Clinical and therapeutic variables may influence the association between infarct core predicted by CT perfusion and clinical outcome in acute stroke.

OBJECTIVES: After an acute ischemic stroke, patients with a large CT perfusion (CTP) predicted infarct core (pIC) have poor clinical outcome. However, previous research suggests that this relationship may be relevant for subgroups of patients determined by pretreatment and treatment-related variables while negligible for others. We aimed to identify these variables. METHODS: We included a cohort of 828 patients with acute proximal carotid arterial occlusions imaged with a whole-brain CTP within 8 h from stroke onset. pIC was computed on CTP Maps (cerebral blood flow < 30%), and poor clinical outcome was defined as a 90-day modified Rankin Scale score > 2. Potential mediators of the association between pIC and clinical outcome were evaluated through first-order and advanced interaction analyses in the derivation cohort (n = 654) for obtaining a prediction model. The derived model was further validated in an independent cohort (n = 174). RESULTS: The volume of pIC was significantly associated with poor clinical outcome (OR = 2.19, 95% CI = 1.73 - 2.78, p < 0.001). The strength of this association depended on baseline National Institute of Health Stroke Scale, glucose levels, the use of thrombectomy, and the interaction of age with thrombectomy. The model combining these variables showed good discrimination for predicting clinical outcome in both the derivation cohort and validation cohorts (area under the receiver operating characteristic curve 0.780 (95% CI = 0.746-0.815) and 0.782 (95% CI = 0.715-0.850), respectively). CONCLUSIONS: In patients imaged within 8 h from stroke onset, the association between pIC and clinical outcome is significantly modified by baseline and therapeutic variables. These variables deserve consideration when evaluating the prognostic relevance of pIC. KEY POINTS: •The volume of CT perfusion (CTP) predicted infarct core (pIC) is associated with poor clinical outcome in acute ischemic stroke imaged within 8 h of onset. •The relationship between pIC and clinical outcome may be modified by baseline clinical severity, glucose levels, thrombectomy use, and the interaction of age with thrombectomy. •CTP pIC should be evaluated in an individual basis for predicting clinical outcome in patients imaged within 8 h from stroke onset.

Addition of intracranial aspiration to balloon guide catheter does not improve outcomes in large vessel occlusion anterior circulation stent retriever based thrombectomy for acute stroke.

BACKGROUND: Balloon guide catheter (BGC) in stent retriever based thrombectomy (BGC+SR) for patients with large vessel occlusion strokes (LVOS) improves outcomes. It is conceivable that the addition of a large bore distal access catheter (DAC) to BGC+SR leads to higher efficacy. We aimed to investigate whether the combined BGC+DAC+SR approach improves angiographic and clinical outcomes compared with BGC+SR alone for thrombectomy in anterior circulation LVOS. METHODS: Consecutive patients with anterior circulation LVOS from June 2019 to November 2020 were recruited from the ROSSETTI registry. Demographic, clinical, angiographic, and outcome data were compared between patients treated with BGC+SR alone versus BGC+DAC+SR. The primary outcome was first pass effect (FPE) rate, defined as near complete/complete revascularization (modified Thrombolysis in Cerebral Infarction (mTICI) 2c-3) after single device pass. RESULTS: We included 401 patients (BGC+SR alone, 273 (66.6%) patients). Patients treated with BGC+SR alone were older (median age 79 (IQR 68-85) vs 73.5 (65-82) years; p=0.033) and had shorter procedural times (puncture to revascularization 24 (14-46) vs 37 (24.5-63.5) min, p<0.001) than the BGC+DAC+SR group. Both approaches had a similar FPE rate (52% in BGC+SR alone vs 46.9% in BGC+DAC+SR, p=0.337). Although the BGC+SR alone group showed higher rates for final successful reperfusion (mTICI ≥2b (86.8% vs 74.2%, p=0.002) and excellent reperfusion, mTICI ≥2 c (76.2% vs 55.5%, p<0.001)), there were no significant differences in 24 hour National Institutes of Health Stroke Scale score or rates of good functional outcome (modified Rankin Scale score of 0-2) at 3 months across these techniques. CONCLUSIONS: Our data showed that addition of distal intracranial aspiration catheters to BGC+SR based thrombectomy in patients with acute anterior circulation LVO did not provide higher rates of FPE or improved clinical outcomes.

