title: Use of electron microscopy and other special techniques in the investigation of suspected specimen contamination.
abstract: Contamination of a biopsy or surgical specimen with spurious tissue is an uncommon but potentially disastrous event. In this regard, the case of a 5-year-old boy referred for treatment of an abdominal tumor is presented. Sections made from paraffin blocks brought by the family showed both neuroblastoma and a spindle cell sarcoma, initially suggesting the possibility of divergent or mixed differentiation. However, the resemblance of the spindle cell component to well-differentiated leiomyosarcoma rather than rhabdomyosarcoma raised the suspicion that a specimen contamination had occurred. Electron microscopy was instrumental in confirming the smooth muscle nature of the sarcomatous component, leading to a fluorescence in situ hybridization study, which established that this component was incompatible with the patient's gender. This case illustrates that even when the light microscopic differential has been compromised by specimen mishandling, electron microscopy can at times provide useful information regarding specimen identity, as well as assist in sorting out the correct diagnosis.
authors.affiliation: Department of Pathology, Loma Linda University, California, USA.
authors.forename: C W
authors.initials: CW
authors.lastname: Zuppan
authors.forename: D A
authors.initials: DA
authors.lastname: Weeks
authors.forename: G D
authors.initials: GD
authors.lastname: Wenger
authors.forename: O A
authors.initials: OA
authors.lastname: Alvarez
authors.forename: G W
authors.initials: GW
authors.lastname: Mierau
mesh_terms: D000199:Actins / Q000032:analysis; D002675:Child, Preschool; D003937:Diagnosis, Differential; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D019300:Medical Errors; D008577:Meningeal Neoplasms / Q000556:secondary; D009447:Neuroblastoma / Q000737:chemistry / Q000175:diagnosis* / Q000648:ultrastructure; D016612:Paraffin Embedding; D009418:S100 Proteins / Q000032:analysis; D012509:Sarcoma / Q000737:chemistry / Q000175:diagnosis* / Q000648:ultrastructure; D014960:X Chromosome / Q000737:chemistry; D014998:Y Chromosome / Q000737:chemistry
chemical_list: D000199:Actins; D009418:S100 Proteins