Congenital mediastinal cysts are uncommon benign lesions generally caused by an abnormal embryological development of the foregut or coelomic cavity. They are expansive lesions, frequently asymptomatic that may manifest as a result from compression of adjacent structures. Bronchogenic, pericardial, enteric, thymic, esophageal duplication cysts and lymphangiomas are the main entities in this group of lesions. Congenital mediastinal cysts morphology is typical and imaging methods allow a correct diagnosis in a great number of cases. Surgical treatment is indicated only in cases of symptomatic lesions, considering that these lesions present no potential for malignant degeneration. The present study was aimed at commenting and illustrating the most relevant imaging findings of these lesions based on a retrospective review of ten cases collected in the records of the involved institutions.

Keywords: Congenital mediastinal cysts, Cystic neoplasms, Cysts

The present study reports the case of a 51-year-old woman with chest pain, dyspnea and upper chest vessels engorgement, with no clinical evidence of granulomatous disease. Chest imaging study revealed a mediastinal mass with calcifications that was approached by mediastinoscopy with biopsy. Histopathological study demonstrated an etiologically undefined chronic inflammatory pattern compatible with fibrosing mediastinitis.

Keywords: Fibrosing mediastinitis, Mediastinal mass, Fibrosis, Chest radiology

The nasopharynx is located in the upper aerodigestive tract. Its roof is formed by the basisphenoid, basiocciput and the anterior aspect of the first two cervical vertebrae, in front of the clivus. The lateral walls are formed by the margins of the superior constrictor muscle and the pharyngobasilar fascia, pharyngeal recess, torus tubarius and pharyngeal opening of auditory tube. The inferior margin of the nasopharynx is a horizontal plane passing through the hard palate and palatopharyngeal muscle. Anteriorly, it is in direct continuity with the nasal cavity through the posterior choanae. It is approximately 2.0 cm in anteroposterior diameter and about 4.0 cm in craniocaudal extent. Squamous cell carcinoma accounts for about 70% to 98% of nasopharyngeal malignant lesions found in adults. This tumor presents a high incidence in Asians, most frequently in men, and is the third most frequent cancer in women. The clinical presentation of this disease depends on the size and site of the lesion, with small-sized lesions being asymptomatic. Computed tomography and magnetic resonance imaging play essential and complementary roles in the staging and treatment of patients with nasopharyngeal cancer.

Keywords: Computed tomography, Nasopharynx, Tumor, Carcinoma

OBJECTIVE: To distinguish healthy from pathological tissues in pediatric patients with posterior cranial fossa tumors using calculated textural parameters from magnetic resonance images. MATERIALS AND METHODS: We evaluated 14 pediatric patients with posterior cranial fossa tumors using the software MaZda to define the texture parameters in selected regions of interest representing healthy and pathological tissues based on T2-weighted magnetic resonance images. RESULTS: There was a statistically significant difference between normal and tumoral tissues as well as between supposedly normal tissues adjacent and distant from the tumoral lesion. CONCLUSION: Magnetic resonance textural evaluation is an useful tool for determining differences among various tissues, including tissues that appear apparently normal on visual analysis.

Keywords: Magnetic resonance imaging, Textural evaluation, Posterior cranial fossa tumors, Pediatric patients, MaZda software

The authors report a case of a two year-old girl with an extrarenal Wilms' tumor in the retroperitoneum. Abdominal plain films, intravenous urography, abdominal ultrasound and computed tomography examinations showed a retroperitoneal mass adjacent to the right kidney. The patient underwent surgery with complete resection of the mass. The diagnosis of Wilms' tumor was confirmed by histopathological study. Extrarenal Wilms' tumor is an extremely rare malignancy which is almost always presented in medical literature as a case report. The tumor may arise in the retroperitoneum, uterus and ovaries, inguinal groove, testes, skin, and even in the thorax. The exact mechanism of occurrence of this tumor in extrarenal tissues has not yet been established. The diagnosis relies on histopathological study, generally after surgical intervention.

Keywords: Extrarenal Wilms' tumor, Retroperitoneum, Radiology

Traumatic mediastinal lesions are unusual findings in patients with thoracic trauma but may represent poor prognosis and be associated with severe lesions. Mediastinal trauma is increasingly being diagnosed by computed tomography due to the fast acquisition times of helical techniques, allowing the evaluation of critically ill patients and the adoption of efficient therapeutic measures. The authors studied 11 patients with mediastinal lesions who were submitted to computed tomography due to thoracic trauma. The most frequent finding was mediastinal bleeding characterized by infiltration of mediastinal fat, dense material within the mediastinal spaces or hematoma. Hemopericardium was the second most common lesion in this series, appearing as dense or liquid material in the pericardium. Aortic lesions such as wall irregularities or pseudoaneurisms were less commonly seen (three patients). In this study blunt thoracic traumas were observed in six cases whereas penetrating trauma occurred in five cases. The causes of blunt trauma were pedestrians struck by car, motor vehicle accidents and falls. Penetrating trauma was due to lesions produced by bullets or knifes.

Keywords: Mediastinal bleeding, Aortic lesion, Computed tomography

The authors report a case of intraabdominal desmoplastic small round cell tumor in a 21-year-old male patient who presented with abdominal pain, right lower limb thrombosis and obstructive loss of renal function. Initial investigation showed a large lobulated intraabdominal soft tissue mass with internal cystic cavities, located posteriorly to the bladder and causing obstruction of ureteral flow, compression of the right iliac vein and partial occlusion of the rectum. Involvement of intraperitoneal and retroperitoneal nodes was also seen. Ultrasound, computed tomography and magnetic resonance imaging findings, as well as surgical and histopathology macroscopical, microscopical and immunohistochemistry findings are described.

