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

OBJECTIVE: To investigate and describe clinical, radiologic and pathologic findings of gastrointestinal stromal tumors. MATERIALS AND METHODS: In the period between December 2000 and March 2006, 16 patients were submitted to surgery for gastrointestinal stromal tumors in our institution. The following variables were taken into consideration: sex and age, signs and symptoms at presentation, tumor site and size, radiological and pathological features, and presence of metastasis. RESULTS: The study population was constituted by nine men and seven women. The primary tumor sites of origin were: stomach (n = 5), rectum (n = 4), small bowel (n = 3), mesentery (n = 3), and colon (n = 1). Mean primary tumor size was 9 cm. Computed tomography was the main radiological method utilized. Circumscribed, lobulated and heterogeneously contrast-enhanced mass was the main image finding. Metastasis was found in nine patients (56% of cases) at presentation or tumor recurrence was observed during the follow-up period (mean = 32 months). CONCLUSION: Gastrointestinal stromal tumor occurs in middle-age adults and the elderly, and must be taken into consideration as differential diagnosis for abdominal masses. Early diagnosis, adequate therapy, and rigorous follow-up are essential, considering the high probability of malignancy of these neoplasms as demonstrated by the present study.

Keywords: Gastrointestinal stromal tumor, Gastrointestinal neoplasms, Gastrointestinal diseases, Sarcoma

OBJECTIVE: To review the clinical and radiographic findings in patients with histologically confirmed Ewing's sarcoma. MATERIALS AND METHODS: Clinical and radiological (whenever available) data of 226 patients with Ewing's sarcoma of the bone were analyzed. RESULTS: Of the evaluated cases, 61.5% (139) were male and 83.7% (189) were white. The average age was 14 years old and the most common site of the lesions was the iliac bone, seen in 13.7% (31) of the cases. The most common radiological findings were lytic lesion with periosteal reaction, seen in 32.7% (74) of the patients. CONCLUSION: Ewing's sarcoma of bone is an aggressive neoplasm, occurring mainly in the second decade of life, which main radiological findings are lytic lesions with periosteal reaction, typical characteristic of aggressive lesions.

Keywords: Conventional radiology, Ewing's sarcoma, Bone neoplasms

We report the case of a 23-year-old female patient with a low-grade fibromyxoid sarcoma involving the chest wall. The chest radiography and computed tomography scan showed a heterogeneous mass in the lower right hemithorax, with necrosis and calcification foci. Histological examination was suggestive of a leiomyoma but the immunohistochemical study proved to be a low-grade fibromyxoid sarcoma. The clinical outcome of this patient was good, although the computed tomography scan showed signs of malignancy.

Keywords: Computed tomography, Chest wall, Fibromyxoid sarcoma

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

The authors report a case of a 24 year-old female patient with a three-month history of pain and enlargement of the left halux. Ultrasound showed a heterogeneous, hypoechoic solid soft tissue mass with cystic areas and calcification in the dorsum of the left halux. A tendinous structure was identified within the lesion but no evidence of involvement of adjacent osseous structures was found. Doppler ultrasound revealed central and peripheral hypervascularization of the lesion. Magnetic resonance imaging demonstrated a solid soft tissue mass containing a tendinous structure. The lesion appeared as an intermediate signal intensity structure on T1 images, high signal intensity on T2 images, and showed marked enhancement after intravenous administration of gadolinium. No osseous lesions were identified. The patient was submitted to surgical resection of the lesion in the dorsum of the left halux and the pathology results revealed a monophasic fibrous synovial sarcoma.

Keywords: Synovial sarcomas, Soft-tissue tumors, Ultra-sonography, Magnetic resonance imaging

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.

OBJECTIVE: To evaluate the efficacy of percutaneous computed tomography (CT)-guided core needle biopsy of softtissue tumors in obtaining appropriate samples for histological analysis, and compare its diagnosis with the results of the surgical pathology as available. MATERIALS AND METHODS: The authors reviewed medical records, imaging and histological reports of 262 patients with soft-tissue tumors submitted to CT-guided core needle biopsy in an oncologic reference center between 2003 and 2009. RESULTS: Appropriate samples were obtained in 215 (82.1%) out of the 262 patients. The most prevalent tumors were sarcomas (38.6%), metastatic carcinomas (28.8%), benign mesenchymal tumors (20.5%) and lymphomas (9.3%). Histological grading was feasible in 92.8% of sarcoma patients, with the majority of them (77.9%) being classified as high grade tumors. Out of the total sample, 116 patients (44.3%) underwent surgical excision and diagnosis confirmation. Core biopsy demonstrated 94.6% accuracy in the identification of sarcomas, with 96.4% sensitivity and 89.5% specificity. A significant intermethod agreement about histological grading was observed between core biopsy and surgical resection (p < 0.001; kappa = 0.75). CONCLUSION: CT-guided core needle biopsy demonstrated a high diagnostic accuracy in the evaluation of soft tissue tumors as well as in the histological grading of sarcomas, allowing an appropriate therapeutic planning.

Keywords: Sarcoma; Needle biopsy; Computed tomography.

The effective evaluation for the treatment of patients with Ewing tumors depends on the accuracy in the determination of the primary tumor extent and the presence of metastatic disease. Currently, no universally accepted staging system is available to assess Ewing tumors. The present study aimed at discussing the use of PET/CT as a tool for staging, restaging and assessment of therapeutic response in patients with Ewing tumors. In spite of some limitations of PET/CT as compared with anatomical imaging methods, its relevance in the assessment of these patients is related to the capacity of the method to provide further physiological information, which often generates important clinical implications. Currently, the assessment of patients with Ewing tumor should comprise a study with PET/CT combined with other anatomical imaging modalities, such as radiography, computed tomography and magnetic resonance imaging.

Keywords: Ewing sarcoma; Imaging diagnosis; Diagnosis; Evaluation.