Variations in tumor growth, intra-individual biological variability, and the interpretation of changes.

OBJECTIVES: The identification of changes in tumor markers (TMs) in cancer patients that indicate response to treatment, stabilization or disease progression is a challenge for laboratory medicine. Several approaches have been proposed: assessing percentage increases, applying discriminant values, and estimating half-life (t1/2) or doubling time (DT). In all of them it is assumed that the TM is a surrogate of the variation in tumor size. In general this variation is time-dependent, but this is not the case of intraindividual biological variability (CVi), which can range from 6 % in CA15-3 to 22 % in CA125. When decisions are made on the basis of DT or t1/2, these values can be affected by the CVi; if it is very large, the growth rate very slow and the period of time between determinations very short, the result obtained for DT may be due mainly to the CVi. The aim of this study is to establish the relationship between the CVi and temporal variables. METHODS: We related equations for calculating DT and t1/2 to the reference change values in tumor markers. RESULTS: The application of the formula obtained allows the calculation of the optimal time between measurements to ensure that the influence of the CVi is minimal in different types of tumors and different scenarios. CONCLUSIONS: Intraindividual variation affects the calculation of DT and t1/2. It is necessary to establish the minimum time between two measurements to ensure that the CVi does not affect their calculation or lead to misinterpretation.

Utility of human epididymis protein 4 in the differential diagnosis of ascites.

BACKGROUND AND AIMS: Human epididymal protein 4 (HE4) may be a useful tool in the differential diagnosis of malignant ascites. The aim of this study was to evaluate the diagnostic utility of HE4 for detecting malignant ascites, taking into account the possible false positives identified with adenosine deaminase (ADA), C-reactive protein (CRP), % polynuclear cells (%PMN) and glomerular filtration rate (eGFR). METHODS: Concentrations of HE4, ADA, %PMN and CRP were determined in 114 samples of peritoneal fluid and creatinine in serum in order to calculate eGFR. RESULTS: Concentrations of HE4 presented significant differences (P = 0.028) in benign [median (interquartile range)] [582(372)] pmol/L) and malignant ascites ([8241(367)] pmol/L. Sensitivity was 21.2% and specificity 100%. Significant differences were also observed for HE4 between tumors of gynecological origin ([3165(8769)] pmol/L) and others ([665(663)] pmol/L), with a sensitivity of 67% and a specificity of 100%. Classifying according to possible false positives (ADA > 45U/L, CRP > 50 mg/L, %PMN > 90 and eGFR < 30 mL/min/1.73 m2) at maximum specificity, a sensitivity of 33.3% was obtained for HE4, with a cut-off point of 2660 pmol/L. Without possible false positives (ADA < 45U/L, CRP < 50 mg/L, %PMN < 90 and eGFR ≥ 30 mL/min/1.73 m2), a sensitivity of 37.7% was obtained at 100% specificity for a cut-off point of 1041 pmol/L. Applying these criteria to the entire group, a sensitivity of 36.4% was obtained at maximum specificity. CONCLUSIONS: HE4 allows the identification of malignant ascites with moderate sensitivity at maximum specificity. HE4 levels can differentiate between tumors of gynecological origin and others. Classification according to possible false positives increases sensitivity without losing specificity.

Lung cancer tumor markers in serous effusions and other body fluids.

From its onset and during its progression, lung cancer may affect various extrapulmonary structures. These include the serous membranes, the pleura and pericardium, and less frequently the central nervous system, with leptomeningeal involvement. In these cases, fluid accumulates in the serous membranes which may contain substances secreted by the tumor. Measuring the concentrations of these substances can provide useful information for elucidating the origin of the fluid accumulation, either in pleural and pericardial effusions or in cerebrospinal fluid. This paper describes the histological types of lung cancer that most frequently affect the serosa and leptomeninges. It also reviews the literature on tumor markers in different fluids and makes recommendations for their interpretation.

[The joint management of Geriatrics-Neurosurgery of patients older than 75 years reduces the average stay, morbidity, hospital readmissions and mortality per year]. / El manejo conjunto Geriatría-Neurocirugía de pacientes mayores de 75 años reduce la estancia media, la morbilidad, los reingresos hospitalarios y la mortalidad al año.