Keywords: Desmoplastic small cell tumor, Desmoplastic tumor

Undifferentiated embryonal sarcoma of the liver is a rare disease that affects predominantly children over five years of age. The most common macroscopic finding is a large hepatic mass with a greater solid component and smaller cystic areas. However, computed tomography tends to overestimate the cystic components of the lesion and consequently ultrasonography is considered a more reliable technique for evaluating the texture of the tumor. Imaging methods can help to rule out nonneoplastic diseases such as liver abscesses and hematomas, and to establish the extent of the lesions. The diagnosis of undifferentiated embryonal sarcoma can be correctly inferred when imaging findings, the age of the patient and serum alpha protein levels are concurrently analyzed. The authors report a case of undifferentiated embryonal sarcoma in a 10-year-old girl and discuss the imaging findings features and differential diagnosis.

Keywords: Sarcoma, Tumor, Liver

The authors report a case of a 40-year-old male patient with sickle cell disease who presented with intra-thoracic extramedullary hematopoiesis and paravertebral expansive lesions that appeared as soft tissue density masses on conventional x-ray films. A computed tomography of the chest demonstrated soft tissue density masses in the lower third of the paravertebral spaces. These masses presented well-defined limits, lobulated edges and were heterogeneous due to areas of interposed adipose and soft density tissues. The lung parenchyma had no abnormalities. Computed tomography of the abdomen revealed diffuse hiperdensity and enlargement of the liver that was attributed to hemosiderosis, and an atrophic and calcified spleen due to repeated episodes of infarction.

Keywords: Intrathoracic extramedullary hematopoiesis. Computed tomography. Sickle cell anemia. Posterior mediastinum.

The literature reports only rare cases of urinary ascites, usually secondary to rupture of the bladder and not to renal calyx rupture. The present report describes an uncommon case of posterior urethral valve in a newborn with ascites caused by the rupture of a renal calyx that, to our knowledge, was diagnosed for the first time by ultrasonography.

Keywords: Newborn; Urinary ascites; Renal calyx rupture; Posterior urethral valve; Ultrasonography.

The authors report a rare case of granular cell tumor in the left medial rectus muscle of a seven-year-old boy. Clinical, pathologic and radiologic findings of the present case are described and a brief literature review is undertaken.

Keywords: Orbit; Granular cell tumor.

Disc herniation with posterior epidural migration is a rare and often symptomatic entity. Multiple are the natural barriers that prevent this pattern of migration. Enhanced magnetic resonance imaging is the diagnostic modality of choice in these cases. The diagnostic dilemma in this case was the contraindication to the use of contrast since the patient was known to have chronic renal failure.

Keywords: Lumbar hernia; Complication; Epidural space; Posterior; Magnetic resonance imaging; Contrast.

Inflammatory myofibroblastic tumors rarely affect the urinary tract or children, and frequently mimic malignancy on imaging studies. According to the recent literature, only 35 cases of such bladder tumors in children have been reported. The authors present the case of a child with a bladder myofibroblastic tumor with favorable progression following complete surgical resection.

Keywords: Bladder tumor; Inflammatory myofibroblastic tumor; Computed tomography.

We report an unprecedented case of ectopic thymoma in a young adult. A 33-year-old male presented with a 10-day history of non-productive cough and fever. Investigation revealed mediastinal widening without pulmonary involvement. Computed tomography showed a large mass—14.8 × 10.8 × 8.4 cm—in the mid-posterior mediastinum, and a biopsy obtained by video-assisted thoracoscopy indicated that the mass was a tumor. Immunohistochemistry showed combined thymoma type AB1. Because of the considerable proportions of the tumor and its close proximity to major structures, the patient was treated with chemotherapy.

Keywords: Thymoma; Middle mediastinum; Posterior mediastinum; Ectopic tumor.

OBJECTIVE: We aimed to evaluate whether human immunodeficiency virus (HIV)-positive patients with and without clinically significant memory deficits and healthy control participants differ on in vivo hydrogen-1 magnetic resonance spectroscopy (H-MRS) in the posterior cingulate gyri. MATERIALS AND METHODS: In total, 21 HIV-positive patients with memory deficit (HIV+wMD) were compared with 15 HIV-positive patients without memory deficit (HIV+wOMD) and 22 sex-, age-, and education-matched control participants. Memory impairments were classified based on the participants’ performance on the Rey Auditory Verbal Learning Test. Short echo time (30 ms), single-voxel H-MRS was performed using a 1.5-T magnetic resonance scanner. RESULTS: The HIV+wMD and HIV+wOMD groups had higher choline/creatine ratio in the posterior cingulate gyri than the control group. There were no significant metabolite ratio differences between the HIV+wMD and HIV+wOMD groups. CONCLUSION: HIV-positive patients with and without memory deficits had significantly higher choline/creatine ratios than controls in the posterior cingulate gyri, which may reflect cerebral inflammation, altered cell membrane metabolism, microgliosis, and/or astrocytosis.

Keywords: HIV; Memory deficit; Posterior cingulate gyrus; Magnetic resonance spectroscopy.