularly evident in ablative radiotherapy techniques that require high dose fractions, such as stereotactic radiosurgery (SRS), and stereotactic body radiotherapy (SBRT). The aim of the present report is to establish the position of the Spanish Society of Radiation Oncology (SEOR), in collaboration with the Spanish Society of Medical Physics (SEFM), with regard to the roles and responsibilities of healthcare professionals involved in performing SRS and SBRT. The need for this white paper is motivated due to the recent changes in Spanish Legislation (Royal Decree [RD] 601/2019, October 18, 2019) governing the use and optimization of radiotherapy and radiological protection for medical exposure to ionizing radiation (article 11, points 4 and 5) [1 ], which states: "In radiotherapy treatment units, the specialist in Radiation Oncology will be responsible for determining the correct treatment indication, selecting target volumes, determining the clinical radiation parameters for each volume, directing and supervising treatment, preparing the final clinical report, reporting treatment outcomes, and monitoring the patient's clinical course." Consequently, the SEOR and SEFM have jointly prepared the present document to establish the roles and responsibilities for the specialists-radiation oncologists (RO), medical physicists (MP), and related staff -involved in treatments with ionizing radiation. We believe that it is important to clearly establish the responsibilities of each professional group and to clearly establish the professional competencies at each stage of the radiotherapy process.

100% peer review in radiation oncology: is it feasible?

PURPOSE: Peer review has been proposed as a strategy to ensure patient safety and plan quality in radiation oncology. Despite its potential benefits, barriers commonly exist to its optimal implementation in daily clinical routine. Our purpose is to analyze peer-review process at our institution. METHODS AND MATERIALS: Based on our group peer-review process, we quantified the rate of plan changes, time and resources needed for this process. Prospectively, data on cases presented at our institutional peer-review conference attended by physicians, resident physicians and physicists were collected. Items such as time to present per case, type of patient (adult or pediatric), treatment intent, dose, aimed technique, disease location and receipt of previous radiation were gathered. Cases were then analyzed to determine the rate of major change, minor change and plan rejection after presentation as well as the median time per session. RESULTS: Over a period of 4 weeks, 148 cases were reviewed. Median of attendants was six physicians, three in-training-physicians and one physicist. Median time per session was 38 (4-72) minutes. 59.5% of cases presented in 1-4 min, 32.4% in 5-9 min and 8.1% in ≥ 10 min. 79.1% of cases were accepted without changes, 11.5% with minor changes, 6% with major changes and 3.4% were rejected with indication of new presentation. Most frequent reason of change was contouring corrections (53.8%) followed by dose or fractionation (26.9%). CONCLUSION: Everyday group consensus peer review is an efficient manner to recollect clinical and technical data of cases presented to ensure quality radiation care before initiation of treatment as well as ensuring department quality in a feedback team environment. This model is feasible within the normal operation of every radiation oncology Department.

Validation of distal radius failure load predictions by homogenized- and micro-finite element analyses based on second-generation high-resolution peripheral quantitative CT images.

This study developed a well-standardized and reproducible approach for micro-finite element (mFE) and homogenized-FE (hFE) analyses that can accurately predict the distal radius failure load using either mFE or hFE models when using the approaches and parameters developed in this study. INTRODUCTION: Micro-FE analyses based on high-resolution peripheral quantitative CT (HR-pQCT) images are frequently used to predict distal radius failure load. With the introduction of a second-generation HR-pQCT device, however, the default modelling approach no longer provides accurate results. The aim of this study was to develop a well-standardized and reproducible approach for mFE and hFE analyses that can provide precise and accurate results for distal radius failure load predictions based on second-generation HR-pQCT images. METHODS: Second-generation HR-pQCT was used to scan the distal 20-mm section of 22 cadaver radii. The sections were excised and mechanically tested afterwards. For these sections, mFE and hFE models were made that were used to identify required material parameters by comparing predicted and measured results. Using these parameters, the models were cropped to represent the 10-mm region recommended for clinical studies to test their performance for failure load prediction. RESULTS: After identification of material parameters, the measured failure load of the 20-mm segments was in good agreement with the results of mFE models (R2 = 0.969, slope = 1.035) and hFE models (R2 = 0.966, slope = 0.890). When the models were restricted to the clinical region, mFE still accurately predicted the measured failure load (R2 = 0.955, slope = 1.021), while hFE predictions were precise but tended to overpredict the failure load (R2 = 0.952, slope = 0.780). CONCLUSIONS: It was concluded that it is possible to accurately predict the distal radius failure load using either mFE or hFE models when using the approaches and parameters developed in this study.