OBJECTIVE: Population ageing is a reality for which national health systems are not adapted. The World Health Organisation has already raised awareness about the implementation of specific measures, from undergraduate training to dedicated elderly care units, to tackle this situation. In this article, the aim is to analyse the potential benefits of geriatric monitoring on elderly neurosurgical patients. MATERIAL AND METHODS: A descriptive analysis was performed in this medical centre, comparing the information collected from elderly patients (over 75 years of age) admitted into the neurosurgical department during 2periods: June 2015 to February 2017, in which a shared geriatric monitoring was implemented, and between October 2013 and May 2015, equivalent period, in which only the geriatrician performed the evaluation of the patients' general condition, before referring them to other social-healthcare units. A number of factors were considered, including mean age, gender, the neurosurgical condition that led to admission, mean stay, infectious complications, acute confusional syndrome, admission into an intensive care unit, need for support from other medical departments, reoperations, mortality during hospitalisation, referral to social-health units, readmission within a month, and mortality within a year. RESULTS: A total of 173 patients on shared monitoring were compared to 189 patients from the previous period. Both groups had similar demographic characteristics. During the analysis, a significant reduction was observed in shared monitoring as regards, mean hospitalisation, infectious complications, admissions into an intensive care unit, the need for support from other medical departments, readmissions within a month, and mortality within a year. CONCLUSIONS: On patients of over 75 years of age, shared geriatric-neurosurgical monitoring reduces mean hospitalisation, morbidity, the need for support from other medical departments, early readmission, and mortality within a year. This strategy prioritises patient care, reduces costs, and rationalises resources.

Neurosarcoidosis presenting with isolated intracranial mass lesion and communicating hydrocephalus.

Isolated neurosarcoidosis is a very rare disease, which makes up 5-15% of sarcoidosis cases. Hydrocephalus is a rare clinical feature with a prevalence of 6% among these patients. Considering neurosarcoidosis in the differential diagnosis of a unique parenquimal mass lesion could help in the early identification of this disease. We report the case of a 27-year-old African man who developed with a sole intracranial mass lesion mimicking radiologically a glioma, which finally came out as an isolated neurosarcoidosis. There is a difficulty in diagnosis when isolated neurosarcoidosis appears. In addition, the low prevalence of the disease entails a not standardized medical treatment. Natural outcome is poor even when hydrocephalus is resolved. Multimodal treatments including complete pharmacological treatment do not seem to assure a better outcome in these patients until date.

Are Modic Changes Able to Help Us in Our Clinical Practice? A Study of the Modic Changes in Young Adults During Working Age.

STUDY DESIGN: Modic changes [vertebral endplate spinal changes (VESC)] have been related to degenerative disk disease, and in past decades it was thought that their presence justified the surgical treatment, in particular spinal fusion. OBJECTIVE: The aim of the present study is to investigate its prevalence and features in a population of young workers suffering from low back pain, and explore the eventual relationship with the treatment applied in each case. BACKGROUND DATA: We conducted a retrospectively review of 450 magnetic resonance images from our hospital, in patients with low back pain or sciatica and age below 40. MATERIALS AND METHODS: Age, sex, symptoms predominance, concurrence with other spine disease, VESC type, evolution, level/s of involvement and placement, affected disk location and extent of the disease, disk height, and status of the endplate were recorded. The applied treatment was divided in groups according to the degree of invasiveness of the procedure. RESULTS: Prevalence of VESC was 13.05% predominant in patients over 30 years, and 100% associated to disk degenerative changes. Most frequent features were: type I (54%), lower lumbar region (98%), along with a decreased disk height (68%), and distortion of the disk endplates (98%, P<0.01). The patients with VESC presented a favorable outcome with conservative treatment, but were more frequently associated with invasive treatment, compared with non-VESC patients (P<0.024). CONCLUSIONS: VESC prevalence increases with age, underlying the degenerative causative etiology. Surgical indication should not be stated on the basis of the VESC findings alone, the main factor for indicating surgery depends more on other associated degenerative spinal changes.

Neuroendoscopic treatment for hydrocephalus associated to midline arachnoid cysts in a series of nine pediatric patients.

