title: [Spindle cell lipoma and 13q deletion: diagnostic utility of cytogenetic analysis].
abstract: OBJECTIVE
  Spindle cell lipomas are rare adipose tissues tumors. Histologically, these lesions are composed of mature adipocytes and spindle cells associated with collagen bundles. Spindle cell lipomas are benign tumors that can be difficult to distinguish from malignant tumors such as spindle cell liposarcomas, myxoid liposarcomas or well-differentiated liposarcomas.
  
  
  RESULTS
  We report herein the description of two new cases. The first case was a deeply situated and infiltrating tumor located in the retromastoidian area. The karyotype showed the presence of two chromosomal abnormalities, a partial deletion of the long arm of chromosome 13, del(13)(q12) and a balanced reciprocal translocation t(2;6)(p16~21;p21). The second case was a subcutaneous tumor of posterior cervical localization. The karyotype showed a 13q deletion associated with a complex rearrangement of chromosomes 5, 6 and 10. The presence of the 13q deletion allowed us to confirm the diagnosis of spindle cell lipoma in both cases. This deletion has been previously described in six out the eleven published karyotype reports. The 13q deletion is usually associated with partial monosomy 16. The present case confirms that it can occur independently. The 6p21 rearrangement may also play a role in the pathobiology of this tumor, as suggested by the positive HMGIY expression detected by immunohistochemistry.
  
  
  CONCLUSIONS
  Our study further illustrates that spindle cell lipomas can infiltrate the surrounding muscle and emphasizes the usefulness of cytogenetic analysis in the differential diagnosis of soft tissue tumors.
authors.affiliation: Service d'Anatomie Pathologique, Hôpital Bellevue, 42055 Saint-Etienne Cedex 2, France.
authors.forename: J M
authors.initials: JM
authors.lastname: Dumollard
authors.forename: D
authors.initials: D
authors.lastname: Ranchère-Vince
authors.forename: F
authors.initials: F
authors.lastname: Burel
authors.forename: J M
authors.initials: JM
authors.lastname: Coindre
authors.forename: G
authors.initials: G
authors.lastname: Tallini
authors.forename: A H
authors.initials: AH
authors.lastname: Ligon
authors.forename: R
authors.initials: R
authors.lastname: Mayaud
authors.forename: C
authors.initials: C
authors.lastname: Turc-Carel
authors.forename: C
authors.initials: C
authors.lastname: Martin
authors.forename: J F
authors.initials: JF
authors.lastname: Mosnier
authors.forename: F
authors.initials: F
authors.lastname: Pedeutour
mesh_terms: D002869:Chromosome Aberrations; D002879:Chromosomes, Human, Pair 10; D002882:Chromosomes, Human, Pair 13; D002889:Chromosomes, Human, Pair 2; D002895:Chromosomes, Human, Pair 5; D002896:Chromosomes, Human, Pair 6; D020732:Cytogenetic Analysis; D003937:Diagnosis, Differential; D017353:Gene Deletion; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D008067:Lipoma / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D018205:Neoplasms, Adipose Tissue / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology; D014178:Translocation, Genetic