Cytogenetic characterisation of small round cell tumours using fine needle aspiration.

Cytogenetic analysis of short term cultures of fine needle aspirates from two tumours, characterised cytologically as small round cell neoplasms, showed specific clonal chromosomal abnormalities. In both cases the cytogenetic finding of a t(11; 22) (q24; q12) helped determine their diagnosis as peripheral neuroectodermal tumours of the thoraco-pulmonary region (Askin's tumour). These findings suggest that cytogenetics can reliably distinguish neoplasms which present as undifferentiated small round cell tumours.