Gastrointestinal stromal tumours in children and young adults: a clinicopathologic series with long-term follow-up from the database of the Cooperative Weichteilsarkom Studiengruppe (CWS).

BACKGROUND: Studies on gastrointestinal stromal tumours (GIST) in the paediatric population are limited to case reports or small case series. PATIENTS AND METHODS: We conducted a retrospective study to describe the long-term outcome of children and adolescents with GIST registered in the database of the Cooperative Weichteilsarkom Studiengruppe (CWS). RESULTS: Sixteen patients (female, n = 11) were identified. Median age at diagnosis was 13.5 years. In four female patients presence of thoracic masses in addition to GIST led to the diagnosis of complete or incomplete Carney triad. Three female patients had metastatic disease at diagnosis, the remaining thirteen GIST were localised. The stomach was the most common primary site of the tumour, followed by the small bowel and colon/abdomen. All patients underwent tumour resection. Receptor tyrosine kinase inhibitors (RTKI) were administered in five patients. With a median follow-up of 96 months all patients are alive, nine of them in first CR. Four female patients developed local or distant recurrence; three of them achieved second CR and one a PR. Two individuals have extensive progressive (n = 1) or stable (n = 1) disease. Estimated progression-free survival at 5 years is 0.63 (95%CI: 0.50-0.86). CONCLUSIONS: Although long-term overall survival is favourable, approximately 30 percent of patients develop disease progression. International cooperation in registration, tissue collection and molecular studies are required to obtain reliable data on the clinical course of these rare tumours in the paediatric population. Biological studies are a prerequisite for initiation of studies with RTKI.

Autoimmune lymphoproliferative syndrome (ALPS) caused by Fas (CD95) mutation mimicking sarcoidosis.

Autoimmune lymphoproliferative syndrome (ALPS) is an inherited disorder associated with defects in apoptosis, characterized by childhood onset of lymphadenopathy, splenomegaly, hyperimmunoglobulinemia, and autoimmune disease. ALPS is most frequently associated with a mutation in the cell death receptor Fas (CD95). Very rarely a mutation in caspase 10 is present. An increase of CD4/CD8 double negative T cells in the peripheral blood and lymph nodes is a feature characteristic of ALPS. Additionally, histiocytic proliferations resembling sinus histiocytosis with massive lymphadenopathy (Rosai-Dorfman disease) were reported recently in patients with ALPS. In the rare cases with a caspase 10 mutation an accumulation of dendritic cells in lymphoid organs was noted. We describe a different, sarcoidosislike, histiocytic infiltration of lymph nodes that persisted for years in a girl, that was initially supposed to suffer from sarcoidosis, but was eventually diagnosed as ALPS, associated with a missense mutation in the intracellular death domain of Fas. This sarcoidosislike histologic picture extends the spectrum of histiocytic lymph node alterations observed in ALPS and alerts of a potential diagnostic pitfall.

Screening for leukemia- and clone-specific markers at birth in children with T-cell precursor ALL suggests a predominantly postnatal origin.

Childhood T-cell precursor acute lymphoblastic leukemia (TCP ALL) is an aggressive disease with a presumably short latency that differs in many biologic respects from B-cell precursor (BCP) ALL. We therefore addressed the issue of in utero origin of this particular type of leukemia by tracing oncogenic mutations and clone-specific molecular markers back to birth. These markers included various first- and second-hit genetic alterations (TCRD-LMO2 breakpoint regions, n = 2; TAL1 deletions, n = 3; Notch1 mutations, n = 1) and nononcogenic T-cell receptor rearrangements (n = 13) that were derived from leukemias of 16 children who were 1.5 to 11.2 years old at diagnosis of leukemia. Despite highly sensitive polymerase chain reaction (PCR) approaches (1 cell with a specific marker among 100,000 normal cells), we identified the leukemic clone in the neonatal blood spots in only 1 young child. These data suggest that in contrast to BCP ALL most TCP ALL cases are initiated after birth.