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The examination of morphological alterations in tissues is fundamental in Pathology. Traditional training in gross dissection has several limitations, including the risk of transmissible diseases, formaldehyde exposure and limited specimen availability. We describe a teaching method using anatomical simulators.Liquid silicone-based artisan neoplastic anatomical models were used in conjunction with clinical scenarios. Eighty-five medical students participated in a gross dissection experience and were asked to complete a feedback questionnaire. Additionally, a workshop was organized for students to compare three different teaching methods. The first one used still images (Group1-G1), the second a video explanation (Group2-G2), and the third directly observed a pathologist while grossing (Group3-G3).The knowledge acquisition questionnaire showed an average value of 4.4 out of 5 (1-5) (range 3.4-4.7, σ0.89). The categories 'knowledge of resection margins' and 'macroscopic diagnosis' received the highest values (4.8, σ0.11 and 4.7, σ0.32, respectively), followed by 'understanding of handling and gross examination of the surgical specimen' (4.5, σ0.49), 'prognosis' (4.3, σ0.67) and 'understanding of a tumor resection' (3.9, σ0.96) (p0.05). Regarding teaching methods, G3 spent less time than G2 and G1 with mean times of 15'39″ (σ2'12″), 16'50″ (σ3'45″), and 17'52″ (σ2'12″), respectively (p0.05). Gross dissection marks (0-5) showed statistically significant differences (p0.05). G2 obtained better results (3.7;σ0.54) than G3 (3.4;σ0.94) or G1 (3.1;σ0.8).This preliminary study demonstrates that it is possible to implement a gross dissection simulation module at medical school and thus enable the acquisition of skills in a secure environment.

BACKGROUND: To the authors' knowledge, the impact of the coronavirus disease 2019 (COVID-19) pandemic on cytopathology practices worldwide has not been investigated formally. In the current study, data from 41 respondents from 23 countries were reported. METHODS: Data regarding the activity of each cytopathology laboratory during 4 weeks of COVID-19 lockdown were collected and compared with those obtained during the corresponding period in 2019. The overall number and percentage of exfoliative and fine-needle aspiration cytology samples from each anatomic site were recorded. Differences in the malignancy and suspicious rates between the 2 periods were analyzed using a meta-analytical approach. RESULTS: Overall, the sample volume was lower compared with 2019 (104,319 samples vs 190,225 samples), with an average volume reduction of 45.3% (range, 0.1%-98.0%). The percentage of samples from the cervicovaginal tract, thyroid, and anorectal region was significantly reduced (P < .05). Conversely, the percentage of samples from the urinary tract, serous cavities, breast, lymph nodes, respiratory tract, salivary glands, central nervous system, gastrointestinal tract, pancreas, liver, and biliary tract increased (P < .05). An overall increase of 5.56% (95% CI, 3.77%-7.35%) in the malignancy rate in nongynecological samples during the COVID-19 pandemic was observed. When the suspicious category was included, the overall increase was 6.95% (95% CI, 4.63%-9.27%). CONCLUSIONS: The COVID-19 pandemic resulted in a drastic reduction in the total number of cytology specimens regardless of anatomic site or specimen type. The rate of malignancy increased, reflecting the prioritization of patients with cancer who were considered to be at high risk. Prospective monitoring of the effect of delays in access to health services during the lockdown period is warranted. ispartof: CANCER CYTOPATHOLOGY vol:128 issue:12 pages:885-894 ispartof: location:United States status: published

Background: In a previous worldwide survey, the authors showed a drastic reduction in the number of cytological specimens processed during the coronavirus disease 2019 “lockdown” period along with an increase in malignancy rates. To assess the continued impact of the pandemic on cytological practices around the world, they undertook a second follow-up worldwide survey collecting data from the post-lockdown period (2020). Methods: Participants were asked to provide data regarding their cytopathology activity during the first 12 weeks of their respective national post-lockdown period (2020), which ranged from April 4 to October 31. Differences between the post-lockdown period and the corresponding 2019 period were evaluated, and the authors specifically focused on rates of malignant diagnoses. Results: A total of 29 respondents from 17 countries worldwide joined the survey. Overall, a lower number of cytological specimens (n = 236,352) were processed in comparison with the same period in 2019 (n = 321,466) for a relative reduction of 26.5%. The overall malignancy rate showed a statistically significant increase (12,442 [5.26%] vs 12,882 [4.01%]; P

