Evaluation of ctDNA in the Prediction of Response to Neoadjuvant Therapy and Prognosis in Locally Advanced Rectal Cancer Patients: A Prospective Study.

"Watch and wait" is becoming a common treatment option for patients with locally advanced rectal cancer (LARC) submitted to neoadjuvant treatment. However, currently, no clinical modality has an acceptable accuracy for predicting pathological complete response (pCR). The aim of this study was to assess the clinical utility of circulating tumor DNA (ctDNA) in predicting the response and prognosis in these patients. We prospectively enrolled a cohort of three Iberian centers between January 2020 and December 2021 and performed an analysis on the association of ctDNA with the main response outcomes and disease-free survival (DFS). The rate of pCR in the total sample was 15.3%. A total of 24 plasma samples from 18 patients were analyzed by next-generation sequencing. At baseline, mutations were detected in 38.9%, with the most common being TP53 and KRAS. Combination of either positive magnetic resonance imaging (MRI) extramural venous invasion (mrEMVI) and ctDNA increased the risk of poor response (p = 0.021). Also, patients with two mutations vs. those with fewer than two mutations had a worse DFS (p = 0.005). Although these results should be read carefully due to sample size, this study suggests that baseline ctDNA combined with mrEMVI could potentially help to predict the response and baseline ctDNA number of mutations might allow the discrimination of groups with different DFS. Further studies are needed to clarify the role of ctDNA as an independent tool in the selection and management of LARC patients.

Ovarian clear cell carcinoma arising in a large endometrioma - A case report with pathological correlation and literature review.

Endometriosis-associated ovarian cancer represents the most common form of malignancy associated with this benign disease. It has a better prognosis than most types of ovarian cancer, with endometrioid adenocarcinoma and clear cell carcinoma as the main histological types. Clinical presentation is usually nonspecific and tumor biomarkers can be misleading, since they can also be elevated in the presence of benign ovarian endometriosis. We report a case of a 52-year-old woman with known ovarian and deep pelvic endometriosis, who developed ovarian clear cell carcinoma within a large endometrioma. The imaging findings highlight the key role of magnetic resonance imaging in detecting suspicious features such as loss of the "T2 shading" sign, loss of high T1 signal of an endometrioma, or the presence of mural nodules. Early detection of these malignancies is fundamental for adequate surgical treatment and overall outcome.

Pitfalls of diffusion-weighted imaging of the female pelvis.

Diffusion-weighted imaging (DWI) is widely used in protocols for magnetic resonance imaging (MRI) of the female pelvis. It provides functional and structural information about biological tissues, without the use of ionizing radiation or intravenous administration of contrast medium. High signal intensity on DWI with simultaneous low signal intensity on apparent diffusion coefficient maps is usually associated with malignancy. However, that pattern can also be seen in many benign lesions, a fact that should be recognized by radiologists. Correlating DWI findings with those of conventional (T1- and T2-weighted) MRI sequences and those of contrast-enhanced MRI sequences is mandatory in order to avoid potential pitfalls. The aim of this review article is the description of the most relevant physiological and benign pathological conditions of the female pelvis that can show restricted diffusion on DWI.

Pitfalls of diffusion-weighted imaging of the female pelvis / Armadilhas em imagem ponderada em difusão da pelve feminina

Abstract Diffusion-weighted imaging (DWI) is widely used in protocols for magnetic resonance imaging (MRI) of the female pelvis. It provides functional and structural information about biological tissues, without the use of ionizing radiation or intravenous administration of contrast medium. High signal intensity on DWI with simultaneous low signal intensity on apparent diffusion coefficient maps is usually associated with malignancy. However, that pattern can also be seen in many benign lesions, a fact that should be recognized by radiologists. Correlating DWI findings with those of conventional (T1- and T2-weighted) MRI sequences and those of contrast-enhanced MRI sequences is mandatory in order to avoid potential pitfalls. The aim of this review article is the description of the most relevant physiological and benign pathological conditions of the female pelvis that can show restricted diffusion on DWI.

