Objective There is little literature regarding imaging features of alveolar soft-part sarcoma. We performed a comprehensive assessment of imaging characteristics of this rare tumor to determine if there are features that suggest the diagnosis. Materials and Methods Twenty-two subjects with alveolar soft-part sarcoma underwent pre-therapy imaging (16 MRIs, 3 CTs, 3 both) as part of enrollment on Children's Oncology Group protocol ARST0332 for treatment of non-rhabdomyosarcoma soft-tissue sarcomas. Two radiologists retrospectively reviewed imaging by consensus and recorded tumor location, size, contour, internal architecture, signal characteristics, presence of flow-voids and enhancement patterns. Results The 12 females and 10 males ranged in age from 8 to 23.6 years (mean, 15.7 years). The most common anatomic site was lower extremity (12/22, 55%) followed by upper extremity (4/22, 18%). Maximal tumor diameter ranged from 2.3 cm to 20.0 cm (median, 5.9 cm). All tumors imaged with MRI had flow-voids (19/19, 100%) and 19 (19/22, 86%) had large peripheral vessels, lobulated margins and nodular internal architecture. T1W pre-contrast MR imaging was available for 18 tumors; 14 (14/18, 78%) appeared slightly hyperintense to muscle. Of 16 imaged with contrast, 11 (11/16, 69%) showed intense and 5 (5/16, 31%) moderate enhancement. Six (6/16, 38%) had thick enhancing peripheral rims with non-enhancing centers consistent with necrosis. Conclusions Imaging features of alveolar soft part sarcoma include flow voids, large peripheral vessels, internal nodularity and lobulated margins. Contrast administration produces intense to moderate enhancement, sometimes with a thick enhancing peripheral rim around central necrosis. Extremity tumors with these imaging features in a child or young adult should suggest the diagnosis of alveolar soft part sarcoma.

Although not common, late-presenting CDH can result in confusing plain film radiographic findings and a delay in diagnosis. We found that the most important finding in analyzing these radiographs is in evaluating the location and position of the gastric bubble with the more common left-side hernias.

SUMMARY:A 68-year-old man presented with a highly symptomatic brain stem tumor originally thought to be a brain stem glioma. Intraoperative MR imaging guidance was used to resect the tumor, and real-time evoked potentials improved during surgery. Pathology findings unexpectedly indicated that the tumor was an intra-axial brain stem schwannoma, a condition reported, to our knowledge, only 6 times previously in the literature. The patient made an excellent recovery with reversal of his symptoms. We report an unusual case of a highly symptomatic intra-axial schwannoma that was successfully treated surgically. Case ReportA 68-year-old man developed gait imbalance, coughing, and hiccups during a 2-month period. The symptoms progressed, and he developed nausea, vomiting, intermittent diplopia, and weakness in his right arm.Physical examination revealed an alert well-oriented patient, with normally reacting pupils and intact extraocular movements. Positive findings included bilateral nystagmus on lateral gaze, right facial weakness, hoarse voice, and weakness in the right upper and lower extremity (4 of 5 weaknesses on the 5-point strength scale). Swallowing and motor speech assessment showed severe pharyngeal phase dysphagia with noneffective and unsafe swallowing.MR imaging showed a cystic septate lesion involving the midbrain, pons, and medulla (Fig 1). The upper extent was in the left midbrain in the anterior pretectal region. The inferior extent was from the left medulla up to the anterior pyramids. The lesion was hypointense on T1 (not shown), hyperintense on T2 (Fig 2), and had enhancing septa on gadolinium-enhanced images (Fig 1). The cerebellar peduncles and anterior cerebellum on the left were also involved, showing fluid-attenuated inversion recovery signal-intensity abnormality (not shown).The patient underwent a craniotomy with intraoperative MR imaging and sonography, with microscopic dissection guided by motorevoked potentials. The surface of the brain stem where the tumor came to the surface was abnormal, but there was no extension along any cranial nerve. A biopsy showed a pure spindle cell tumor. Pathologic considerations at the time were either meningioma, schwannoma, or tanycytic ependymoma. There were no mitotic figures. Xanthochromic intratumoral cyst fluid was found to be under moderate pressure. The tumor was resected but had to be coagulated medially and inferiorly at the brain stem attachment where dissection was difficult. Multiple septa were fenestrated and resected. Right-sided evoked potentials returned immediately once the cyst was decompressed. A gross total resection was achieved.Pathologic results after the surgery showed a spindle cell neoplasm. Additional special studies were performed on permanent tissue. A positive tumor reactivity was seen in tumor cells with S-100, but they were negative for glial fibrillary acidic protein and epithelial membrane antigen. Studies for MIB-1 showed rare labeled tumor nuclei. A diagnosis of schwannoma was made. The patient's neurologic status improv...

A 38-year-old man presented with a highly symptomatic lumbar intradural extramedullary tumor. MRI features strongly suggested a myxopapillary ependymoma, with a possible drop metastasis. No filum terminale or spinal-cord attachment to the tumor was seen intraoperatively. Histopathology, surprisingly, indicated a malignant round-cell tumor, strongly CD 99-positive, and FISH indicated a rearranged ESWR1 locus. A diagnosis of Ewing tumor (ET) was made. Only eight cases in the lumbar region have been previously reported.

A case is reported in which a 46-year-old normotensive male patient presented with large right-sided painless abdominal mass. On sonography there was a large cyst in the lower pole of right kidney. Intravenous urography showed distortion of pelvicollecting system and medial shift of upper right ureter. Exploration revealed a cystic mass (18 x 15 cm) located in lower pole of right kidney. It contained brownish fluid and because of suspicion of malignancy radical nephrectomy was carried out. Histological examination showed the cystic mass to be adrenal tissue infiltrated by neoplastic cells. Characteristic organoid nests of malignant cells ("Zellaballen" were present. Cells stained positively for chromogranin, neurone specific enolase (NSE), neurofilament, and synaptophysin. Sustentacular cells showed positive reaction to S-100 protein. No further treatment was offered. Patient remains well at 30 months follow-up. On medline search there is record of three cases of intra-renal paraganglioma in English literature and the present case appears to be the fourth one.