BACKGROUND: Arachnoid cysts are extra-axial cerebrospinal fluid (CSF) collections surrounded by a membrane. Occasionally, hydrocephalus is associated due to a change in CSF circulatory dynamics. Neuroendoscopic treatment has been recommended for patients who develop symptoms resulting from the cyst location. METHODS: We retrospectively evaluate the results in our series of 9 patients with hydrocephalus associated to midline arachnoid cysts treated endoscopically. Success was rated on a scale of five degrees of neuroendoscopical success. RESULTS: We performed endoscopic third ventriculostomy (ETV) in three cases; ETV was associated to ventriculocystostomy (VC) in three cases; ETV, VC and septostomy (SPT) were performed in one patient; neuroendoscopic Monro foraminoplasty (NEFPMO) plus SPT were associated in one case; last patient was performed ETV, VC and cystocysternostomy (CC). For first procedures, 6 patients completed permanent Success (grade I). In one case success was transitory (grade II) and required a second procedure (ETV). In one patient VC success and ETV failure implied partial success (grade III). One patient's early failure (grade V) required a second procedure (ETV + NEFPMO). Success in second procedures was grade I in both patients. Follow-up period was over 12 months and altogether success was grade I in 8/9 patients and grade III in 1/9 patients. Shunt independency went over 88%. CONCLUSIONS: Endoscopy allows a solution avoiding the implantation of cerebrospinal fluid shunt devices. When possible, we likely approach both, hydrocephalus and arachnoid cyst, with different endoscopic maneuvers in a single procedure. It is important to expand the usage of success classifications for combined procedures.

Prognosis of atypical teratoid rhabdoid tumors (AT/RT) treated with multimodal therapy protocols. Report of our series.

OBJECTIVE: Atypical teratoid rhabdoid tumors (AT/RT) of the central nervous system are rare, very aggressive embryological tumors, typically diagnosed in young patients and having a low survival rate after diagnosis. The aim of this study was to emphasize, based on the latest results in the literature, the need for protocols for multidisciplinary treatment in these patients. MATERIAL AND METHODS: We report our series of 3 cases treated, diagnosed and followed up between 2009 and 2014. They were treated with multimodal therapy protocols (Rhabdoid SIOP-2007 and European Rhabdoid Registry EU-RHAB-2010). In addition, we carried out a literature review. RESULTS: Two of our 3 cases (supratentorial and spinal tumors) did not show any progression of the disease after long follow-up, in contrast with most of the cases available in the literature. The second patient had a shorter survival. CONCLUSIONS: Patient age at the time of diagnosis, supratentorial location of the mass and fewer complications with adjuvant treatments seem to be factors yielding good prognosis for AT/RT tumors. In agreement with the latest international protocols, multidisciplinary treatment is the ideal treatment, consisting of radiotherapy and chemotherapy after complete tumor resection.

Ethmoidal meningoencephalocele and CSF leak after posthaemorrhagic ventricular dilatation in a newborn child.

BACKGROUND: Rhinoliquorrhoea suggests a communication between the subarachnoid space and the sinonasal tract. Clinical presentation includes clear nasal discharge, headache, pneumocephalus, meningitis or brain abscess. Cerebrospinal fluid (CSF) leaks are mostly of traumatic origin (skull base fractures), iatrogenic (secondary to endoscopic endonasal surgery) or associated with tumour aetiology. Occasionally, hydrocephalus has been the cause of rhinoliquorrhoea in adults, presumably secondary to the chronically raised intracranial pressure with skull base erosion and meningocele. To our knowledge, the association of hydrocephalus and ethmoid meningoencephalocele/CSF leak has not been previously reported in a newborn child. CASE PRESENTATION: We present the case of a 9-month-old girl who was referred for rhinorrhoea. She had a history of posthaemorrhagic ventricular dilatation. Brain computed tomography (CT) and magnetic resonance imaging (MRI) showed a left ethmoidal meningoencephalocele and small ventricular size. The meningoencephalocele was surgically repaired using an intradural subfrontal approach. During the postoperative period, after the transient lumbar drain was withdrawn, she developed symptomatic hydrocephalus. Ventriculoperitoneal shunting was required. CONCLUSION: Progressive ventricular dilatation may arise from a meningoencephalocele/CSF leak in paediatric patients. Early identification and repair of the meningoencephalocele are critical to avoid development of complications.

Endoscopic endonasal resection of clival xanthoma: case report and literature review.