Percutaneous cryoablation of chondroblastoma and osteoblastoma in pediatric patients.

BACKGROUND: To review the safety and efficacy of percutaneous cryoablation for the treatment of chondroblastoma and osteoblastoma in the pediatric and adolescent population. MATERIALS AND METHODS: A retrospective review from 2016 to 2020 was performed to evaluate clinical and imaging response to percutaneous cryoablation in 11 symptomatic patients with diagnosis of chondroblastoma and osteoblastoma treated from two pediatric hospitals with at least 12-month follow-up. Technical success (correct needle placement and potential full coverage of the tumor with the planned ablation zone) and clinical success (relief of the symptoms) were evaluated. The primary objective was to alleviate pain related to the lesion(s). Immediate and late complications were recorded. Patients were followed in clinic and with imaging studies such as MRI or CT for a minimum of 6 months. RESULTS: A total of 11 patients were included (mean 14 years, age range 9-17; male n = 8). Diagnoses were osteoblastoma (n = 4) and chondroblastoma (n = 7). Locations were proximal humerus (n = 1), femur condyle (n = 1), and proximal femur (n = 1) tibia (n = 3), acetabulum (n = 3), thoracic vertebra (n = 1) and lumbar vertebra (n = 1). Cryoablation was technically successful in all patients. Clinical success (cessation of pain) was achieved in all patients. No signs of recurrence were observed on imaging follow-up in any of the patients. One of the patients developed periprocedural right L2-L3 transient radiculopathy as major immediate complication. CONCLUSIONS: Percutaneous image-guided cryoablation can be considered potentially safe and effective treatment for chondroblastoma and osteoblastoma in children and adolescents.

Clinical and Pathological Evidence of Anti-GD2 Immunotherapy Induced Differentiation in Relapsed/Refractory High-Risk Neuroblastoma.

BACKGROUND: Neuroblastic tumors (NBTs) originate from a block in the process of differentiation. Histologically, NBTs are classified in neuroblastoma (NB), ganglioneuroblastoma (GNB), and ganglioneuroma (GN). Current therapy for high-risk (HR) NB includes chemotherapy, surgery, radiotherapy, and anti-GD2 monoclonal antibodies (mAbs). Anti-GD2 mAbs induce immunological cytoxicity but also direct cell death. METHODS: We report on patients treated with naxitamab for chemorefractory NB showing lesions with long periods of stable disease. Target lesions with persisting 123I-Metaiodobenzylguanidine (MIBG) uptake after 4 cycles of immunotherapy were further evaluated by functional Magnetic Resonance Imaging (MRI) and/or Fluorodeoxyglucose (FDG)-positron emission tomography (PET). MIBG avid lesions that became non-restrictive on MRI (apparent diffusion coefficient (ADC) > 1) and/or FDG-PET negative (SUV < 2) were biopsied. RESULTS: Twenty-seven relapse/refractory (R/R) HR-NB patients were enrolled on protocol Ymabs 201. Two (7.5%) of the 27 showed persistent bone lesions on MIBG, ADC high, and/or FDG-PET negative. Forty-four R/R HR-NB patients received chemo-immunotherapy. Twelve (27%) of the 44 developed persistent MIBG+ but FDG-PET- and/or high ADC lesions. Twelve (86%) of the 14 cases identified were successfully biopsied producing 16 evaluable samples. Histology showed ganglioneuroma maturing subtype in 6 (37.5%); ganglioneuroma mature subtype with no neuroblastic component in 4 (25%); differentiating NB with no Schwannian stroma in 5 (31%); and undifferentiated NB without Schwannian stroma in one (6%). Overall, 10 (62.5%) of the 16 specimens were histopathologically fully mature NBTs. CONCLUSIONS: Our results disclose an undescribed mechanism of action for naxitamab and highlight the limitations of conventional imaging in the evaluation of anti-GD2 immunotherapy clinical efficacy for HR-NB.