Echenique M et al (1) described a lymphangioma as a rare cystic neoplasm of the pancreas. We present a similar lesion in pancreas diagnosed by endoscopic ultrasound (EUS)-fine-needle aspiration (FNA) cytology. Abdominal-doppler-ultrasound in asymptomatic 52-year-old man showed two anechoic cystic masses near the pancreas without vascularization. Subsequent gadolinium-enhanced-magnetic-resonance-imaging (MRI) was performed and demonstrated two cystic T2-hyperintense lesions with mild septal enhancement after gadolinium contrast administration, but the origin of the lesion could not be identified. An EUS showed two cystic lesions with internal debris and septations: one of 48×29mm adjacent to tail of pancreas and other of 38x24mm between duodenum and liver (Fig1.a). Under EUS guidance, we obtained 40 ml translucent fluid from one of the cystic lesion using a 22 gauge EchoTip® needle (Cook Medical, Bloomington, Indiana, United States). Rapid on-site evaluation of the smears by a cytopathologist showed granular proteinaceous background with small mature lymphocytes (Fig1.b). Cytospin and immunostains confirmed uniform lymphocytic population with CD45 (Fig1.c) and assessed the polyclonal (T-CD3/B-CD20) nature of the lymphocytes, rendering the diagnosis of lymphangioma. Lymphangiomas are rare benign lymphatic lesions that may occur in any location. The abdominal localization is unusual (2). Although often asymptomatic, the clinical presentation is variable depending on the size and consequent mass effect or complications (2-4). In less than 10% of cases, the involvement is diffuse or multifocal, called lymphangiomatosis. Because the imaging appearance of pancreatic lymphangiomas overlaps with other cystic masses, the diagnosis may be difficult and can only be made with cyst aspiration and histopathologic examination. Histologically, dilated lymphatic spaces are lined with endothelial cells and are composed of collagenous connective tissue and smooth muscle. The supporting stroma may content lymphocytes (2, 5). Treatment often involves conservative surgical excision or percutaneous sclerosis in symptomatic patients, instead it is possible imaging surveillance in asymptomatic patients (4).

The high prevalence of musculoskeletal disorders in pathologists, together with the current trend towards the digitization of pathology, prompted us to study the different types of input devices employed during the revision of whole slide images, in order to investigate the pattern and extent of muscle activity involved in their use.A comparative study was made of 10 input devices (conventional and vertical mouse, three trackballs, the Ergopointer™, the Rollermouse™, an optical pen mouse, a touchpad, and the Leap Motion™). Six medical students performed a standardized circuit using a Fitts' Law based tissue array, digitized. The electrical activity of seven upper limb muscles (adductor pollicis, extensor pollicis longus, extensor digitorum, flexor digitorum, middle deltoid, upper trapezius, and middle trapezius) was measured using surface electromyography.Statistically significant differences in the overall electrical activity among the different input devices, both absolute values in mV as well as normalized values to the upper limb at rest, were observed (p0.001); the Rollermouse™ (0.1027mV; 139%), Logitech M570 trackball (0.1053mV; 145%), Ergopointer™ (0.1151mV; 167%), conventional mouse (0.1251mV; 191%), and vertical mouse (0.1312mV; 205%) required less activity, while the optical pen mouse (0.1717mV; 299%), Leap Motion™ (0.1803mV; 319%), Expert Mouse trackball (0.1845mV; 329%), EIGIIS trackball (0.2442mV; 468%) and the touchpad (0.2560mV; 496%) required greater muscle mobilization.We designed a system based on Fitts' Law to compare input devices in digital pathology. Variability between compared devices and muscle activity was found. Long-term use could result in different muscular fatigue patterns. Even though the selection of an input device is a matter of personal preference, its impact on ergonomics should be considered.

