We identified a genomically, histologically, and clinically distinct subgroup of HGGs that harbored somatic POLE mutations and carried an improved prognosis. Identification of distinctive molecular and pathological HGG phenotypes has implications not only for improved classification but also for potential targeted treatments.

The aim of this study was to determine the relative frequency of underlying illnesses for recurrent pneumonia in children. Children who had two or more episodes of pneumonia per year, or three or more episodes in a lifetime were investigated retrospectively at Ankara University Medical School, Department of Pediatric Infectious Diseases, between January 1997 and October 2002. Out of 788 children hospitalized for pneumonia, 71 (9 per cent) met the criteria for recurrent pneumonia. An underlying illness was demonstrated in 60 patients (85 per cent). In this group, the underlying illness was diagnosed prior to pneumonia in 11 patients (18.3 per cent), during the first episode in 12 patients (20 per cent), and during recurrence in 37 patients (61.7 per cent). Underlying diseases were bronchial asthma (32 per cent), gastroesophageal reflux (15 per cent), immune disorders (10 per cent), congenital heart defects (9 per cent), anomalies of the chest and lung (6 per cent), bronchopulmonary dysplasia (4 per cent), cystic fibrosis (3 per cent), tuberculosis (3 per cent), and aspiration syndrome (3 per cent). No predisposing illness could be demonstrated in 11 patients (15 per cent). In conclusion, approximately one-tenth of hospitalized children with pneumonia in our hospital had recurrent pneumonia. Most of these children had an underlying illness, which was demonstrated by intensive investigation. Bronchial asthma in children aged more than 2 years and gastroesophageal reflux in children aged less than 1 year were the most common underlying illnesses for recurrent pneumonia.

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Mesenchymal hamartoma of the liver is a cystic benign liver mass occurring in children. Diagnostic confusion with hepatoblastoma may arise when alpha-feto-protein (AFP) level is elevated. We report an extremely rare case of mesenchymal hamartoma in an 11-month-old boy. Serum AFP was elevated and fine-needle aspiration biopsy suggested the lesion as hepatoblastoma, so he received preoperative chemotherapy. At the end of the preoperative chemotherapy, the tumor size and AFP level decreased. A right hepatectomy was performed. The pathologic examination of the specimen revealed mesenchymal hamartoma. Mesenchymal hamartoma of the liver with increased serum AFP levels may mimic hepatoblastoma if a cytological examination samples only the hepatocellular component of mesenchymal hamartoma. According to our knowledge, this is the first case of the mesenchymal hamartoma of the liver, which showed reduction in serum levels of AFP and involution of the tumor size by preoperative chemotherapy.

Although malignant skin tumors are rare in childhood, the prognosis is relatively better than it is for adults. Malignant melanoma was the most frequent tumor. Forty-three per cent of our patients had an underlying defect in their immune barriers which is thought to be responsible for the development of their malignancies.