This patient has a osteosarcoma that is high grade, extracompartment, and without metastases, so it is a IIB by the MSTS Staging System. This is the most common MSTS stage for a osteosarcoma to present. Here is a review of the stages in the MSTS (Enneking) Staging System:
(I-A = Low Grade, intracompartmental, No Metastases);
(I-B = Low Grade, extracompartment, No Metastases);
(II-A = High Grade, intracompartmental, No Metastases);
(II-B = High Grade, extracompartment, No Metastases);
(III = Any Grade, Distant Metastases).
Orthopaedic Knowledge Update: Musculoskeletal Tumors. Menendez LR (Editor). Published by American Academy of Orthopaedic Surgeon, Rosemont, IL. Copyright 2002
AJCC Cancer Staging Manual, ed. 6. 2002. pp. 213-19.
Enneking WF. A system of staging musculoskeletal neoplasms. Clin Orthop Relat Res. 1986 Mar;(204):9-24.
PMID:3456859 (Link to Abstract)