Background Inasmuch as the conventional mouse is not an ideal input device for digital pathology, the aim of this study was to evaluate alternative systems with the goal of identifying a natural user interface (NUI) for controlling whole slide images (WSI). Design Four pathologists evaluated three webcam-based, head-tracking mouse emulators: Enable Viacam (eViacam, CREA Software), Nouse (JLG Health Solutions Inc), and Camera Mouse (CM Solutions Inc). Twenty WSI dermatopathological cases were randomly selected and examined with Image Viewer (Ventana, AZ, USA). The NASA-TLX was used to rate the perceived workload of using these systems and time was recorded. In addition, a satisfaction survey was used. Results The mean total time needed for diagnosis with Camera Mouse, eViacam, and Nouse was 18’57“, 19’37” and 22’32“, respectively (57/59/68 seconds per case, respectively). The NASA-TLX workload score, where lower scores are better, was 42.1 for eViacam, 53.3 for Nouse and 60.62 for Camera Mouse. This correlated with the pathologists’ degree of satisfaction on a scale of 1-5: 3.4 for eViacam, 3 for Nouse, and 2 for Camera Mouse (p Conclusions Head-tracking systems enable pathologists to control the computer cursor and virtual slides without their hands using only a webcam as an input device. - Of the three software solutions examined, eViacam seems to be the best of those evaluated in this study, followed by Nouse and, finally, Camera Mouse. - Further studies integrating other systems should be performed in conjunction with software developments to identify the ideal device for digital pathology.

Background Twitter is an expanding social media network among cytopathologists to share knowledge. Tweets are made up of text which may also include images or video. All tweets labeled under a hashtag can be tracked. The #FNAFriday hashtag was created in 2015 by one of the authors (X.J.) to build a community of individuals, to educate and share interesting cases, and highlight a variety of diagnoses with FNA specimens. Methods We retrospectively extracted all tweets labeled with #FNAFriday from April 2015 to mid-February 2019 (47 mo) using the Twitter search engine. The data point included: author, number of figures, type of cytology-stain, use of immunocytochemistry, histochemistry or molecular techniques, and the subspeciality. The educational content was categorized as: live-tweeting, training activities, and publication references. The number if comments, retweets and likes was also recorded. Results A total of 349 original tweets using #FNAFriday were tracked with an average of 7.43 tweets/month. We describe the "top three" countries with most tweets, active users and subspecialties. The most frequent stain was Papanicolau and part of the content of the tweets was using cellblock (14.04%), histologic correlation (10.03%), immunocytochemistry (8.60%), molecular tests (2.01%), gross pictures (4.58%), and radiologic pictures (3.4%). Conclusion The presence of cytopathologists on Twitter who want to share their cases has increased. The weekly FNAFriday label with other cytology hashtags is a specific keyword for those interested in the field.

Resumen Introduccion La puncion aspiracion con aguja fina (PAAF) es un procedimiento diagnostico minimamente invasivo y extremadamente util para tipificar lesiones. La limitacion de medios en las practicas de anatomia patologica ha dificultado su ensenanza. Describimos la incorporacion de maniquies disenados para realizar PAAF en nuestro centro. Material y metodos Los maniquies consisten en 2 simuladores de tareas, artesanales y a tamano natural, de las regiones facial/cervical (modelo de utilidad U201500372) y de torso, respectivamente, revestidos por silicona, simulando piel, con areas tumorales. Permiten realizar PAAF (palpacion, puncion, aspiracion, obtencion de material y extension sobre portaobjetos) y son reutilizables. La practica se realizo durante 3 cursos academicos (2013-2016) y consistio en realizar PAAF de manera individualizada sobre contexto clinico, con ulterior correlacion citologica. Resultados Un total de 178 estudiantes de medicina de la Universidad de Murcia de tercer curso realizaron la practica (28 grupos: 105 mujeres, 73 hombres). La tasa de acierto (puncion, aspiracion de material y extension en portaobjetos) fue del 97,2% con la primera puncion. Ademas, 13 estudiantes procedentes de otras 10 universidades (nacionales e internacionales) llevaron a cabo la practica, refiriendo la no existencia en sus centros de procedencia. Fue considerada como de gran valor sobre encuesta anonima. Discusion Las practicas de PAAF son facilmente implementables y potencialmente incorporables a los formatos evaluativos tipo examen clinico objetivo estructurado (ECOE). No existe una adecuada estandarizacion en las practicas de diferentes centros universitarios. Las practicas de PAAF mejoran la formacion del estudiante y proporciona un mayor conocimiento y una mejor consideracion de nuestra especialidad.

