FIBROSARCOMA IN INFANTS AND CHILDREN - APPLICATION OF NEW TECHNIQUES

Fibrosarcomas occurring in infants and young children are intriguing t umors. Although biologically more benign than their counterparts occur ring in old patients, they are histologically similar. Microscopically , they fit in one end of a spectrum of fibrous proliferations occurrin g in the pediatric population. Prompted by recent karyotypic reports o f nonrandom gains of chromosomes 8, 11, 17, and 20 in infantile fibros arcomas, we retrospectively analyzed 12 infantile fibrosarcomas utiliz ing fluorescence in-situ hybridization (FISH) with chromosome 8-, 11-, 17-, and 20-specific probes. Parallel studies were performed on fibro sarcomas occurring in older children and young adults and also on cell ular fibromatoses, myofibromatoses, and fibromatoses. Gains of chromos omes 8, 11, 17, and 20 (in various combinations) were observed in 11 o f 12 fibrosarcomas occurring in infants < 2 years of age. Extra copies of chromosomes 17 and 20 were observed in a fibrosarcoma occurring in a 5-year-old child but no abnormalities were detected by FISH in four additional fibrosarcomas occurring in patients aged 6-17 years. One o f three cellular fibromatoses was characterized by extra copies of chr omosome 8, 11, 17, and 20. Similar findings were not observed in any o f the noncellular fibromatoses or in myofibromatoses.