Elevated glucose is associated with hemorrhagic transformation after mechanical thrombectomy in acute ischemic stroke patients with severe pretreatment hypoperfusion.

Several pretreatment variables such as elevated glucose and hypoperfusion severity are related to brain hemorrhage after endovascular treatment of acute stroke. We evaluated whether elevated glucose and severe hypoperfusion have synergistic effects in the promotion of parenchymal hemorrhage (PH) after mechanical thrombectomy (MT). We included 258 patients MT-treated who had a pretreatment computed tomography perfusion (CTP) and a post-treatment follow-up MRI. Severe hypoperfusion was defined as regions with cerebral blood volume (CBV) values < 2.5% of normal brain [very-low CBV (VLCBV)-regions]. Median baseline glucose levels were 119 (IQR = 105-141) mg/dL. Thirty-nine (15%) patients had pretreatment VLCBV-regions, and 42 (16%) developed a PH after MT. In adjusted models, pretreatment glucose levels interacted significantly with VLCBV on the prediction of PH (p-interaction = 0.011). In patients with VLCBV-regions, higher glucose was significantly associated with PH (adjusted-OR = 3.15; 95% CI = 1.08-9.19, p = 0.036), whereas this association was not significant in patients without VLCBV-regions. CBV values measured at pretreatment CTP in coregistered regions that developed PH or infarct at follow-up were not correlated with pretreatment glucose levels, thus suggesting the existence of alternative deleterious mechanisms other than direct glucose-driven hemodynamic impairments. Overall, these results suggest that both severe hypoperfusion and glucose levels should be considered in the evaluation of adjunctive neuroprotective strategies.

"Incidence and Clinico-Radiological Correlations of Early Arterial Reocclusion After Successful Thrombectomy in Acute Ischemic Stroke".

About half of acute stroke patients treated with mechanical thrombectomy (MT) do not show clinical improvement despite successful recanalization. Early arterial reocclusion (EAR) may be one of the causes that explain this phenomenon. We aimed to analyze the incidence and clinico-radiological correlations of EAR after successful MT. A consecutive series of patients treated with MT between 2010 and 2018 at a single-center included in a prospective registry was retrospectively reviewed. Specific inclusion criteria for the analysis were (1) successful recanalization after MT and (2) availability of pretreatment CT perfusion and follow-up MRI. EAR was evaluated in the follow-up MR angiography. Adjusted regression models were used to analyze the association of EAR with pretreatment variables, infarct growth, final infarct volume, and clinical outcome at 90 days (ordinal distribution of the modified Rankin Scale scores). Out of 831 MT performed, 218 (26%) patients fulfilled inclusion criteria, from whom 13 (6%) suffered EAR. In multivariate analysis controlled by confounders, EAR was independently associated with poor clinical outcome (aOR = 3.2, 95%CI = 1.16-9.72, p = 0.039), greater final infarct volume (aOR = 3.8, 95%CI = 1.93-7.49, p < 0.001), and increased infarct growth (aOR = 8.5, CI95% = 2.04-34.70, p = 0.003). According to mediation analyses, the association between EAR and poor clinical outcome was mainly explained through its effects on final infarct volume and infarct growth. Additionally, EAR was associated with non-cardioembolic etiology (adjusted Odds Ratio (aOR) = 10.1, 95%CI = 1.25-81.35, p = 0.030) and longer procedural time (aOR = 2.6, 95%CI = 1.31-5.40, p = 0.007). Although uncommon, EAR hampers the benefits of successful recanalization after MT resulting in increased infarct growth and larger final lesions.