Objectives Fine needle aspiration (FNA) is an invaluable diagnostic procedure for evaluation of lesions; however, acquisition of diagnostic material is dependent on the skill of the practitioner. We report a novel patient simulator for teaching the FNA procedure and structured assessment tools for educators and learners. Methods We created a novel simulator model for FNA training, employed a standardized teaching module, and assessed procedure utility in medical students. Groups of students completed training using a commercial version of the model, and underwent structured evaluation using an Objective Structured Assessment of Technical Skills (OSATS) form, and the Debriefing Assessment for Simulation in Healthcare (DASH) tool. Results In the initial phase, 178 students rated the training workshop between valuable and essential (4.2 on a 5-point Likert scale). In the second phase, for students evaluated with the OSATS form, the mean overall score was 33 out of 50 (range 26-43). The areas of weakness for the participants were: (a) compression after the FNA procedure, (b) completion of the informed consent, and (c) correct explanation of the procedure to the patient. For the group of students that completed the DASH questionnaire, the results were: 6.2 (assessment by students) and 6.7 (assessment by instructor) out of a maximum of 7. Conclusion A realistic simulation model, in combination with a standardized training program with formal assessment methods is a valuable tool to teach FNA. We here describe a process for teaching the FNA procedure to interested educators and learners.

Resumen Introduccion La Anatomia Patologica sigue siendo desconocida, no solo para el publico en general, sino tambien para nuestros companeros de profesion. El uso generalizado de las redes sociales permite difundir nuestra labor. Por ello, se planteo generar un grupo de trabajo. Material y metodos Se emitio una convocatoria a los socios de la Sociedad Espanola de Anatomia Patologica a traves de su Vocalia de Comunicacion y Proyeccion Social titulada #IWantYouForSEAP, para conformar una red de trabajo en la red social Twitter. El periodo de reclutamiento fue de un mes (agosto del 2016). Se registro la actividad desarrollada durante el XXVIII Congreso de la SEAP-IAP de 2017 utilizando las herramientas analiticas Symplur y Tweet Binder. Resultados Se recibieron 32 solicitudes (29 patologos, 2 tecnicos de Anatomia Patologica, un administrativo), con una distribucion geografica dentro del territorio espanol que incluyo a participantes de 14 de las 17 comunidades autonomas, perteneciendo a 22 ciudades y 25 centros distintos. La actividad en relacion con el hashtag #SEAP2017V utilizado en el congreso incluyo a 685 participantes, 6.704 tweets y 8.837.435 impresiones; 28 de los 32 reclutados por la campana #IWantYouForSEAP participaron, contribuyendo con 2.410 tweets y generando 2.090.423 impresiones (el 36 y el 24% del total, respectivamente). Conclusiones Es posible promover y motivar el trabajo en grupo dentro de nuestra disciplina a traves de las redes sociales. Se trata de una fase inicial, pero los resultados experimentados son alentadores y existen grandes expectativas por parte de los participantes. Un uso adecuado de las redes sociales podria acercar la figura del patologo a la sociedad.

