Radiologic-Pathologic Correlation Pleomorphic myofibrosarcoma of the tibia with aneuploid DNA content Fernando A. Candanedo Gonzalez, MD, MsC a, ⁎ , Arturo Cerbulo Vazquez, PhD b , Candelaria Cordova Uscanga, MD a , Ivan Jacinto Cortes, MD a , Domínguez Malagon, MD c a Department of Pathology, Oncology Hospital, National Medical Center Century XXI, IMSS, CP 06720 México b Unit of Cytometry, Department of Infectology and Perinatal Immunology, National Institute of Perinatology, CP 06720 México c Department of Pathology, National Institute of Cancerology, Mexico City, CP 14080 Mexico Abstract Myofibrosarcomas of the tibia are exceedingly rare, with only one case reported in the literature. We describe DNA ploidy of high-grade myofibrosarcoma of the tibia in correlation with clinicomorphologic and ultrastructural features in a 16-year-old adolescent girl. Radiological studies revealed an expanding osteolytic bone lesion in the metaphysis of proximal tibia. A biopsy was consistent with malignant fibrous histiocytoma. The final diagnosis of myofibrosarcoma was supported by light microscopy and corroborated by electron microscopy and immunohistochem- istry findings. The DNA content analysis showed an aneuploid tumor. She developed local recurrence at 6 months after initial treatment with no evidence of lung metastases and 16 months later is alive with persistence of disease. This is the second case reported in the literature with this location. In this case, the high grade correlated with recurrence behavior and aneuploidy DNA content but not with metastases. By ultrastructural analyses, fibronexus and intracellular collagen persisted in high-grade myofibrosarcoma. © 2007 Elsevier Inc. All rights reserved. Keywords: Myofibrosarcoma of tibia; Ultrastructural features; Fibronexus; DNA content; Recurrence 1. Introduction Myofibrosarcomas are rare tumors of myofibroblasts occurring mainly in the soft tissue of the head and neck, extremities, and trunk, with only a few primary cases of the bone reported [1-4]. However, primary myofibrosarcomas of the tibia are exceedingly rare, with only one case reported in the literature [4]. Myofibrosarcomas display a range of appearances from fasciitis-like neoplasms to high-grade sarcomas. Low- grade myofibrosarcomas are distinct from high-grade or pleomorphic myofibrosarcomas, which resemble a storiform- pleomorphic malignant fibrous histiocytoma (MFH) [5]. Radical surgery with a wide local excision is the treatment of choice in these patients. Nevertheless, after resection, some cases showed local recurrences within a short time [4]. However, biological markers able to identify patients with higher risk of recurrence are lacking. On the other hand, flow cytometric DNA analysis for determination of aggressive behavior of this tumor type has seldom been tested. A correlation between aneuploid tumors and recurrence or metastases has been reported in a heterogeneous group of myofibroblastic tumors [6], but no reports had established a relationship between DNA ploidy in myofibrosarcoma of bone and histology grade. We showed the clinicomorphologic and ultrastructural features and the DNA content of high-grade myofibrosarcoma of the tibia in a young Mexican woman. 2. Case report A 16-year-old adolescent girl presented with pain of the right leg associated with functional limitation and enlarge- ment of 3 months of duration. She was admitted at the Oncology Hospital in January 2005. Radiographic and computed tomographic scan showed expanding osteolytic bone lesion with a thin sclerotic rim and periosteal reaction in the metaphysis of proximal tibia. A biopsy was diagnosed as consistent with MFH. A local excision of the tumor was performed, and the tumor was removed completely with negative margins. She received one cycle of adjuvant Annals of Diagnostic Pathology 11 (2007) 340 – 344 ⁎ Corresponding author. Tel.: +52 627 6900x22732; fax: +52 5513 53 95. E-mail address: fa_candanedo@yahoo.com.mx (F.A.C. Gonzalez). 1092-9134/$ – see front matter © 2007 Elsevier Inc. All rights reserved. doi:10.1016/j.anndiagpath.2007.04.002