Bone xanthoma is an extremely rare and benign tumor in terms of its nature and growth over time. We describe the first case coexisting with ventriculomegaly secondary to aqueduct stenosis (non-tumoral hydrocephalus), the second xanthoma of the clivus described to date. The patient was a 51-year-old woman with headaches and absence seizures. Axial T1-weighted MRI showed a well-demarcated, hypointense, osteolytic, 25 × 18 × 15 mm lesion with cortical erosion located at the right margin of the clivus. Sagittal T2-weighted MRI demonstrated a hypointense mass without associated edema. Sagittal gadolinium-enhanced T1-weighted MRI showed contrast uptake with a partially hypointense rim. The increased ventricular size without periventricular edema was associated with aqueduct stenosis, and there was no contiguity with the tumor. A neuronavigation image-guided transsphenoidal approach was chosen to perform a macroscopically complete resection. Intraoperative histopathological study showed a chordoma of the clivus. Exhaustive postsurgical study revealed the benign nature of a bone xanthoma. Given the finding of a clival lesion, the differential diagnosis is essentially with other malignant entities with a rapidly fatal outcome, such as metastases, or with a possible invasive evolution, such as clivus chordomas. This report describes the clinical, radiological, and pathological keys for such differentiation in order to avoid unnecessarily aggressive treatment with ablative surgery and radiotherapy.

Predicting the "usefulness" of 5-ALA-derived tumor fluorescence for fluorescence-guided resections in pediatric brain tumors: a European survey.

BACKGROUND: Five-aminolevulinic acid (Gliolan, medac, Wedel, Germany, 5-ALA) is approved for fluorescence-guided resections of adult malignant gliomas. Case reports indicate that 5-ALA can be used for children, yet no prospective study has been conducted as of yet. As a basis for a study, we conducted a survey among certified European Gliolan users to collect data on their experiences with children. METHODS: Information on patient characteristics, MRI characteristics of tumors, histology, fluorescence qualities, and outcomes were requested. Surgeons were further asked to indicate whether fluorescence was "useful", i.e., leading to changes in surgical strategy or identification of residual tumor. Recursive partitioning analysis (RPA) was used for defining cohorts with high or low likelihoods for useful fluorescence. RESULTS: Data on 78 patients <18 years of age were submitted by 20 centers. Fluorescence was found useful in 12 of 14 glioblastomas (85 %), four of five anaplastic astrocytomas (60 %), and eight of ten ependymomas grades II and III (80 %). Fluorescence was found inconsistently useful in PNETs (three of seven; 43 %), gangliogliomas (two of five; 40 %), medulloblastomas (two of eight, 25 %) and pilocytic astrocytomas (two of 13; 15 %). RPA of pre-operative factors showed tumors with supratentorial location, strong contrast enhancement and first operation to have a likelihood of useful fluorescence of 64.3 %, as opposed to infratentorial tumors with first surgery (23.1 %). CONCLUSIONS: Our survey demonstrates 5-ALA as being used in pediatric brain tumors. 5-ALA may be especially useful for contrast-enhancing supratentorial tumors. These data indicate controlled studies to be necessary and also provide a basis for planning such a study.

Estudio preliminar de casos y controles de la morfología axial L4-L5 en la hernia de disco / Preliminary case-control study of axial L4- L5 morphology in disc herniation

Una de las cuestiones discutidas es el papel de los factores genéticos y adquiridos en la etiologia de la hernia de disco. Como expresión genómica, el estudio de la morfología podría clarificar dicho papel. Las recientes técnicas de morfometría geométrica (análisis Procrustes generalizado y estudio de componentes principales, entre otras) permiten analizar la forma desde un enfoque no euclidiano, brindando una nueva via de investigación que puede ser aplicada en el raquis. En el presente trabajo empleamos técnicas de morfometría geométrica para analizar la forma axial L4-L5 en pacientes con hernia de disco (n = 69) y controles sanos (n = 87). Se observó una variabilidad de forma a modo de expansión-contracción coronal, a partir del centro del canal medular. Se hallaron diferencias morfológicas entre los controles y las hernias: potenciales factores de riesgo que afectaron principalmente a las láminas y la orientación interapofisaria, condicionando cambios en la morfología del canal. Los resultados apoyan un origen genético de la variabilidad morfológica, con un importante dimorfismo sexual. No obstante, el cambio más relevante para la discriminación la presencia y la ausencia de hernia fue el tamaño del disco, que varió significativamente con el peso. Nuestros hallazgos contribuyen a mejorar el conocimiento morfológico espinal, y a entender el papel de la forma en la hernia de disco, como expresión de la genética, frente a otros factores etiológicos adquiridos. Las técnicas de morfometría geométrica ofrecen una prometedora vía para la investigación de la columna, recomendándose un mayor uso dada la escasez de publicaciones al respecto...