The accuracy of ischemic core perfusion thresholds varies according to time to recanalization in stroke patients treated with mechanical thrombectomy: A comprehensive whole-brain computed tomography perfusion study.

Computed tomography perfusion (CTP) allows the estimation of pretreatment ischemic core after acute ischemic stroke. However, CTP-derived ischemic core may overestimate final infarct volume. We aimed to evaluate the accuracy of CTP-derived ischemic core for the prediction of final infarct volume according to time from stroke onset to recanalization in 104 patients achieving complete recanalization after mechanical thrombectomy who had a pretreatment CTP and a 24-h follow-up MRI-DWI. A range of CTP thresholds was explored in perfusion maps at constant increments for ischemic core calculation. Time to recanalization modified significantly the association between ischemic core and DWI lesion in a non-linear fashion (p-interaction = 0.018). Patients with recanalization before 4.5 h had significantly lower intraclass correlation coefficient (ICC) values between CTP-predicted ischemic core and DWI lesion (n = 54; best threshold relative cerebral blood flow (rCBF) < 25%, ICC = 0.673, 95% CI = 0.495-0.797) than those with later recanalization (n = 50; best threshold rCBF < 30%, ICC = 0.887, 95% CI = 0.811-0.935, p = 0.013), as well as poorer spatial lesion agreement. The significance of the associations between CTP-derived ischemic core and clinical outcome at 90 days was lost in patients recanalized before 4.5 h. CTP-derived ischemic core must be interpreted with caution given its dependency on time to recanalization, primarily in patients with higher chances of early recanalization.

Greater infarct growth limiting effect of mechanical thrombectomy in stroke patients with poor collaterals.

OBJECTIVE: Stroke patients with good collateral circulation achieve the best recovery after mechanical thrombectomy (MT) but strict imaging selection may result in untreated patients that could benefit from MT. We assessed whether the extent of collaterals had modifying effects on the amount of ischemic tissue saved from infarction with MT over best medical treatment (BMT). METHODS: This was a single center cohort of consecutive patients (n=339) with proximal occlusions in the carotid territory. Patients were categorized according to a four point category scale on CT angiography as having good (scores 2-3) or poor (scores 0-1) collaterals. The primary outcome measure was the interaction between collaterals and MT on infarct growth. The secondary outcome assessed the treatment effect of MT over BMT on functional status in relation to collateral status. Safety outcomes were mortality and symptomatic intracranial hemorrhage. RESULTS: Collaterals had a modifying effect of MT on infarct growth (P=0.004), with a greater reduction in 96 patients with poor collaterals (38.8 mL) than in 243 patients with good collaterals (1.9 mL). There was also a significant (P<0.001) interaction between the effect of MT and functional outcome in relation to collateral status, with more benefits of MT in patients with poor collaterals. MT was associated with lower mortality than BMT in patients with poor collaterals only. CONCLUSION: Compared with BMT, the use of MT in the early time window in large vessel stroke results in a more substantial limitation of infarct growth in patients with poor collaterals.

Usefulness of MDCT to Differentiate Between Renal Cell Carcinoma and Oncocytoma: Development of a Predictive Model.

OBJECTIVE: The objective of our study was to identify the most useful parameters to differentiate between renal cell carcinoma (RCC) and oncocytoma using four-phase CT. MATERIALS AND METHODS: Ninety-seven patients with solid renal lesions who underwent surgery with four-phase preoperative CT evaluation and with pathologic diagnosis of RCC or oncocytoma were included in the study. Features of tumors and the enhancement pattern in the four CT phases were evaluated and analyzed. Logistic regression models were used to assess independent predictors for malignancy. RESULTS: Histopathologically, 13 tumors were oncocytomas and 84 were RCCs. RCCs were larger (6.20 cm vs 3.21 cm, p = 0.0004) and more often enhanced heterogeneously (66 vs 6, p = 0.02). Lesions that were larger than 4 cm showed a significantly higher risk of malignancy (p = 0.0046). Significant differences were found in intensity of nodule enhancement between the nephrographic and the excretory phases with respect to the unenhanced phase (p = 0.003 and p = 0.0026). At multivariate analysis, parameters that were independent predictors of malignancy were enhancement pattern, with RCCs more often having heterogeneous enhancement than oncocytomas (odds ratio [OR], 0.18; 95% CI, 0.04-0.90), and nodule enhancement in the excretory phase in relation to the unenhanced phase, with RCCs showing lower enhancement (OR, 0.93; 95% CI, 0.88-0.97), and a size larger than 4 cm (OR, 4.01; 95% CI, 0.70-23.14). CONCLUSION: The combination of different CT parameters including lesion size larger than 4 cm, lesion enhancement in the excretory phase in relation to the unenhanced phase, and heterogeneous enhancement pattern helps distinguish RCC from oncocytoma.