Whole-body diffusion-weighted magnetic resonance imaging (WB-DW-MRI) vs choline-positron emission tomography-computed tomography (choline-PET/CT) for selecting treatments in recurrent prostate cancer.

OBJECTIVE: To determine the effectiveness of whole-body diffusion-weighted magnetic resonance imaging (WB-DW-MRI) in detecting metastases by comparing the results with those from choline-positron emission tomography-computed tomography (choline-PET/CT) in patients with biochemical relapse after primary treatment, and no metastases in bone scintigraphy, CT and/or pelvic MRI, or metastatic/oligometastatic prostate cancer (PCa). Patients with this disease profile who could benefit from treatment with stereotactic body radiation therapy (SBRT) were selected and their responses to these techniques were rated. MATERIALS AND METHODS: This was a prospective, controlled, unicentric study, involving 46 consecutive patients from our centre who presented biochemical relapse after adjuvant, salvage or radical treatment with external beam radiotherapy, or brachytherapy. After initial tests (bone scintigraphy, CT, pelvic MRI), 35 patients with oligometastases or without them were selected. 11 patients with multiple metastases were excluded from the study. WB-DW-MRI and choline-PET/CT was then performed on each patient within 1 week. The results were interpreted by specialists in nuclear medicine and MRI. If they were candidates for treatment with ablative SBRT (SABR), they were then evaluated every three months with both tests. RESULTS: Choline-PET/CT detected lesions in 16 patients that were not observable using WB-DW-MRI. The results were consistent in seven patients and in three cases, a lesion was observed using WB-DW-MRI that was not detected with choline-PET/CT. The Kappa value obtained was 0.133 (p = 0.089); the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of WB-DW-MRI were estimated at 44.93, 64.29, 86.11, and 19.15%, respectively. For choline-PET/CT patients, the sensitivity, specificity, PPV, and NPV were 97.10, 58.33, 93.06, and 77.78%, respectively. CONCLUSIONS: Choline-PET/CT has a high global sensitivity while WB-DW-MRI has a high specificity, and so they are complementary techniques. Future studies with more enrolled patients and a longer follow-up period will be required to confirm these data. The initial data show that the best technique for evaluating response after SBRT is choline-PET/CT. Trial registration number NCT02858128.

Spanish Society of Radiation Oncology clinical guidelines for stereotactic body radiation therapy in lymph node oligometastases.

Data in the literature support the existence of a state of limited metastases or oligometastases. Favorable outcomes have been observed in selected patients with such oligometastases that are treated with local ablative therapies, which include surgical extirpation, stereotactic body radiation therapy (SBRT), and radiofrequency ablation. The role of SBRT in the setting of lymph node oligometastases is still emerging but the early results for local control are promising. However, the biggest challenge is to identify patients who will benefit from treatment of their oligometastatic disease with local aggressive therapy. Patients are initially categorized based upon examination of the initial biopsy, location, stage, and previous treatments received. Appropriate patient management with SBRT requires an understanding of several clinicopathological features that help to identify several subsets of patients with more responsive tumors and a good tolerance to SBRT. In an effort to incorporate the most recent evidence, here the Spanish Society of Radiation Oncology presents guidelines for using SBRT in lymph node oligometastases.

Dibenzofuran-induced mitochondrial dysfunction: Interaction with ANT carrier.