Resumen Los patologos son medicos especializados en el diagnostico morfologico de las enfermedades a traves del estudio de muestras citotisulares para lo cual hacen uso, entre otras cosas, del microscopio optico. Dicho uso se ha visto relacionado con la aparicion de problemas musculo-esqueleticos. Se envio un cuestionario anonimo online a los miembros de la Sociedad Espanola de Anatomia Patologica con el fin de conocer la prevalencia de los mismos en los patologos que trabajan en Espana. Se incluyeron preguntas relacionadas con defectos visuales y sobre patologia digital. Completaron la encuesta un total de 557 patologos. Se describen y discuten los resultados.

Pathology is a speciality that is often poorly understood, not only by the general public, but also by clinicians. However, the recent widespread use of social media provides an opportunity to increase the visibility and comprehension of our profession. A working group was formed to carry out this task.The members of the Spanish Society of Pathology were contacted through its Communication and Social Projection Subcommittee to engage in the campaign #IWantYouForSEAP, to form a network on Twitter. The recruitment period was one month (August, 2016). The resulting project, developed during the XXVIII Congress of the SEAP-IAP, was registered using the analytical tools Symplur and Tweet Binder.32 applications (29 pathologists, 2 histotechnicians, 1 administrative personnel) were received from all over Spain, including participants from 14 of the 17 Autonomous Regions, from 22 cities and 25 medical centres. The activity in relation to the hashtag #SEAP2017V used in the congress included 685 participants with 6704 tweets and 8,837,435 impressions. 28 of the 32 recruited by the #IWantYouForSEAP campaign participated, contributing with 2410 tweets, and generating 2,090,423 impressions (36% and 24% of the total, respectively).It is possible to promote and motivate teamwork within our discipline through social media networks. This preliminary experience of the use of social media networks in our scientific community has had encouraging results which have raised high expectations among participants. An appropriate use of social media networks could help to narrow the gap between pathologists and society.

Resumen Los tumores benignos de la vaina del nervio periferico son relativamente frecuentes, siendo los principales representantes el neuroma solitario circunscrito, el neurofibroma y el schwannoma. Sin embargo, la variante epitelioide benigna del schwannoma de partes blandas es extremadamente rara y debe plantearse un cuidadoso diagnostico diferencial con otras entidades benignas y malignas. Se presenta el caso de un schwannoma epitelioide en un varon de 48 anos y se revisa la literatura asi como su diagnostico diferencial histologico e inmunohistoquimico.

Background Digital Pathology represents a technological innovation that introduces changes in the traditional tasks of pathologists. In this regard, an important issue that has not been enough emphasized is the image handling from an ergonomic point of view to avoid work-related musculoskeletal disorders (MSD). The aim of this study was to investigate a proper input device for digital pathology. Material & Methods Research was conducted in two phases: (1). A comparative study to find out an optimal external controller. Eight medical students analyzed 11 input devices: keyboard (Hewlett Packard, HP), conventional mouse (HP), vertical mouse (CLS), touchpad (Logitech), 3 trackballs (Logitech, Kensington Expert and Ulove), Rollermouse (Contour), Ergopointer (Märzhäuser Sensotech), gamepad (Logitech) and a touchless device (Leap Motion Controller), using them with the Image Viewer software (Ventana). The web-based Fitts´ law test (UC Berkeley) was used to objectify the accuracy of each used device, randomly. 12 items were included in the questionnaire: comfort, technical aspects (cursor movement and objective achievement), prospects, overall satisfaction, prior experience, and others. (2). Evaluation by two experienced pathologists of the best rated input device on the previous experiment and its comparison with a voice recognition system (Invox Medical Dictation, Vocali) using a headset microphone (Plantronics). Perceived workload was scored using the NASA Task Load Index on 28 whole slide images visualized on the Digital Image Hub (Leica) platform with a 4 MegaPixel display (Barco). Data were processed with SPSS 21.0. Results Correlation between technical aspects of the evaluated devices and accuracy (Fitts´ law test), and comfort with overall satisfaction, was demonstrated (p, Diagnostic Pathology, Vol 2 No 1 (2016): 2016