The effect of game-based exercise on infant acute lymphocytic leukaemia patients / Efecto del ejercicio físico basado en el juego en la leucemia linfocítica aguda

Objective. To establish the effect of a game-based exercise programme on Physical Deconditioning Syndrome (PDS) in 5 to 12 year-old children suffering Acute Lymphocytic Leukaemia (ALL). Materials and methods. This was a quasi-experimental study involving seven children being treated for ALL at the National Cancer Institute (NCI) in Bogotá, Colombia. Fitness determinants (aerobic capacity, muscle strength, flexibility, motor skills and proprioception) were initially assessed to establish their exercise regime category, classifying subjects into three levels. Post-intervention assessment at the end of the programme verified changes in such determinants. Results. Seven children aged 5 to 12 years-old (9±2.13 years) suffering from ALL (4 girls and 3 boys) met the inclusion criteria. Most determinants underwent changes leading to an increase in patients' evaluation scores (except for muscle strength, which remained constant). Whilst determinant variation was important, a greater difference was found when the overall score was analysed (p=0.05), signifying that the intervention had changed these children's health status. Conclusion. Game-based exercise was useful for managing PDS in 5 to12 year-old ALL patients and suggested new ways of providing an intervention concerning physical therapy. However, studies involving a larger target population and longer intervention time are needed to identify new findings in this field.

Objetivo. Establecer el efecto de un programa de ejercicio físico (EF) basado en el juego sobre el Síndrome de Desacondicionamiento Físico (SDF) de niños con Leucemia Linfocítica Aguda (LLA) entre 5-12 años. Materiales y métodos. Se realizó un estudio cuasi-experimental con la participación de siete niños tratados por LLA en el Instituto Nacional de Cancerología (INC). Se hizo una evaluación inicial de los determinantes de la condición física (capacidad aeróbica, fuerza muscular, flexibilidad, destreza motora y propiocepción) para establecer la categoría de intervención de EF, clasificando a los sujetos en tres niveles. Al finalizar el programa se ejecutó una evaluación post-intervención para verificar cambios en dichos determinantes. Resultados. Siete niños con LLA (4 niñas y 3 niños) reunieron los criterios de inclusión, con edades entre 5 y 12 años (9±2,13 años). La mayoría de determinantes experimentó cambios en su puntuación, ascendiendo en calificación, a excepción del determinante de fuerza muscular, que se mantuvo constante. Si bien la variación por determinante fue importante, se encontró una mayor diferencia e impacto al analizar el puntaje global de la Batería evaluativa (p-valor 0,05), lo que representa que la intervención produjo un cambio en la condición de salud de los niños intervenidos. Conclusión. El EF basado en el juego es útil para el manejo del SDF de niños con LLA entre 5-12 años y abre la puerta a nuevas formas de intervención fisioterapéutica. Sin embargo, es necesario implementar estudios con mayor número poblacional y tiempo de intervención que permitan identificar nuevos hallazgos en el área.

COMPARACIÓN ENTRE EL POTENCIAL DE LAS REGIONES VARIABLES DEL 16s RDNA PARA LA IDENTIFICACIÓN DE Lactobacillus spp. (LACTOBACILLIACEAE) / COMPARING THE POTENTIAL FOR IDENTIFICATION OF Lactobacillus spp. OF 16s RDNA VARIABLE REGIONS

El 16s rDNA es utilizado para la identificación bacteriana dada su tasa de variación entre especies. Algunas de las regiones variables de la subunidad ribosomal son más informativas que otras por lo cual en este estudio se evalúa el potencial de identificación aportado por cada región y combinaciones entre ellas. Se extrajeron las regiones variables V1 a la V8 del 16s rDNA de diferentes cepas y especies de Lactobacillus y se analizaron mediante los paquetes de STAP (ss-RNA Taxonomy Assigning Pipeline) y RDP (Ribosomal Database Project) multiclassifier. Adicionalmente se evaluaron árboles filogenéticos de máxima verosimilitud. Nuestros resultados muestran que la mayoría de regiones variables logran dar una correcta clasificación hasta género, sin embargo no son suficientes para clasificar hasta especie usando STAP. La región que presenta el mayor número de amplímeros es V5V6, sin embargo es la que presenta la mayor cantidad de falsos negativos. La que presenta el mayor número de verdaderos positivos es V1V3 (especie) para STAP y V5V8(género) para RDP. Las filogenias evaluadas mostraron que la topología de referencia se puede obtener con diferentes combinaciones de regiones variables e.g., V1V3 y V1V8. El estudio experimental de las cepas contenidas en un tampón comercial mostró que el amplicón V1V8 y el V1V3 dan una misma clasificación correcta. Proponemos la región V1V3 como la región mínima para clasificación correcta de Lactobacillus spp.. En conclusión, la región mínima para clasificar especies del género Lactobacillus es la V1V3, la cual es útil para estudios metagenómicos de muestras de probióticos.

