title: Concurrent Ewing sarcoma family of tumors and fibrous dysplasia: possible diagnostic pitfall.
abstract: We present 2 patients with synchronous Ewing sarcoma family of tumors (ESFTs) and fibro-osseous lesion in the independent sites, possibly causing misjudgment in staging. Each patient showed another activity apart from the primary ESFT lesion on gallium and/or thallium scintigraphy at initial presentation. Of note is that such lesions showed no obvious radiologic change even though the primary ESFT lesions were mildly shrunken during chemotherapy. The biopsies confirmed fibrous dysplasia (FD) in the first patient and fibro-osseous lesion, possibly FD in the second patient. As far as we know, concurrent ESFT and FD in independent sites have never been described. However, this unusual combination emphasized the possibility of concurrent FD mimicking metastasis in a patient with malignancy and the view that exploratory biopsy should be performed in a critical case to make staging. Further investigation will be required about whether the co-occurrence of ESFD and FD in our patients is coincidence or genetic linkage.
authors.affiliation: Division of Pathology, Kanagawa Children's Medical Center, Yokohama, Japan. kato5577@d2.dion.ne.jp
authors.forename: Keisuke
authors.initials: K
authors.lastname: Kato
authors.forename: Tsuyuko
authors.initials: T
authors.lastname: Hayashi
authors.forename: Ken
authors.initials: K
authors.lastname: Tabuchi
authors.forename: Nariharu
authors.initials: N
authors.lastname: Okuzumi
authors.forename: Hisato
authors.initials: H
authors.lastname: Kigasawa
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Abe
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Toyoda
authors.forename: Noriko
authors.initials: N
authors.lastname: Aida
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Sekido
authors.forename: Hironobu
authors.initials: H
authors.lastname: Sato
authors.forename: Mio
authors.initials: M
authors.lastname: Tanaka
authors.forename: Yukichi
authors.initials: Y
authors.lastname: Tanaka
mesh_terms: D000293:Adolescent; D001706:Biopsy; D001859:Bone Neoplasms / Q000473:pathology*; D002648:Child; D003937:Diagnosis, Differential; D005189:False Positive Reactions; D005260:Female; D018214:Fibroma, Ossifying / Q000473:pathology*; D005357:Fibrous Dysplasia of Bone / Q000473:pathology*; D006801:Humans; D008297:Male; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D012512:Sarcoma, Ewing / Q000473:pathology*