Exposure to environmental pollutants such as dibenzofurans and furans is linked to the pathophysiology of several diseases. Dibenzofuran (DBF) is listed as a pollutant of concern due to its persistence in the environment, bioaccumulation and toxicity to humans, being associated with the development of lung diseases and cancers, due to its extremely toxic properties such as carcinogenic and teratogenic. Mitochondria play a key role in cellular homeostasis and keeping a proper energy supply for eukaryotic cells is essential in the fulfillment of the tissues energy-demand. Therefore, interference with mitochondrial function leads to cell death and organ failure. In this work, the effects of DBF on isolated rat liver mitochondria were analyzed. DBF exposure caused a markedly increase in the lag phase that follows depolarization induced by ADP, indicating an effect in the phosphorylative system. This was associated with a dose-dependent decrease in ATPase activity. Moreover, DBF also increased the threshold to the induction of the mitochondrial permeability transition (MPT) by calcium. Pretreatment of mitochondria with DBF also increased the concentration of carboxyatractyloside (CAT) necessary to abolish ADP phosphorylation and to induce the MPT, suggesting that DBF may interfere with mitochondria through an effect on the adenine nucleotide translocase (ANT). By co-immunoprecipitating ANT and Cyclophilin D (CypD) following MPT induction, we observed that in the presence of DBF, the ratio CypD/ANT was decreased. This demonstrates that DBF interferes with the ANT and so prevents CypD binding to the ANT, causing decreased phosphorylative capacity and inhibiting the MPT, which is also reflected by an increase in calcium retention capacity. Clarifying the role of pollutants in some mechanisms of toxicity, such as unbalance of bioenergetics status and mitochondrial function, may help to explain the progressive and chronic evolution of diseases derived from exposure to environmental pollutants.

Pseudoobstrucción intestinal en la distrofia miotónica de Steinert: descripción clínico-radiológica de dos casos / Intestinal pseudo-obstruction in Steinert myotonic dystrophy: a clinical-radiological description of 2 cases

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The contribution of the cone beam Kv (CBKvCT) to the reduction in toxicity of prostate cancer treatment with external 3D radiotherapy

OBJECTIVE: Show that verification through cone beam Kv CT (CBKvCT) in a series of patients treated with 3D external radiotherapy (3DRT) for prostate cancer (PC) is related to a reduction in acute and late toxicity levels. MATERIALS AND METHOD: A retrospective, non-randomized study of two homogeneous groups of patients treated between 2005 and 2008, 46 were verified using electronic portal devices (EPIDs) and 48 through CBKvCT. They received 3DRT for localized PC (T1-T3N0M0) and were prescribed the same doses. Treatment was simulated and planned with the same criteria with the same equipment with a median follow-up time of 24 months (12-54 months). Urinary and gastrointestinal toxicity was determined using Common Toxicity Criteria scale, version 4 and RTOG scales. Statistical analysis of data was performed where p < 0.005 being significative. RESULTS AND DISCUSSION: With an overall median follow-up time of 24 months, the levels of proctitis were, respectively, 19.56, 15.21 and 15.2 % in the first group, compared with 4.17, 2.08 and 8.33 % in the second. Statistically, less total and late proctitis, late rectal bleeding, anal fissure, total and acute haematuria, total and acute urinary frequency and total urinary incontinence was observed. No statistically significant evidence of a lowering in toxicity neither in terms of acute and late dysuria nor of a relationship to the TNM, Gleason or PSA or in the grade of stability. CONCLUSION: Verification through CBKvCT in this series is associated with a statistically significant lowering toxicity. This justifies its use. Greater monitoring would be necessary to assess the impact of verification at the level of biochemical control (AU)

Uso de ecopotenciador en lesión renal quística compleja / The use of ultrasound with potentiator media in the diagnosis of complex cystic lesions

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Temperature-dependent Raman study of thermal parameters in CdS quantum dots.

We report on the strong temperature-dependent thermal expansion, α(D), in CdS quantum dots (QDs) embedded in a glass template. We have performed a systematic study by using the temperature-dependent first-order Raman spectra, in CdS bulk and in dot samples, in order to assess the size dependence of α(D), and where the role of the compressive strain provoked by the glass host matrix on the dot response is discussed. We report the Grüneisen mode parameters and the anharmonic coupling constants for small CdS dots with mean radius R âˆ¼ 2.0 nm. We found that γ parameters change, with respect to the bulk CdS, in a range between 20 and 50%, while the anharmonicity contribution from two-phonon decay channel becomes the most important process to the temperature-shift properties.

Ultrasound diagnosis of three cases of Mondor's disease.