Second-generation dual-energy computed tomography of the abdomen: radiation dose comparison with 64- and 128-row single-energy acquisition.

PURPOSE: This study was designed to compare the radiation dose in abdominal dual-energy (DE) and single-energy (SE) acquisitions obtained in clinical practice with a second-generation DE computed tomography (DECT) and to analyze the dose variation in comparison with an SE acquisition performed with a 64-row SECT (SECT). METHODS: A total of 130 patients divided into 2 groups underwent precontrast and portal abdominal 128-row CT examination. In group A, DE portal acquisition was performed using a detector configuration of 2 × 40 × 0.6 mm, tube A at 80 kVp and a reference value of 559 mAs, tube B at 140 kVp and a reference value of 216 mAs, pitch 0.6, and online dose modulation; group B underwent SE portal acquisition using a detector configuration of 64 × 0.6 mm, 120 kVp and a reference value of 180 mAs, pitch 0.75, and online dose modulation. Group C consisted of 32 subjects from group A previously studied with 64-row SECT using the following parameters: detector configuration 64 × 0.6 mm, 120 kVp and a reference value of 180 mAs, pitch 0.75, and online dose modulation. In each group, the portal phase dose-length product and radiation dose (mSv) were calculated and normalized for a typical abdominal acquisition of 40 cm. RESULTS: After normalization to standard 40-cm acquisition, a dose-length product of 599.0 ± 133.5 mGy · cm (range, 367.5 ± 1231.2 mGy · cm) in group A, 525.9 ± 139.2 mGy · cm (range, 215.7-882.8 mGy · cm) in group B, and 515.9 ± 111.3 mGy · cm (range, 305.5-687.2 mGy · cm) in group C was calculated for portal phase acquisition.A significant radiation dose increase (P < 0.05) was observed in group A (10.2 ± 2.3 mSv) compared with group B (8.9 ± 2.4) and group C (8.8 ± 1.9 mSv). No significant difference (P > 0.05) was reported between SE 64- and 128-row acquisitions. A significant positive correlation between radiation dose and body mass index was observed in each group (group A, r = 0.59, P < 0.0001; group B, r = 0.35, P < 0.0001; group C, r = 0.20, P = 0.0098). CONCLUSIONS: In clinical practice, abdominal DECT acquisition shows a significant but minimal radiation dose increase, on the order of 1 mSv, compared with 64- and 128-row SE acquisition. The slightly increased radiation dose can be justified if the additional information obtained using a spectral imaging approach directly impacts on patient management or reduce the overall radiation dose with the generation of virtual unenhanced images, which can replace the precontrast acquisition.

Virtual unenhanced images of the abdomen with second-generation dual-source dual-energy computed tomography: image quality and liver lesion detection.

