MRI appearances of dysplasia epiphysealis hemimelica of the knee

 Objective. The study was undertaken to describe the magnetic resonance imaging (MRI) appearances of dysplasia epiphysealis hemimelica (DEH) of the knee and to determine whether MRI provides additional information concerning the anomaly compared with more traditional methods of diagnosis. Design and patients. The subjects of the study were three children (one girl and two boys, aged 13 months, 3 years and 11 years) with DEH of the knee. All the patients had plain films of the knee and MRI scans. Results and conclusion. Plain radiographs showed bone overgrowth and asymmetrical ossification centres with adjacent scattered calcifications which coalesced to form a lobulated irregular mass. MRI showed a definite cartilaginous or osteocartilaginous lesion. Its origin from the epiphysis was much more clearly defined. MRI showed the extent of the lesion non-invasively, as well as any potential cleavage plane between the epiphysis and the mass lesion. Abnormal surface nodularity and joint involvement could be determined. It is concluded that plain films supplemented with MRI provide the greatest amount of diagnostic information in cases of DEH. MRI is useful to show the exact location and extent of the lesion, any joint involvement and any potential cleavage between the epiphysis and the mass lesion.     

Rebound thymic hyperplasia in a child with cancer

A case of biopsy-proven thymic hyperplasia is described in a child with group I paratesticular rhabdosarcoma while on chemotherapy. Other cases of children with cancer reported with this phenomenon are reviewed. Tissue diagnosis is important to differentiate metastatic tumor and to rule out second malignancies in these patients. The initial evaluations are facilitated by CT scanning of the chest and upper extremity venography.     

Radiographic gradation of lumbosacral dysgenesis.

The caudal dysgenesis syndrome comprises partial or complete agenesis of the lumbosacral vertebrae, as well as associated musculoskeletal, neurologic and visceral abnormalities. Maternal diabetes mellitus appears to be the most important etiologic factor, but for most patients the etiology is unknown. In the majority of cases, radiologic diagnosis is established readily, but minor degrees often coinciding with a serious urologic disease or a lower limb abnormality may be overlooked.     

Longitudinal CT of the forearm in children

With proper positioning, direct longitudinal computed tomography of the forearm has been tried in five children. Combined with plain radiographs and transverse cuts, it allows a three-dimensional evaluation of bone and soft-tissue lesions. Being in the appropriate plane, it is also of great help in the study of the growth plate of the distal radius.     

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.     

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.     

Skeletal and cardiac malformations with thrombocytopenia: A new syndrome?

We describe a female patient with multiple anomalies suggestive of a new syndrome. Manifestations include: VSD and ASD, mild developmental delay, conductive hearing loss, minor facial anomalies, thrombocytopenia, and radiological findings (including carpal fusion). Some of these manifestations may be present in the Keutel syndrome, IVIC syndrome, and the 10qter deletion syndrome. However, none of these syndromes can explain the spectrum of anomalies seen in our patient. © 1996 Wiley-Liss, Inc.     

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.     

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.