Resumo A imagem ponderada em difusão (IPD) é amplamente utilizada em protocolos de ressonância magnética (RM) da pelve feminina. Fornece informações funcionais e estruturais de tecidos biológicos sem uso de radiação ionizante ou de administração intravenosa de material de contraste. Hipersinal em IPD com hipossinal simultâneo em mapas de coeficiente de difusão aparente geralmente está associada a malignidade. No entanto, esse padrão também pode ser visto em muitas lesões benignas, um fato que deve ser reconhecido por radiologistas. É imprescindível fazer a correlação dos achados de IPD com os de sequências de RM convencionais (em T1 e T2) e daquelas com contraste para evitar possíveis armadilhas. O objetivo deste artigo de revisão é descrever as condições fisiológicas e patológicas benignas mais relevantes da pelve feminina que podem demonstrar restrição à difusão da água em IPD.

Obturator hernia: a rare cause of bowel obstruction.

An obturator hernia is a rare condition and an unusual cause of intestinal obstruction. With a challenging diagnosis, it has one of the highest mortality rates of all abdominal wall hernias. The authors present a case of an elderly woman with bowel obstruction secondary to an incarcerated obturator hernia. An 80-year-old woman presented at the emergency room with complaints for the last 2 days of nausea, vomiting, constipation and lower right abdominal pain that radiated down to the right medial thigh. Abdominal tenderness to deep palpation of the right iliac fossa and mildly distention were noted. A CT scan demonstrated bowel obstruction secondary to an incarcerated obturator hernia. The patient underwent emergency exploratory laparotomy. The incarcerated bowel was reduced and the defect was repaired with a plug of polypropylene mesh covered with peritoneum. The patient had an uneventful postoperative period and was discharged on the fifth postoperative day.

Endometrial Tuberculosis Simulating an Ovarian Cancer: a case report.

Female genital tuberculosis remains a major health problem in developing countries and is an important cause of infertility. As symptoms, laboratory data and physical findings are non-specific, its diagnosis can be difficult. We describe a case of a 39-year-old woman suffering from peri-umbilical pain and increased abdominal size for one year, anorexia, asthenia, weight loss, occasionally dysuria and dyspareunia, and four months amenorrhea. Laboratory data revealed cancer antigen 125 (CA-125) level of 132.3 U/mL, erythrocyte sedimentation rate of 42 mm/h, and gamma-globulins of 2.66 g/dL. Computed tomography scan showed loculated ascites. It was initially suspected a carcinomatous origin, but ascites evaluation was negative for malignant cells. Magnetic resonance imaging from another hospital showed endometrial heterogeneity. Therefore, an endometrial biopsy was performed demonstrating an inflammatory infiltrate with giant cells of type Langhans and bacteriological culture identified Mycobacterium tuberculosis.

A tuberculose genital feminina continua a representar uma patologia importante nos países em desenvolvimento e constitui uma causa importante de infertilidade. Os seus sintomas, achados laboratoriais e exame físico não são específicos, tornando difícil o seu dia-gnóstico. Descrevemos o caso de uma doente do sexo feminino, de 39 anos, com dor peri-umbilical e aumento do volume abdominal desde há um ano, anorexia, astenia, perda ponderal, ocasionalmente disúria e dispareunia, assim como amenorreia desde há quatro meses. Os dados laboratoriais mostraram valores de 132,3 U/mL do marcador tumoral CA-125, 42 mm/h de velocidade de sedimentação e 2,66 g/dL de gama-globulinas. A tomografia computadorizada mostrou ascite loculada. Inicialmente suspeitou-se de etiologia maligna, mas o exame citológico do líquido ascítico foi negativo para células malignas. Foi efectuada ressonância magnética pélvica, noutra instituição, que revelou heterogeneidade do endométrio. Foi então realizada biópsia endometrial que revelou um infiltrado inflamatório com células gigantes de Langhans e o exame bacteriológico isolou Mycobacterium tuberculosis.