PURPOSES: We aimed to analyze the image quality, CT number, artifacts, radiation dose reduction, and coverage in abdominal virtual unenhanced (VU) and conventional unenhanced (CU) data sets obtained with a second-generation dual-energy computed tomography and to compare the sensitivity of VU and CU data sets for liver lesion detection. MATERIALS AND METHODS: One hundred eleven patients underwent triphasic abdominal CT examination that included single-energy CU and dual-energy arterial and portal phases. Virtual unenhanced images were generated from arterial (AVU) and portal (PVU) phases. Two abdominal radiologists independently (a) analyzed the image quality using a 5-point scale, CT number, and noise of the abdominal organs and (b) identified and characterized liver lesions in CU, AVU, and PVU. The triphasic abdominal examination was considered the reference standard for liver lesion detection and characterization. RESULTS: The quality of VU images was mostly excellent but not as good as CU images (P < 0.05). The mean (SD) image quality classified by readers 1 and 2 was 4.9 (0.2; range, 4.7-5.0) and 4.8 (0.5; range, 4.4-4.9) for CU, 4.7 (0.4; range, 4.3-4.9) and 4.6 (0.4; range, 4.2-4.8) for AVU, and 4.7 (0.6; range, 4.1-4.8) and 4.6 (0.4; range, 4.2-4.8) for PVU, respectively. The CT number of the liver, the spleen, the pancreas, the renal cortex and medulla, the aorta, and the retroperitoneal fat was higher in AVU and PVU than in CU images. A total of 270 liver lesions were found in 76 patients. Portal virtual unenhanced data set was more sensitive than AVU and CU were for hypodense lesions smaller than 1 cm. Reader 1 correctly detected 72/144 (50.0%), 61/144 (42.4%), and 55/144 (38.2%) hypodense lesions with PVU, AVU, and CU, respectively; and reader 2 correctly diagnosed 70/144 (48.7%), 62/144 (43.0%), and 53/144 (36.8%) lesions with PVU, AVU, and CU, respectively. Conventional unenhanced data set was more sensitive than AVU or PVU was for small calcified lesions. Reader 1 detected 24/40 (60.0%), 24/40 (60.0%), and 40/40 (100%) with PVU, AVU, and CU, respectively; and reader 2 detected 27/40 (67.5%), (25/40) 62.5%, and 40/40 (100%) with PVU, AVU, and CU, respectively. The dose reduction achieved by omitting the unenhanced acquisition was a mean (SD) of 21.1% (1.2%; P < 0.01). CONCLUSIONS: Second-generation abdominal VU data sets, despite a mostly excellent image quality, still cannot replace CU images in clinical practice because of limitations in material subtraction. ADVANCES IN KNOWLEDGE: 1. Second-generation abdominal VU data sets yield excellent image quality but are still slightly lower than that of CU. 2. More small hypodense liver lesions were detected in VU images than in CU images; however, a significant number of small calcified lesions were not identified in VU images. 3. Second-generation abdominal VU images are still not ready to replace CU images in clinical practice. Implications for Patient Care: 1. Using VU images in abdominal studies makes it possible to reduce the total radiation dose delivered to patients who need multiphasic acquisition by avoiding precontrast scan. 2. Erroneous material subtraction and incomplete abdominal coverage represent a limit in VU data set application in clinical routine.

Pathways of lymphatic spread in male urogenital pelvic malignancies.

Regional lymph node involvement in urogenital malignancies (category N in the TNM classification system) is a significant radiologic finding, with important implications for treatment and prognosis. Male urogenital pelvic cancers commonly spread to iliopelvic or retroperitoneal lymph nodes by following pathways of normal lymphatic drainage from the pelvic organs. The most likely pathway of nodal spread (superficial inguinal, pelvic, or paraaortic) depends on the tumor location in the prostate, penis, testis, or bladder and whether surgery or other therapy has disrupted normal lymphatic drainage from the tumor site; knowledge of both factors is needed for accurate disease staging. At present, lymph node status is most often assessed with standard anatomic imaging techniques such as multidetector computed tomography or magnetic resonance (MR) imaging. However, the detection of nodal disease with these techniques is reliant on lymph node size and morphologic characteristics, criteria that provide limited diagnostic specificity. Functional imaging techniques, such as diffusion-weighted MR imaging performed with or without a lymphotropic contrast agent and positron emission tomography, may allow a more accurate nodal assessment based on molecular or physiologic activity.

