Dedifferentiated parosteal osteosarcoma

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Wold-LE; Unni-KK; Beabout-JW; Sim-FH; Dahlin-DC J-Bone-Joint-Surg-Am. 1984 Jan; 66(1): 53-9 Parosteal osteosarcoma is an uncommon malignant tumor of bone, and in a review of Mayo Clinic records we identified eleven cases of so-called dedifferentiated parosteal osteosarcoma. Ten of the eleven patients had had a long history of treatment for multiple recurrences of the tumor as a low-grade parosteal osteosarcoma and then for a definite recurrence as a high-grade undifferentiated osteosarcoma. The prognosis in this group of patients was similar to that in patients with conventional osteosarcoma.