title: Extraskeletal osteosarcoma with partial spontaneous regression.
abstract: Resection for a mass in the proximal thigh was performed on a 57-year-old woman, the diagnosis of which was extraskeletal osteosarcoma. In pathological findings, tumor cells gradually decreased from the central area of the mass composed of spindle cell sarcoma and were replaced by fibrocollagenous tissue with no sarcoma cells. CD8(+), T-cell-restricted intracellular antigen-1 (TIA-1)(+), granzyme B(+) T lymphocytes appeared to infiltrate the mass lesion, so that we hypothesize that the immunological system was likely to be involved via T lymphocytes in triggering spontaneous regression in this case. One of the most unusual phenomena in cancer biology is the spontaneous regression of a tumor. Here, we report on the first case of extraskeletal osteosarcoma characterized by partial spontaneous regression of the primary lesion.
authors.affiliation: Department of Artificial Joints and Biomaterials, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan. tomatsuo@hiroshima-u.ac.jp
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Matsuo
authors.forename: Shoji
authors.initials: S
authors.lastname: Shimose
authors.forename: Tadahiko
authors.initials: T
authors.lastname: Kubo
authors.forename: Yukio
authors.initials: Y
authors.lastname: Mikami
authors.forename: Koji
authors.initials: K
authors.lastname: Arihiro
authors.forename: Yuji
authors.initials: Y
authors.lastname: Yasunaga
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Ochi
mesh_terms: D001859:Bone Neoplasms / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D008875:Middle Aged; D012516:Osteosarcoma / Q000473:pathology* / Q000601:surgery; D012075:Remission, Spontaneous; D012983:Soft Tissue Neoplasms / Q000473:pathology* / Q000601:surgery