Background Scanning histological or cytological preparations is a crucial element in the process of digitization of Pathology Departments, along with the traceability of tissue samples and the reports management. The scanning time and the high size of the files are still considered suboptimal for full implementation. In order to optimize time and space a comparative study of the workflow performed by histotechnicians in our center has been carried out. Material & Methods A total of 25 endoscopic samples were selected with the intention of comparing different parameters (scanning time, error rate during scanning and hard disk storage) between the original histological glass slides (group A: 2 slides per case, 50 preparations) and new sections, with levels grouped into a single slide (group B: 1 slide per case, 25 preparations). They were scanned at 20x magnification in routine way using the Ventana iScan Coreo scanner (Roche diagnostics). The process was repeated 4 times to calculate averages. Results The average scanning time was 5 hours 40 minutes (6m 48s / slide) in group A and 5 hours 10 minutes (12m 24s / slide) in group B. The error rate was 6.1% in group A and 3,8% in group B. The space occupied on the hard disk was 11.87 GB in group A and 9.6 GB in group B (475 MB/case vs 385 MB/case, respectively). The average number of tissue sections per case was 7 in group A and 8 in group B. Conclusion There is a clear benefit of standardizing and optimizing the number of cuts per slide in terms of storage (saving 19%), biopsy sampling (14% more tissue) and error rate (37% less), including a not negligible decrease in the scanning time (9%) in the study conducted., Diagnostic Pathology, Vol 2 No 1 (2016): 2016

Introduction/ Background Digital Pathology represents a technological innovation that introduces changes in the traditional work of pathologists. In this regard, an important issue that has not been enough emphasized is the image handling from an ergonomic point of view to avoid work-related musculoskeletal disorders (MSD). Aims The aim of this study was to investigate a proper input device for digital pathology. Methods Research was conducted in two phases: 1. Comparative study to find an optimal external controller. Eight medical students analyzed 11 input devices: keyboard (HP), conventional mouse (HP), vertical mouse (CLS), touchpad (Logitech), 3 trackballs (Logitech, Kensington Expert and Ulove), Rollermouse (Contour), Ergopointer (Märzhäuser Sensotech), gamepad (Logitech) and a touchless device (Leap-Motion), using them with the Image Viewer software (Ventana). The web-based Fitts´ law test (UC Berkeley) was used to objectify the accuracy of each device, randomly. 12 items were included in the questionnaire: comfort, technical aspects (cursor movement and objective achievement), prospects, overall satisfaction, prior experience, and others. 2. Evaluation by two experienced pathologists (MPR and ANO, 55 and 50 year-old, respectively) the best rated input device and comparison with a voice recognition system (Invox Medical Dictation) using a headset microphone (Plantronics), rating perceived workload using NASA Task Load Index with 28 whole slide images. Digital Image Hub (Leica) with a 4 MegaPixel display (Barco) was used. Data were processed with SPSS 21.0. Results Correlation between technical aspects of the evaluated devices and accuracy (Fitts´ law test), and comfort with overall satisfaction existed (p, Diagnostic Pathology, Vol 1 No 8 (2016): 13. European Congress on Digital Pathology

Resumen La hiperplasia nodular oncocitica multifocal es una lesion infrecuente de la glandula parotida. Se presenta un caso de hiperplasia nodular oncocitica multifocal de la glandula parotida en espacio parafaringeo de una mujer de 74 anos y se revisan las lesiones oncociticas de la glandula parotida.

Ependymomas are the most frequent neoplasms of the spinal cord, arising from the cells lining the spinal canal. Among them, giant cell ependymoma is a rare subtype with only 8 cases previously reported to date. We present a further case in a 42-year-old man who presented with a history of lower back pain for several months. The MRI revealed a well-circumscribed interdural mass at L1. The tumour was totally resected and histologically it was seen to be comprised of a proliferation of fusiform cells arranged in a perivascular pattern with pseudorosettes and cytologic atypia with multinucleated giant cells. Immunohistochemistry confirmed the diagnosis of giant cell ependymoma.

