title: [False positive with Tl-201 in the study of Ewing's sarcoma of the astragalus caused by reflex sympathetic dystrophy].
abstract: We describe a 14 year old male, diagnosed of Ewing sarcoma in left astragalus. We performed two 201-Thallium scan for evaluating the response to chemotherapy (before and after the treatment). The scan performed after chemotherapy showed patchy uptake in astragalus, calcaneus and some joints of the foot. The following radiology and scintigraphy diagnosed a reflex sympathetic dystrophy in the left foot due to disuse of the limb. The 201-Thallium overestimated viability of the tumour for this reason. We must discard the presence of this kind of associated pathology in order that they could be cause of false positives.
authors.affiliation: Servicio de Medicina Nuclear y Traumatología. Hospital Universitario San Juan de Alicante.
authors.forename: J
authors.initials: J
authors.lastname: Serrano Vicente
authors.forename: O
authors.initials: O
authors.lastname: Caballero Carpena
authors.forename: J
authors.initials: J
authors.lastname: Verdú Rico
authors.forename: R
authors.initials: R
authors.lastname: Alcalá Santaella
authors.forename: A
authors.initials: A
authors.lastname: Martínez Cabllero
authors.forename: M A
authors.initials: MA
authors.lastname: Antón Leal
mesh_terms: D000293:Adolescent; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001859:Bone Neoplasms / Q000150:complications / Q000000981:diagnostic imaging* / Q000188:drug therapy; D002111:Calcaneus / Q000000981:diagnostic imaging; D003937:Diagnosis, Differential; D005189:False Positive Reactions; D006801:Humans; D008297:Male; D009361:Neoplasm Invasiveness / Q000000981:diagnostic imaging; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D012019:Reflex Sympathetic Dystrophy / Q000000981:diagnostic imaging* / Q000209:etiology; D012512:Sarcoma, Ewing / Q000150:complications / Q000000981:diagnostic imaging* / Q000188:drug therapy; D013628:Talus / Q000000981:diagnostic imaging*; D013794:Thallium Radioisotopes / Q000493:pharmacokinetics
chemical_list: D019275:Radiopharmaceuticals; D013794:Thallium Radioisotopes
vernacular_title: Falso positivo con T1201 en el estudio de un sarcoma de Ewing de astrágalo causado por una distrofia simpático-refleja.