Chromosomal abnormality t(9;22)(q22;q12) in an extraskeletal myxoid chondrosarcoma characterized by fine needle aspiration cytology, electron microscopy, immunohistochemistry and DNA flow cytometry.

A multidisciplinary approach was taken to characterize a soft tissue tumour. In smears prepared from aspirated material, uniform tumour cells, embedded in a myxoid matrix and partly arranged in a lace-like pattern, were found. Histopathology showed a lace-like pattern of cells in a matrix of hyaluronidase-stable mucins. Cytoplasmic positivity for S-100 protein was found in some tumour cells. Electron microscopic analysis revealed intracisternal aggregates of microtubules. All these features are consistent with the diagnosis of extraskeletal myxoid chondrosarcoma (EMC). DNA flow cytometry showed a diploid DNA content. Cytogenetic examination revealed the tumour karyotype 45,XY,t(2;11)(q31;p15),t(9;22)(q22.3;q12),dic(13;22)(p11;p13). Because similar 9;22-translocations have been described in two other cases of EMC, we conclude that t(9;22)(q22-31;q11-12) is a specific rearrangement in this tumour type. Cytogenetic analysis may thus be of diagnostic value in the examination of tumours with this and similar histologies.