Foci of decreased signal on T2-weighted MR images in leiomyosarcomas of soft tissue: correlation between MR and histological findings

OBJECTIVE: Leiomyosarcomas are rare soft tissue sarcomas with varying MR signal characteristics and histologic pictures. The purpose of this study was to investigate the histological features of foci, which showed decreased signal on T2-weighted images in leiomyosarcomas of soft tissue. MATERIAL AND METHODS: We reviewed the MR images of six histologically proved cases of leiomyosarcomas of soft tissue and correlated the foci, which showed decreased signal on T2-weighted images with the histologic findings. RESULT: Microscopic examination revealed that these foci were composed of hyalinization of neoplastic tissue, internal septations, deposition of hemosiderin, or corresponded to metaplastic bone. CONCLUSION: The authors explain that the foci of decreased signal on T2-weighted MR images correspond to tissue components of the lesion, particularly fibrous tissue, hemosiderin and metaplastic bone. So, the suggestion is that leiomyosarcoma should be considered in the differential diagnosis of soft-tissue tumors that show foci of decreased signal on T2-weighted MR images.     

Soft-tissue myoepithelioma of the hypothenar region: a case report

Myoepithelial tumors only recently have been recognized as occurring primarily in soft tissue, and only a few cases have been described in the literature. The occurrence of these tumors in the hand is even more limited. In this article, we review the clinical, radiologic, and histologic features of a benign myoepithelioma of the hypothenar region of the left hand.     

Primary hepatic gastrinoma: Report of a case and review of literature

Primary hepatic gastrinoma is a very rare ectopic gastrinoma with less than 20 cases reported worldwide. We report the case of a patient with hypergastrinemia who was subjected to exhaustive preoperative and intraoperative imaging and also careful surgical exploration of the duodenum and pancreas which failed initially to identify the primary tumour. Eventually the patient was subjected to left liver lobectomy,as a small palpable lesion was noted intraoperatively. The diagnosis of gastrinoma requires a high index of clinical suspicion and the flawless cooperation of many specialties.     

The value of magnetic resonance arthrography of the temporomandibular joint in imaging disc adhesions and perforations

Objectives

This study attempted to validate MR arthrography (MRAr) of the temporomandibular joint (TMJ) in detecting the position, integrity and relations of the articular disc and retrodiscal tissue.

Methods

A total of 20 TMJs from 10 patients with severe TMJ dysfunction underwent MRI and MRAr. A paramagnetic contrast medium was injected into the upper joint compartment to observe possible adhesions and/or leakage into the lower compartment. 15 TMJs were surgically or arthroscopically explored and restored.

Results

MRAr was approximately in the same diagnostic value as MRI when locating position, but superior in detecting disc perforations (eight TMJs) and adhesions (seven TMJs) appearing together in four cases. Surgery confirmed radiological findings in all but one case, where arthroscopy and surgery failed to confirm a disc perforation indicated by MRAr.

Conclusions

TMJ MRAr may simultaneously reveal adhesions and perforations. Sensitivity and the probability of false-positive results require further study.     

CT of hemodynamically unstable abdominal trauma

This article is an appraisal of the use of CT in the management of patients with unstable abdominal trauma. We examined 41 patients with abdominal trauma using noncontrast dynamic CT. In 17 patients a postcontrast dynamic CT was also carried out. On CT, 25 patients had hemoperitoneum. Thirteen patients had splenic, 12 hepatic, 6 pancreatic, 8 bowel and mesenteric, 12 renal and 2 vascular injuries. Seven patients had retroperitoneal and 2 patients adrenal hematomas. All but five lesions (three renal, one pancreatic, and one splenic) were hypodense when CT was performed earlier than 8 h following the injury. Postcontrast studies (n = 17), revealed 4 splenic, 3 hepatic, 1 pancreatic, 3 renal, and 2 bowel and mesenteric injuries beyond what was found on noncontrast CT. Surgical confirmation (n = 21) was obtained in 81.81 % of splenic, 66.66 % of hepatic, 83.33 % of pancreatic, 100 % of renal, 100 % of retroperitoneal, and 85.71 % of bowel and mesenteric injuries. The majority of false diagnoses was obtained with noncontrast studies. Computed tomography is a remarkable method for evaluation and management of patients with hemodynamically unstable abdominal trauma, but only if it is revealed in the emergency room. Contrast injection, when it could be done, revealed lesions that were not suspected on initial plain scans. Received: 13 March 1997; Revision received: 1 December 1997; Accepted: 6 May 1998     

Lipomatous tumors of soft tissue: MR appearance with histological correlation

There is a broad spectrum of lipomatous tumors that involve soft tissues including ordinary lipomas, variants of lipomas, heterotopic lipomas, lipomatosis, hibernomas and liposarcomas. The recognition of these tumors is important to avoid diagnostic pitfalls. The MR imaging appearance of the lesion, including location, shape and internal architecture, suggests the diagnosis of lipomatous tumors. The signal intensity on T1-, T2-, fat-suppressed T2-weighted (FS-T2) images or short tau inversion recovery (STIR), T1- and fat-suppressed T1-weighted images after Gd-DTPA administration can be a useful aid in distinguishing between biologically different types of lipomatous tumors. The imaging features are often characteristic and reflect the histological pattern of the tumors.

We present an overview of the lipomatous tumors and we correlate MR imaging appearance with histological findings.     

Imaging of peripheral nerve sheath tumors with pathologic correlation: pictorial review

Peripheral neurogenic tumors include neurilemoma, neurinoma, and malignant peripheral nerve sheath tumors. All neurogenic tumors share common imaging features. Although differentiation between them is difficult, neurogenic origin can be suggested from their imaging appearances, including fusiform shape, relation to the nerve, "split-fat" sign, associated muscle atrophy and intrinsic imaging characteristics including "target sign" as well as from lesion location along a typical nerve distribution. Our purpose is to make an overview of imaging findings of each type of peripheral nerve sheath tumor with emphasis on characteristic signs and correlate with histologic features. Morton's neuroma and intraneural ganglion are also included as tumors of nerve origin.     

Effects of ultrasound on the growth and function of bone and periodontal ligament cells in vitro

The effects of therapeutic ultrasound (US) on tissue healing processes in vivo are likely to involve US-induced changes in key cellular functions. However, these have not yet been clearly delineated and the present study has, therefore, examined the effects of a single 5-min CW exposure of 3.00-MHz US on the growth and functional activity of a human osteoblast-like cell line (MG63 cells) and human periodontal ligament (PDL) cells in vitro. Although cell proliferation was found to be largely unaffected by spatial average intensity (I(SA)) values of between 140-990 mW/cm(2), flow cytometry (FCM) analysis showed that there were pronounced and differential effects on cell function. Thus, bone-associated proteins were down-regulated, whereas collagen type I (COL I) was unaffected and fibronectin (FN) was up-regulated at low intensities in MG63 cells. In contrast, bone protein expression was found to be dose-dependent, and FN and COL I were down-regulated in PDL cells. These results show that US has potentially important effects on the functional activities of connective tissue cells in vitro, which could markedly influence tissue repair and regeneration processes in vivo.