Although the presence of granulomas can support a diagnosis of Crohn disease, severe inflammation and other abnormalities occur in the proximal gastrointestinal tract in Crohn disease and ulcerative colitis.

The stem cell factor (SCF)/c-kit ligand/receptor system has been implicated in stem (oval) cell activation following liver injury in the rat. The aim of this study was to determine the role of the SCF/c-kit system in pediatric human liver during acute and chronic liver injury. Tissue was obtained from hepatectomy specimens of patients undergoing liver transplantation for extrahepatic biliary atresia (EHBA) and fulminant hepatic failure (FHF). Specific expression of mRNA for c-kit and ␤-actin was measured by ribonuclease protection and by immunohistochemistry to localize c-kit in tissue sections. Expression of c-kit was detected at relatively consistent levels in normal and cirrhotic (

The outcome of pediatric ependymomas is difficult to predict based on clinical and histological parameters. To address this issue, we have performed a comparative genomic hybridization screen of 42 primary and 11 recurrent pediatric ependymomas and correlated the genetic findings with clinical outcome. Three distinct genetic patterns were identified in the primary tumors and confirmed by hierarchical cluster analysis. The first group of structural tumors, showed few, mainly partial imbalances (n ‫؍‬ 19). A second numerical group showed 13 or more chromosome imbalances with a nonrandom pattern of whole chromosome gains and losses (n ‫؍‬ 5). The remaining tumors (n ‫؍‬ 18) showed a balanced genetic profile that was significantly associated with a younger age at diagnosis (P < 0.0001), suggesting that ependymomas arising in infants are biologically distinct from those occurring in older children. Multivariate analysis showed that the structural group had a significantly worse outcome compared to tumors with a numerical (P ‫؍‬ 0.05) or balanced profile (P ‫؍‬ 0.02). Moreover genetic group and extent of surgical resection contributed significantly to outcome whereas histopathology, age, and other clinical parameters did not. We conclude that patterns of genetic imbalances in pediatric intracranial ependymomas may help to predict clinical outcome. Pediatric ependymomas are enigmatic tumors whose behavior is difficult to predict based on clinical and histological factors. These tumors are thought to derive from ependymal cells lining the ventricular system and fall into the broad group of gliomas.1 Ependymomas comprise ϳ10% of all childhood intracranial neoplasms and with Ͼ50% arising in children younger than 5 years of age present a distinct management challenge.2-4 In contrast to adults in which spinal tumors predominate, Ͼ90% of all pediatric ependymomas are intracranial in origin with most tumors arising infratentorially.2,3,5

Inflammatory myofibroblastic tumours (IMFT) may arise at any anatomical site, including lung, soft tissues, retroperitoneum and bladder. Although morphologically similar, these lesions encompass a spectrum of entities with differing aetiology, ranging from reactive/regenerative proliferations to low-grade neoplasms with a risk of local recurrence, but no significant metastatic potential. Vesical IMFT usually presents as a polypoid mass with a pale firm cut surface and can be of considerable size, mimicking a malignant tumour clinically and radiologically. Its good outcome, however, warrants conservative surgical excision, emphasising the importance of identification and distinction from malignant tumours of the bladder that may require more radical surgery and/or adjuvant therapy. We conducted a preliminary retrospective, comparative immunocytochemical study of 20 bladder tumours, including nine IMFTs, five spindle cell (sarcomatoid) carcinomas, two rhabdomyosarcomas, two leiomyosarcomas and two neurofibromas. The results confirmed IMFT positivity for smooth muscle actin, desmin and cytokeratin in 78-89% cases, resulting in potential confusion with sarcomatoid carcinoma or leiomyosarcoma. In contrast, cytoplasmic anaplastic lymphoma kinase (ALK 1) staining was present in eight IMFT (89%), but was not seen in any other lesion examined. The ALK 1 staining was confirmed by fluorescence in situ hybridisation, with translocation of the ALK gene present in 15-60% tumour cells in four of six IMFT examined, but not in four cases of sarcomatoid carcinoma or three of leiomyosarcoma. In conclusion, ALK 1 staining may be of value in the distinction of vesical IMFT from morphologically similar entities, and often reflects ALK gene translocations in these lesions.

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