OBJECTIVE: To describe clinical features and ultrasound findings of three cases of a little-known and relatively infrequent entity in daily clinical activity, which is often unnoticed and under-reported: penile Mondor's disease or superficial penile veins thrombophlebitis. METHODS: We are reporting the cases of three patients aged 33, 25 and 39 years who were referred to our department, the first case with suspicion of inguinal hernia, the second one to rule out testicular pathology because of pubic and perineal discomfort, and the third one for painful induration of the dorsal region of the penis. The three patients underwent Doppler-ultrasound examination (Toshiba®, using a 13-18MHz linear transducer) to establish definitive diagnosis, and had a favorable evolution with conservative management. RESULTS: Ultrasound examination revealed: Case 1. Penile superficial dorsal vein and lateral superficial veins thrombosis. Case 2. Thrombosis of the right branch of the superficial dorsal vein and its perineal distal connections. Case 3. Penile superficial dorsal vein thrombosis. Definitive diagnosis of the three cases was Mondor's disease. CONCLUSIONS: Mondor's disease is an often under-reported entity in daily clinical activity. Doppler-ultrasound findings (echogenic material within veins, lack of any response after compression by the transducer and absence of color flow) confirm de diagnosis. This disease has a favorable evolution and functional prognosis. Knowledge of Mondor's disease by echographists is basic to avoid false-negative results in radiologic examination.

Diagnóstico ecográfico de tres caso de enfermedad de Mondor del pene / Ultrasound diagnosis of three cases of Mondor`s disease

OBJETIVO: Describir las características clínicas y los hallazgos ecográficos de tres casos de una entidad poco conocida y relativamente infrecuente en la actividad clínica diaria, lo que ocasiona que sea infradiagnosticada: la enfermedad de Mondor del pene o tromboflebitis aislada de las venas superficiales del pene. MÉTODOS: Los casos corresponden a pacientes de 33, 25 y 39 años remitidos el primero por sospecha de hernia inguinal, el segundo para descartar patología testicular por molestias púbicas y perineales, y el tercero por induración dolorosa del dorso del pene. Se realizó ecografía-Doppler color de alta resolución (Toshiba®, con transductor lineal de 13-18 MHz) y tras el diagnóstico se instauró tratamiento conservador, evolucionando los tres casos de forma favorable. RESULTADOS: En el estudio ecográfico se apreció: Caso 1. Trombosis de la vena dorsal superficial y venas laterales superficiales. Caso 2. Trombosis de la rama derecha de la vena dorsal superficial y de sus conexiones distales perineales. Caso 3. Trombosis de la vena superficial dorsal del pene. Los tres casos fueron diagnosticados como enfermedad de Mondor. CONCLUSIONES: La enfermedad de Mondor es una entidad frecuentemente infradiagnosticada en la práctica diaria. Los hallazgos ecográficos-Doppler (contenido ecogénico en el interior de la vena, falta de respuesta a la compresión y ausencia de flujo) son diagnósticos. Se trata de una entidad clínica con buena evolución y pronóstico funcional. Es fundamental el conocimiento de esta entidad por parte del ecografista para evitar falsos negativos en el estudio radiológico(AU)

OBJECTIVE: To describe clinical features and ultrasound findings of three cases of a little-known and relatively infrequent entity in daily clinical activity, which is often unnoticed and under-reported: penile Mondor’s disease or superficial penile veins thrombophlebitis. METHODS: We are reporting the cases of three patients aged 33, 25 and 39 years who were referred to our department, the first case with suspicion of inguinal hernia, the second one to rule out testicular pathology because of pubic and perineal discomfort, and the third one for painful induration of the dorsal region of the penis. The three patients underwent Doppler-ultrasound examination (Toshiba®, using a 13-18MHz linear transducer) to establish definitive diagnosis, and had a favorable evolution with conservative management. RESULTS: Ultrasound examination revealed: Case 1. Penile superficial dorsal vein and lateral superficial veins thrombosis. Case 2. Thrombosis of the right branch of the superficial dorsal vein and its perineal distal connections. Case 3. Penile superficial dorsal vein thrombosis. Definitive diagnosis of the three cases was Mondor’s disease. CONCLUSIONS: Mondor’s disease is an often under-reported entity in daily clinical activity. Doppler-ultrasound findings (echogenic material within veins, lack of any response after compression by the transducer and absence of color flow) confirm de diagnosis. This disease has a favorable evolution and functional prognosis. Knowledge of Mondor’s disease by echographists is basic to avoid false-negative results in radiologic examination(AU)

Retroperitoneal cystic mature teratoma as the presenting clinical scenario of testicular carcinoma.