Introduction Fine needle aspiration (FNA) guided by ecoendoscopy (EE) or endoscopic ultrasound (EUS) has become a useful diagnostic tool for cystic lesions of the pancreas. We present a case of mature cystic teratoma in the body of the pancreas which was diagnosed preoperatively and successfully treated with distal pancreatectomy and splenectomy. The characteristics, preoperative diagnosis and the differential diagnosis of this rare entity are discussed. Case History A 39 year old woman presented with epigastric pain. A computed tomography (CT) scan showed an 8.5 cm multicystic pancreatic mass. FNA guided by ecoendoscopy provided tissue for cytological examination which showed distinct types of epithelium (mucous, ciliary and squamous), leading to a preoperative diagnosis of mature cystic teratoma. Discussion Mature cystic teratoma of the pancreas is extremely rare and has a wide range of differential diagnoses which include cystic and pseudocystic tumours. FNA guided by ecoendoscopy is a useful tool for the preoperative diagnosis of pancreatic lesions but an in situ evaluation of the cytopathologist necessary to obtain good sampling.

Retrorectal or presacral space is occupied during embryological stem cell development and therefore may contain a heterogeneous group of tumors.We report the case of a 22-year-old male with a pilonidal cyst operated due to recurrent pilonidal sinus cyst. Final diagnosis after pelvic computed tomography is large retrorectal cystic tumor and magnetic resonance diagnosis of a presacral cystic compatible wtih germ cell tumor. The tumor was removed surgically through the abdomen and diagnosis of cystic teratoma was established.Retrorectal tumors are rare lesions whose presence must be ruled out in case of recurrent sinus.Antecedentes: durante el desarrollo embriológico, el espacio retrorrectal o presacro está ocupado por células pluripotenciales y, por tanto, puede contener un grupo heterogéneo de tumores. Caso clínico: se comunica el caso de un paciente masculino de 22 años de edad, intervenido de sinus pilonidal recidivado. Con estudios de tomografía computada de pelvis y resonancia magnética nuclear se sospechó la existencia de un tumor quístico presacro compatible con tumor germinal; la lesión se extirpó quirúrgicamente por vía abdominal y se estableció el diagnóstico definitivo de teratoma quístico. Conclusiones: los tumores retrorrectales son lesiones poco habituales que es necesario descartar en caso de sinus recidivantes.

Minute pulmonary meningothelial-like nodules (MPMNs) are usually unique lesions in the lung parenchyma. Diffuse pulmonary meningotheliomatosis, which is presented as multiple MPMNs, has been less frequently described. MPMNs are mainly asymptomatic and are diagnosed after lung surgery or during autopsy. We report on a patient with multiple and bilateral pulmonary nodules, some of which were cavitated, diagnosed with diffuse pulmonary meningotheliomatosis by transbronchial lung biopsy. Diffuse pulmonary meningotheliomatosis should be included in the differential diagnosis of bilateral lung nodules.

Ewing’s sarcoma family of tumours (ESFT) comprises a group of small round cell tumours (SRCT) genetically defined by specific chromosomal translocations resulting in a fusion of the EWSR1 gene with a member of the ETS family of transcription factors. Atypical ESFT are the most challenging of the ESFT subtypes, and the differential diagnosis with other SRCT of bone and soft tissue is difficult since these subtypes can resemble other neoplasms. The present article describes nine cases of genetically confirmed, atypical ESFT, having unusual alterations at morphological and immunohistochemical (IHC) levels associated with atypical clinical presentation mimicking sarcomas, carcinomas and lymphomas. Present results demonstrate that ESFT showing overlapping morphological and immunohistochemical features with other SRCT of soft tissue and bone, or even with carcinomas or lymphoma, can be differentiated using molecular techniques. In SRCT with EWSR1 translocation demonstrated by FISH, the RT-PCR analysis of specific sarcoma-related gene fusion can offer important clues for the diagnosis of specific entities, especially in tumours with unusual histopathology and/or IHC findings. Thus, we confirm that the integration of clinical, histopathological, IHC and genetic data becomes decisive in the diagnosis of bone and soft tissue sarcomas.