MR imaging evaluation of subacute and chronic bone abscesses in children

Objective. The aim of the present study was to assess the value of magnetic resonance (MR) imaging in subacute and chronic bone abscesses in children. ¶Materials and methods. Seventy-four patients underwent MR imaging because of suspected musculoskeletal infections between January 1996 and January 1999 in Montreal Children's Hospital. The clinical, radiographic, scintigraphic and MR imaging features of patients with a bone abscess were studied. ¶Results. Eleven patients had osteomyelitis with no bone abscess and six had osteomyelitis with a subacute or chronic bone abscess. Although the lucency was eventually seen on plain radiographs in all cases, MR imaging made a significant contribution, as it helped narrow the differential diagnosis and showed better delineated medullary involvement and extension into the epiphysis. ¶Conclusion. MR imaging is valuable in the diagnostic evaluation of children with bone infection and abscess. It reveals the extent of subperiosteal and epiphyseal involvement not seen on plain radiographs. The extent of the medullary involvement around the abscess is best visualized with MR imaging, which can also distinguish between isolated soft tissue infection adjacent to bone and true bone infection.     

Giant inflammatory polyposis causing partial obstruction and pain in "healed" ulcerative colitis in an adolescent

A 16-year-old boy with chronic ulcerative colitis developed unexplained increasingly intractable abdominal pain and rectal bleeding over several months during a period when acute colitic attacks were quiescent. No abdominal mass was palpable. The cause of symptoms was subtotal colonic obstruction due to the development of massive or giant inflammatory (pseudo) polyposis, which had caused nearly complete obliteration of the lumen of the transverse colon. The radiological and histopathological findings are presented; this case confirms the conclusion drawn in a recent retrospective surgical pathology report that giant inflammatory polyposis may produce distinct symptoms, especially pain, independent of the existence of relatively quiescent underlying inflammatory bowel disease. This unusual complication of inflammatory bowel disease deserves greater clinical awareness.     

Cytotoxic T lymphocyte antigen 4 and CD28 modulate cell surface raft expression in their regulation of T cell function.

Coreceptors CD28 and cytotoxic T lymphocyte antigen (CTLA)-4 have opposing effects on TcR/CD3 activation of T cells. While CD28 enhances and CTLA-4 inhibits activation, the underlying molecular basis of these effects has yet to be established. In this context, ganglioside and cholesterol enriched membrane microdomains (rafts, GEMs) serve as centers of signaling in T cells. Although CD28 can promote TcR/raft colocalization, evidence is lacking on whether the surface expression of membrane rafts can be targeted by CTLA-4 in its modulation of T cell responses. In this study, we demonstrate that both CD28 and CTLA-4 profoundly alter the surface expression of membrane rafts during T cell activation. While CD28 increased expression and the number of peripheral T cells induced to express surface rafts in response to TcR ligation, CTLA-4 potently inhibited both TcR and TcR x CD28 induced raft expression on the surface of T cells. Consistent with this, CD28 increased the presence of the linker of activated T cells (LAT) in purified membrane rafts, while CTLA-4 coligation effectively blocked this increase. Further, the reversal of the CTLA-4 block with CD3/CD28 ligation was accompanied by an increase in surface raft expression and associated LAT. Our observations demonstrate for the first time that CTLA-4 targets the release of rafts to the surface of T cells, and provides a mechanism for the opposing effects of CD28 and CTLA-4 on costimulation.     

Breast lymphoma complicating anti-tumor necrosis factor therapy in rheumatoid arthritis

The relationship between anti-TNF therapy and development of lymphoma in Rheumatoid arthritis (RA) patients is controversial. However lymphomas of unusual types and sites have been reported among RA patients receiving anti-TNF therapy. Primary lymphoma of the breast is a rare entity and has never been reported to occur among RA patients taking anti-TNF therapy. This is the first case of primary lymphoma of the breast reported among RA patients on anti-TNF therapy. Rheumatoid arthritis patients currently on anti-TNF therapy should undergo routine gynecological examination.     

Juvenile spondyloarthropathies: clinical manifestations and medical imaging

The spondyloarthropathies comprise four distinct entities — ankylosing spondylitis, psoriatic arthritis, the arthritis associated with inflammatory bowel disease, and Reiter's syndrome and other related forms of reactive arthritis. Although these are distinct diseases, they have a number of clinical, radiologie, and genetic characteristics in common which permit them to be classified under the unifying term spondyloarthropathy. They are diseases of young adults, and when they present in patients under 16 years of age we refer to them as the juvenile spondyloarthropathies. They must be distinguished from juvenile rheumatoid arthritis, which is a totally separate entity; however the distinction may not always be obvious. Involvement of peripheral and sacroiliac joints commonly occurs in the juvenile spondyloarthropathies. The peripheral arthritis may be erosive and associated with bone apposition at the joint margins. Axial involvement is usually a late finding. Dactylitis and tenosynovitis are frequently present early on. Enthesitis, a highly specific feature, occurs much more often in the juvenile spondyloarthropathies than in the adult forms and it may be the only presenting feature. The plain radiograph is the primary and most important imaging modality for the assessment of these diseases. However, an expanding role of magnetic resonance imaging is evident.Presented in part at the 55^th Annual Meeting of the Canadian Association of Radiologists, Halifax, Nova Scotia, June 25, 1992, and as a Refresher Course at the International Skeletal Society meeting, Toronto, Ontario, August 19, 1993.     

Acrania: a manifestation of the Adams-Oliver syndrome.

A 10-year-old male with acrania, distal limb anomalies, and abnormal arterial and venous cranial blood vessels is reported. Parental films and examination are normal. This case supports the hypothesis that acrania is a severe form of aplasia cutis congenita and is within the spectrum of Adams-Oliver syndrome. It is proposed that the diagnosis of acrania requires assessment of both parents and proband to assess other manifestations of vascular disruption in order to provide accurate genetic counselling.     

Papers presented at the 2nd North American Conference on Angelman syndrome: Introduction

We report on a boy with hyperphalangism, partial syndactyly, facial anomalies, and diffuse bronchomalacia, born to a nonconsan-guineous French-Canadian couple. To our knowledge, this is a hitherto undescribed syndrome. © 1993 Wiley-Liss, Inc.     

Metaphyseal chondrodysplasia,type Jansen

The Jansen type of metaphyseal dysplasia is a rare disorder with significant clinical and radiographic variability. Two cases of classical Jansen disease and one with some distinctive features suggestive of the Jansen variant are reported.