Solid mature ovarian teratoma with intrarectal protusion: case report.

BACKGROUND: Primary rectal teratoma is a very rare entity. It has been suggested that these tumors grow from aberrant germinal cells of the embryonic digestive tract. Ovarian tumor can also erode the rectal wall, allowing the formation of a fistula localized inside the rectum, becoming an extremely rare complication. CLINICAL CASE: We report the first case of a 54-year old woman with transanal bleeding whose endoscopic investigation showed a hairy-covered tumor in its surface localized 15 cm from the anal margin. Scanning detected its exact location and the presence of bony tissue within. By means of a laparotomy, we identified the left ovary fusioned to the anterior face of the rectum where a 5 x 4 cm tumor was originally protruding towards its lumen. Left oophorectomy was performed and through a peri-tumoral section of the intestinal wall we extracted the tumor from the inner rectum and closed the defect with simple sutures. Histological report demonstrated a conglomerate of tissues that corresponded to the three germinal layers. CONCLUSIONS: Although rare, diagnosis of intrarectal ovarian teratoma must be considered as a differential diagnosis in patients with rectal tumors. Diagnosis is relatively easy in the presence of a tumor with a hairy surface that is evaluated endoscopically. For treatment we suggest a simple procedure with adequate results.

Teratoma sólido maduro de ovario con protrusión intrarrectal: informe de un caso / Solid mature ovarian teratoma with intrarectal protusion: case report

Introducción: El teratoma primario de recto es una entidad extremadamente rara; se ha sugerido que deriva de células germinales aberrantes del tracto digestivo embrionario. Una complicación inusitada es que el tumor ovárico erosione la pared rectal y permita la formación de una fístula para así alojarse en el interior del recto. Caso clínico: Mujer de 54 años de edad con sangrado transanal. Por endoscopia se observó tumor cubierto de pelos en su superficie, localizado a 15 cm del margen anal. Una tomografía computarizada identificó la localización exacta y la presencia de tejido óseo en su interior. Mediante laparotomía se apreció el ovario izquierdo fusionado a la cara anterior del recto, de donde se originaba un tumor de 5 × 4 cm que protruía hacia su luz. Se realizó ooforectomía izquierda y mediante sección peritumoral de la pared intestinal se extrajo el tumor del interior del recto y se cerró el defecto con suturas simples. El estudio histológico demostró conglomeración de tejidos correspondiente a los tres estratos germinales. Conclusiones: Aunque es raro, el diagnóstico de teratoma de ovario intrarrectal debe ser considerado en pacientes con tumores del recto. El diagnóstico es relativamente fácil ante la presencia de pelos en la superficie tumoral, que se evalúa mediante endoscopia.

BACKGROUND: Primary rectal teratoma is a very rare entity. It has been suggested that these tumors grow from aberrant germinal cells of the embryonic digestive tract. Ovarian tumor can also erode the rectal wall, allowing the formation of a fistula localized inside the rectum, becoming an extremely rare complication. CLINICAL CASE: We report the first case of a 54-year old woman with transanal bleeding whose endoscopic investigation showed a hairy-covered tumor in its surface localized 15 cm from the anal margin. Scanning detected its exact location and the presence of bony tissue within. By means of a laparotomy, we identified the left ovary fusioned to the anterior face of the rectum where a 5 x 4 cm tumor was originally protruding towards its lumen. Left oophorectomy was performed and through a peri-tumoral section of the intestinal wall we extracted the tumor from the inner rectum and closed the defect with simple sutures. Histological report demonstrated a conglomerate of tissues that corresponded to the three germinal layers. CONCLUSIONS: Although rare, diagnosis of intrarectal ovarian teratoma must be considered as a differential diagnosis in patients with rectal tumors. Diagnosis is relatively easy in the presence of a tumor with a hairy surface that is evaluated endoscopically. For treatment we suggest a simple procedure with adequate results.