Giant mediastinal liposarcoma: a case report.

Liposarcomas are extremely rare in the mediastinum. They may achieve considerable size before causing any symptoms. Mediastinal liposarcomas may invade surrounding structures like the pericardium or the superior vena cava. Complete surgical excision is the optimal treatment in resectable cases. Excision of adjacent structures like the pericardium may be needed if the tumor infiltrates them. We report on a case of a giant liposarcoma of the mediastinum involving both hemithoraces and extending into the neck, which was successfully managed by complete surgical excision.     

Complete duplication of urinary bladder and urethra: prenatal sonographic features.

Prenatal sonographic features of the rare anomaly of complete duplication of the urinary bladder and urethra are described in this case report. A coronal scan of the fetal pelvis at 29 weeks of gestation revealed two pyriform cystic structures. The umbilical arteries coursed around both of them. They emptied independently of each other. Postnatally the newborn had two vulvae, two anal openings, two bladders and two uteri.     

Toll-like receptor 9 ligand blocks osteoclast differentiation through induction of phosphatase.

CpG-ODN, in addition to stimulation of osteoclastogenic signals in early osteoclast precursors, also induces phosphatase, shifting the pattern of ERK phosphorylation from sustained to transient. This shift results in the degradation of c-fos, an essential molecule for osteoclast differentiation. Therefore, CpG-ODN blocks osteoclast differentiation. INTRODUCTION: Activation of either Toll-like receptor 9 (TLR9) or RANK induces similar responses in osteoclast precursors. Paradoxically, activation of TLR9 results in inhibition of RANKL-induced osteoclastogenesis. MATERIALS AND METHODS: We used bone marrow-derived osteoclast precursors. Analyses of signaling molecules phosphorylation were performed using Western blotting. Different levels of gene expression analyses were performed using RT-PCR, Northern, and run-on analyses (for RNA), and EMSA, Western, and pulse-chase experiments (for protein). Phosphatase activity was measured spectrophotometrically. RESULTS: We found that RANKL and TLR9 ligand, oligodeoxynucleotides containing unmethylated CpG dinucleotides (CpG-ODN), induce sustained and transient extracellular signal-regulated kinase (ERK) phosphorylation, respectively. Furthermore, together they induce a transient phosphorylation of ERK. The duration of ERK phosphorylation is a key factor in determining induction of c-fos, a protein critical for osteoclastogenesis. Indeed, we found that CpG-ODN does not induce c-fos and inhibits its induction by RANKL by enhancing c-fos mRNA and protein degradation. Our observation that CpG-ODN, but not RANKL, induces the expression of the phosphatase PP2A suggests that CpG-ODN exerts its inhibitory activity by induction of ERK dephosphorylation. Moreover, together with the phosphatase inhibitor okadaic acid, CpG-ODN induces sustained ERK phosphorylation and c-fos expression. CONCLUSIONS: Our findings suggest that the increased rate of c-fos degradation by the TLR9 ligand mediates the inhibition of RANKL-induced osteoclast differentiation. The TLR9 ligand, through induction of dephosphorylation, prevents the sustained ERK phosphorylation needed for maintaining high c-fos levels that are essential for osteoclast differentiation.     

Iron-mobilizing properties of the gadolinium-DTPA complex: clinical and experimental observations.

BACKGROUND: Gadolinium (Gd) magnetic resonance imaging (MRI) contrast agents are considered to be safe in patients with impaired renal function. Our study investigates a mechanism of severe iron intoxication with life-threatening serum iron levels in a haemodialysis patient following MRI with Gd-diethylenetriaminepentaacetic acid (Gd-DTPA) administration. His previous history was remarkable for multiple blood transfusions and biochemical evidence of iron overload. We hypothesized that Gd-DTPA may have an iron-mobilizing effect in specific conditions of iron overload combined with prolonged exposure to the agent. METHODS: For the in vitro study, Gd-DTPA was added to mice liver homogenate and iron metabolism parameters were measured after incubation in comparison with the same samples incubated with saline only. For the in vivo study, an experimental model of acute renal failure in iron-overloaded rats was designed. Previously iron-overloaded and normally fed rats underwent bilateral nephrectomy by renal pedicle ligation, followed by Gd-DTPA or saline injection. Iron and iron saturation levels were checked before and 24 h after Gd-DTPA or vehicle administration. RESULTS: Significant mobilization of iron from mice liver tissue homogenate in mixtures with Gd in vitro was seen in the control (saline) and in the experimental (Gd) groups (513+/-99.1 vs 1117.8+/-360.8 microg/dl, respectively; P<0.05). Administration of Gd-DTPA to iron-overloaded rats after renal pedicle ligation caused marked elevation of serum iron from baseline 143+/-3.4 to 570+/-8 microg/dl (P<0.0001). There were no changes of the named parameter, either in iron-overloaded anuric rats after saline injection or in normal diet uraemic animals, following Gd-DTPA administration. CONCLUSIONS: The combination of iron overload and lack of adequate clearance of Gd chelates may cause massive liberation of iron with dangerous elevation of free serum iron. It is highly recommended that after Gd contrast study, end-stage renal disease patients with probable iron overload should undergo prompt and intensive haemodialysis for prevention of this serious complication.     

Epithelioid hemangioendothelioma of bone--a clinicopathologic and immunohistochemical study of 7 cases

Epithelioid hemangioendothelioma is a rare vascular tumor of bone. Between 1987-1999, seven cases of epithelioid hemangioendothelioma were recorded. The histopathological evaluation was done with hematoxylin and eosin stain and immunohistochemical stains along with the analysis of clinical data and X-ray findings. There were 4 males, 3 females between 15 to 48 years of age with complaints of pain and swelling. Long bones were involved in five of the seven patients and one was multifocal. Radiologically all seven patients showed osteolytic lesions. The histologic hall mark was the presence of eosinophilic, epithelioid cells with intracytoplasmic vacuoles. The tumor may be histologically confused with metastatic carcinoma, chondromyxoid fibroma and osteogenic sarcoma. Immunohistochemical reactivity was as follows: Vimentin (6/6 cases), Factor VIII related antigen (4/6 cases), Ulex Europeaus (5/6 cases), CD31 (3/5 cases), CD34 (3/5 cases), epithelial membrane antigen (1/6 cases), cytokeratin (none). Treatment comprised curettage (4 cases), wide excision (2 cases), below knee amputation (1 case) and post operative radiotherapy (2 cases). At follow-up, (available in 4 patients) two were without disease at 18 months and 120 months. Of the remaining two, one developed local recurrence after 36 months; while the other died of lung metastasis (18 months). A lytic bone shadow, the presence of plump eosinophilic often vacuolated cells on a myxoid background and immunohistochemistry together help in the correct recognition of this tumor.