OBJECTIVE: To describe a case of retroperitoneal mature teratoma presenting as metastasis of a testicular mixed germ cell tumor in a thirty year old man who had lumbar and abdominal pain and mass sensation in the left hemiabdomen. METHODS: Abdominal ultrasound and thoracic-abdominal-pelvic CT multidetector scan were performed, and then after a Doppler ultrasound study of the testicles. Surgical treatment was performed: orchiectomy and retroperitoneal lesion resection. RESULTS: Imaging studies showed a big cystic lesion in the left retroperitoneal space, 13 × 12 × 11 cm, well defined, with thin septa, displacing the kidney; and a solid-cystic 4 cm left testicular tumor, with multiple septa, solid poles and arterial flows with low resistances. Thoracic extension study did not show any finding. The histopathologic results of the orchiectomy and retroperitoneal resection pieces were, respectively, testicular mixed germ cell tumor (seminoma, with intratubular seminoma foci and teratoma) and mature cystic teratoma. CONCLUSIONS: Germ cell tumors derive from multipotencial cells with a large capacity of differentiation, and the nodal paraaortic chains are a natural way of dissemination of these neoplasms. Because of that, in the presence of a retroperitoneal lesion in a young patient we have to rule out testicular tumor metastasis. The retroperitoneal mature cystic teratoma must be considered as a lesion with malignant potential.

Teratoma quístico maduro retroperitoneal como primera manifestación de carcinoma testicular. Estudio radiológico / Retroperitoneal cystic mature teratoma as the presenting clinical scenario of testicular carcinoma. Radiological study

OBJETIVO: Describir un caso de teratoma maduro retroperitoneal como metástasis de un tumor mixto de células germinales testicular en un paciente de 30 años que debutó con dolor lumbar, abdominal y sensación de masa en hemiabdomen izquierdo.MÉTODOS: Se realizó ecografía abdominal, TC multidetector tóraco-abdomino-pélvico, y ante los hallazgos apreciados ecografía-doppler testicular. Se practicó orquiectomía y resección de la lesión retroperitoneal. RESULTADOS: En las pruebas de imagen se apreció a nivel retroperitoneal izquierdo una gran lesión quística de 13x12x11 cm de diámetro, bien delimitada, con finos septos, que desplazaba el riñón; y una masa testicular de 4 cm, sólido-quística, multiseptada, con polos sólidos y flujos vasculares arteriales de baja resistencia. El estudio de extensión torácico no mostró hallazgos. Los resultados anatomopatológicos de las piezas de orquiectomía y de la lesión retroperitoneal fueron respectivamente: tumor mixto de células germinales (seminoma, con focos de seminoma intratubular y teratoma), y teratoma quístico maduro.CONCLUSIONES: Debido a que los tumores de células germinales derivan de células multipotenciales con gran capacidad de diferenciación y que las cadenas ganglionares paraaórticas constituyen una vía de diseminación natural de estas neoplasias, la presencia de una lesión retroperitoneal en un paciente joven, aún sin signos radiológicos de malignidad (en nuestro caso quística) obliga a descartar metástasis de tumor testicular. El teratoma maduro retroperitoneal postpuberal debe considerarse una lesión con potencial maligno(AU)

OBJECTIVE: To describe a case of retroperitoneal mature teratoma presenting as metastasis of a testicular mixed germ cell tumor in a thirty year old man who had lumbar and abdominal pain and mass sensation in the left hemiabdomen.METHODS: Abdominal ultrasound and thoracic-abdominal-pelvic CT multidetector scan were performed, and then after a Doppler ultrasound study of the testicles. Surgical treatment was performed: orchiectomy and retroperitoneal lesion resection.RESULTS: Imaging studies showed a big cystic lesion in the left retroperitoneal space, 13 x 12 x 11 cm, well defined, with thin septa, displacing the kidney; and a solid-cystic 4 cm left testicular tumor, with multiple septa, solid poles and arterial flows with low resistances. Thoracic extension study did not show any finding. The histopathologic results of the orchiectomy and retroperitoneal resection pieces were, respectively, testicular mixed germ cell tumor (seminoma, with intratubular seminoma foci and teratoma) and mature cystic teratoma.CONCLUSIONS: Germ cell tumors derive from multipotencial cells with a large capacity of differentiation, and the nodal paraaortic chains are a natural way of dissemination of these neoplasms. Because of that, in the presence of a retroperitoneal lesion in a young patient we have to rule out testicular tumor metastasis. The retroperitoneal mature cystic teratoma must be considered as a lesion with malignant potential(AU)