title: [Atipic osteosarcoma in the femoral shaft case report and review of the literature].
abstract: Osteosarcoma is the most frequent primary malignant bone tumor. It is characterized by osteoid production by tumor cells. Its most frequent location is in the metaphyses of long bones, but a purely diaphyseal presentation is reported in 10% of cases. We report the case of a female 25 year-old patient whose symptoms of pain and swelling of the right mid thigh started four months before, without an apparent cause. Femur X-rays showed a tumor in the femoral shaft. The MRI showed extension to soft tissues with no compromise of the neurovascular bundle. The histopathologic report of the incisional biopsy was osteoblastic and chondroblastic osteosarcoma, classified as Enneking IIB, AJCC IIB. Treatment consisted of three cycles of neoadjuvant chemotherapy. Then intercalary femur resection plus reconstruction with centromedullary nailing and a diaphyseal spacer were performed. The histopathologic report was 95% necrosis (Huvos grade III). Three cycles of adjuvant chemotherapy were given and now, 18 months after completing the latter, the patient has no signs of local or distant tumor activity, and she can walk unassisted. Despite the fact that osteosarcoma does not occur usually in the mid shaft of long bones, we should always bear it in mind as part of the differential diagnosis for other conditions that occur more frequently in that region. Such location allows for a broad gamut of surgical approaches that spare the adjacent joints.
authors.affiliation: Departamento de Piel y Partes Blandas del Instituto Nacional de Cancerología. Secretaría de Salud de México. Av. San Fernando No. 22, Tlalpan, Sección XVI, 14080 Ciudad de México, D.F.
authors.forename: M A
authors.initials: MA
authors.lastname: Clara-Altamirano
authors.affiliation: Departamento de Piel y Partes Blandas del Instituto Nacional de Cancerología. Secretaría de Salud de México. Av. San Fernando No. 22, Tlalpan, Sección XVI, 14080 Ciudad de México, D.F.
authors.forename: D Y
authors.initials: DY
authors.lastname: García-Ortega
authors.affiliation: Departamento de Piel y Partes Blandas del Instituto Nacional de Cancerología. Secretaría de Salud de México. Av. San Fernando No. 22, Tlalpan, Sección XVI, 14080 Ciudad de México, D.F.
authors.forename: J L
authors.initials: JL
authors.lastname: Martínez-Tlahuel
authors.affiliation: Departamento de Piel y Partes Blandas del Instituto Nacional de Cancerología. Secretaría de Salud de México. Av. San Fernando No. 22, Tlalpan, Sección XVI, 14080 Ciudad de México, D.F.
authors.forename: H
authors.initials: H
authors.lastname: Martínez-Said
authors.affiliation: Departamento de Piel y Partes Blandas del Instituto Nacional de Cancerología. Secretaría de Salud de México. Av. San Fernando No. 22, Tlalpan, Sección XVI, 14080 Ciudad de México, D.F.
authors.forename: C H S
authors.initials: CH
authors.lastname: Caro-Sánchez
authors.affiliation: Hospital Central «Dr. Ignacio Morones Prieto», Avenida Venustiano Carranza #2395, Zona Universitaria, 78290 San Luis Potosí, SLP. México.
authors.forename: G C
authors.initials: GC
authors.lastname: García-Ruíz
authors.affiliation: Centro Hospitalario Sanatorio Durango. Durango 296, Cuauhtémoc, Roma Nte., 06700 Ciudad de México, D.F.
authors.forename: C R
authors.initials: CR
authors.lastname: Mejía-Salazar
authors.affiliation: Departamento de Piel y Partes Blandas del Instituto Nacional de Cancerología. Secretaría de Salud de México. Av. San Fernando No. 22, Tlalpan, Sección XVI, 14080 Ciudad de México, D.F.
authors.forename: M
authors.initials: M
authors.lastname: Cuellar-Hubbe
mesh_terms: D000328:Adult; D001859:Bone Neoplasms / Q000000981:diagnostic imaging / Q000601:surgery; D018483:Diaphyses; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging / Q000473:pathology; D006801:Humans; D012516:Osteosarcoma / Q000000981:diagnostic imaging / Q000601:surgery; D011859:Radiography
keywords: Osteosarcoma; diaphysis; femur; treatment