16s rDNA is used for bacterial identification because its variation rate between species allows differentiation. The gene for this ribosomal subunit has 9 variable regions and some of them give more information than others. We were interested in evaluating the potential for species identification of each region and their combinations. We extracted the V1 to V8 regions of 16s rDNA from different strains and species of Lactobacillus and analyzed them using STAP (ss-RNA Taxonomy Assigning Pipeline) and RDP (Ribosomal Database Project) multiclassifier packages. Phylogenetic trees obtained by maximum likelihood analyses were compared. Classification results show that many regions give the correct genus classification using RDP and STAP, however they are not enough to classify up to the level of species. V5V6 region presents the highest quantity of informative fragments but also present the highest rate of false negatives. V1V3 region presents the highest rate of true positives (species) using STAP and the region V5V8 in RDP (genus).The phylogenetic result shows that the reference topology could be obtained using different combination of regions as V1V3 and V1V8.The experimental validation was done using commercial strains from a probiotic tampon. Sequencing analysis show that the V1V3 region gives the same information and result as the complete 16s rDNA; the three isolated strains correspond to the strains indicated in the product. We conclude that the V1V3 region is the minimum required region to classify Lactobacillus spp. in the correct way and this region is useful in metagenomics to analyze probiotics samples.

[Cranial fasciitis: a case report and review of the literature]. / Fascitis craneal: caso clínico y revisión de la literatura.

Cranial fasciitis is an uncommon, rapidly-growing, benign, non-tumoural, myofibroblastic lesion of the skull, found mainly among young children in their first year of life. It is histologically similar to nodular fasciitis and pseudosarcomatous fasciitis. It may mimic more aggressive pathologies, such as sarcomatosis or histiocytosis, due to its rapid, nodular growth in subcutaneous tissue. Complete resection is considered curative and, therefore, entails a low risk of metastases or malignant recurrences. We present the clinical, radiological and pathological findings in a 4-year-old boy with cranial fasciitis in the deep, subcutaneous, soft tissue, with erosion of the outer table of the cranium, which also produced periosteal reaction, while respecting the inner table and meninges. The objective of this article is to highlight the absence of radiotherapeutic or chemotherapeutic adjuvant treatment. In addition, an exhaustive review of the literature is also presented.

[Sciatica secondary to extrapelvic endometriosis affecting the piriformis muscle. Case report]. / Ciatalgia secundaria a endometriosis extrapélvica del músculo piriforme. A propósito de un caso.

OBJECTIVE: We present a case report of symptomatic compression of the right sciatic nerve notch, secondary to piriformis muscle endometriosis, as well as a literature review. MATERIAL AND METHODS: We report the case of a 29-year-old woman with 2-year evolution of right chronic sciatica. During the first year, symptoms were episodic and associated with menstruation. During the second year, sciatica was constant and associated with gait disorder due to sciatic musculature weakness. Mononeuropathy was proved by a neurophysiological study, with MRI and PET studies revealing a mass in the sciatic notch and regional pathological increase in metabolic activity. Surgical treatment was performed in order to release the nerve and obtain a histological sample. RESULTS: The patient was treated by a transgluteal approach, with external neurolysis of the sciatic nerve and resection of an old-blood cyst at the level of the piriformis muscle. This was subsequently reported as endometriosis by histological examination. The sciatica was resolved after surgery. CONCLUSIONS: Extrapelvic sciatic nerve compression by adjacent endometriosis is very infrequent. Muscle denervation and lack of a histological diagnosis led to surgical exploration of the compression area in order to release the nerve, resect the cause of compression and obtain a definitive diagnosis. The procedure improved all symptoms.