Giant cell tumor is the sixth most frequent primary bone neoplasm, affecting long bone metaphysis, most frequently in young adults. On radiological images, this tumor appears as a lytic, well-defined, eccentric lesion. The authors report a case of benign giant cell tumor in a patient who presented with lung metastases five years after undergoing resection of the primary tumor.

Keywords: Giant cell tumor, Benign, Metastasis

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

We present a case of a 27-year-old male patient submitted to computed tomography and magnetic resonance imaging for the evaluation of a renal tumor. The radiological features of the mass suggested the diagnosis of a malignant renal tumor of parenchymatous origin. However, the histological findings proved to be a benign solitary fibrous tumor within the pelvis and caliceal portion of the right kidney.

Keywords: Neoplasia, Fibrous tumor, Kidney, Mesothelioma, Computed tomography, Magnetic resonance imaging

The authors report a case of a patient with a progressive-growing mass in the left subaxillary region, since childhood. Chest x-ray and computed tomography showed a well-defined low attenuation mass with irregular calcifications contiguous with the left fifth rib. Histological findings were consistent with parosteal lipoma, a rare slow-growing benign tumor.

Keywords: Parosteal lipoma, Rib, Soft tissue tumor

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

Ewing's sarcoma and Triton's tumor are two uncommon bone tumors of the skull that have nonspecific clinical and imaging features. However, imaging methods are important in the detection of the lesions during the diagnostic investigation in order to evaluate the extent of the bone lesions, involvement of soft tissues and brain, and to determine the presence of local recurrence and metastases. The confirmatory diagnosis relies on histological studies and immunohistochemistry. The authors report two cases of patients with these tumors and present the radiological findings.

Keywords: Ewing's sarcoma, Triton's tumor, Bone tumors, Skull, 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 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.

OBJECTIVE: To estimate extracranial doses on eyes, thyroid, chest and pelvis in patients submitted to radiosurgery with 6 MV linear accelerator. MATERIALS AND METHODS: The present study evaluated 11 patients, 7 of them with primary, and 4 with secondary brain tumors. In the latter group, 2 patients had two lesions. Thermoluminescent dosimeters were utilized to estimate the extracranial dose. Radiosurgery cones ranges between 1.50 and 3.75 cm and doses between 1300 and 2000 cGy. RESULTS: Mean patients' age was 52 years, and 63.6% of them were women and 36.4%, men. Lesion locations were the following: right acoustic nerve (1), frontal (2), parietal (5), right occipital (1), cerebellum (2) and parasagittal (2). Mean received doses were the following: 5.1 cGy between the eyes; 4.8 cGy in the right eye; 6.5 cGy in the left eye; 4.2 cGy in the thyroid; 1.65 cGy in the chest; and 0.45 cGy in the pelvis. CONCLUSION: The results demonstrate that that although the eye doses do not exceed the tolerance limits for occurrence of lens opacity, it is important that the risks associated with radiation doses are taken into consideration by radiotherapists in the planning of cranial radiosurgery procedures.

Keywords: Brain tumor; Radiotherapy; Radiosurgery; Dosimetry.

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.

A congenital ranula is a rare cystic malformation seen in the oral cavity. This pseudocyst is normally located in the sublingual space between the mylohyoid muscle and the lingual mucosa. A 24-year-old woman, gravida 3, para 2, at 29 weeks' gestation was referred to our institution because of polihydramnios and large oral mass.

Keywords: Prenatal diagnosis; Ultrasound; Oral tumor; Ranula.

OBJECTIVE: To evaluate the accuracy of computed tomography for local and lymph node staging of Wilms' tumor. MATERIALS AND METHODS: Each case of Wilms' tumor was evaluated for the presence of abdominal lymph nodes by a radiologist. Signs of capsule and adjacent organ invasion were analyzed. Surgical and histopathological results were taken as the gold standard. RESULTS: Sensitivity was 100% for both mesenteric and retroperitoneal lymph nodes detection, and specificity was, respectively, 12% and 33%, with positive predictive value of 8% and 11% and negative predictive value of 100%. Signs of capsular invasion presented sensitivity of 87%, specificity of 77%, positive predictive value of 63% and negative predictive value of 93%. Signs of adjacent organ invasion presented sensitivity of 100%, specificity of 78%, positive predictive value of 37% and negative predictive value of 100%. CONCLUSION: Computed tomography tumor showed low specificity and low positive predictive value in the detection of lymph node dissemination. The absence of detectable lymph nodes makes their presence unlikely, and likewise regarding the evaluation of local behavior of tumors.

Keywords: Computed tomography; Wilms' tumor; Staging.

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: To review the imaging features of granular cell tumors of the breast (on mammography, ultrasound, and magnetic resonance imaging), establishing a pathological correlation, in order to familiarize radiologists with this entity and make them aware of the differential diagnoses, other than malignancy, of lesions with spiculated margins. MATERIALS AND METHODS: We reviewed the medical records (from a clinical-pathology database and picture archiving and communication system) of five patients with a pathologically confirmed diagnosis of granular cell tumor of the breast, treated at the Portuguese Oncology Institute of Lisbon, in the city of Lisbon, Portugal, between January 2012 and December 2018. RESULTS: All five tumors exhibited imaging features highly suggestive of malignancy (BI-RADS 5 lesions), namely spiculated margins, significant depth, and posterior acoustic shadowing (on ultrasound). One tumor showed a kinetic curve indicative of washout on magnetic resonance imaging, two were adherent to the pectoralis muscle, and one was accompanied by skin retraction. Pathology provided the definitive diagnosis in all cases. CONCLUSION: Granular cell tumors of the breast pose a diagnostic challenge because they can present with clinical and imaging features mimicking malignancy, and the diagnosis is therefore provided by pathology. Radiologists should be familiarized with this entity, so they can be aware of the fact that breast lesions with spiculated margins can be indicative of diagnoses other than malignancy.

Keywords: Granular cell tumor; Breast neoplasms; Schwann cells.