Extraskeletal myxoid chondrosarcoma: multimodal diagnosis and identification of a new cytogenetic subgroup characterized by t(9;17)(q22;q11)

Virchows Arch. 1999 Nov;435(5):524-30. doi: 10.1007/s004280050437.

Abstract

Extraskeletal myxoid chondrosarcoma is a rare malignant soft tissue tumour that can be difficult to diagnose correctly, especially preoperatively. We describe four cases of extraskeletal myxoid chondrosarcoma of the extremities diagnosed by a multimodal approach. The cytological examination of fine-needle aspirates showed small and round, mildly pleomorphic cells lying in sheets and cords, but also dispersed within a myxoid and metachromatic intercellular substance. Histological, electron microscopic and immunocytochemical examination also yielded findings compatible with the diagnosis of extraskeletal myxoid chondrosarcoma. Cytogenetic analysis demonstrated a t(9;22)(q22;q12) in two tumours and a t(9;17)(q22;q11) in the third and fourth. The translocation t(9;22)(q22;q12) has been described repeatedly in extraskeletal myxoid chondrosarcoma but never in other tumours; hence, the detection of this pathognomonic chromosome abnormality in short-term cultured cells from fine-needle aspirates verified the diagnosis in two of the cases. The t(9;17)(q22;q11) found in the last two cases probably represents a new cytogenetic subgroup of extraskeletal myxoid chondrosarcoma as it, too, is unknown in other contexts. The multimodal approach taken in these four cases enabled a definite diagnosis of a rare malignant tumour whose cytological and histological features alone are usually not sufficiently distinct to rule out other differential diagnostic possibilities.

Publication types

  • Case Reports

MeSH terms

  • Aged
  • Chondrosarcoma / classification
  • Chondrosarcoma / diagnosis*
  • Chondrosarcoma / genetics*
  • Chondrosarcoma / ultrastructure
  • Chromosomes, Human, Pair 17 / genetics*
  • Chromosomes, Human, Pair 9 / genetics*
  • Diagnosis, Differential
  • Histocytochemistry
  • Humans
  • Immunohistochemistry
  • Karyotyping
  • Male
  • Microscopy, Electron
  • Middle Aged
  • Muscle Neoplasms / classification
  • Muscle Neoplasms / diagnosis
  • Muscle Neoplasms / genetics*
  • Muscle Neoplasms / ultrastructure
  • Translocation, Genetic*