An intracapsular margin is obtained when the surgical dissection extends through the reactive zone and the capsule or pseudocapsule into the tumor itself. A marginal margin describes a plane of dissection through the reactive zone just outside the capsule or pseudocapsule. A wide margin is achieved when the dissection plane is through normal tissue outside the reactive zone; thus, the tumor and its pseudocapsule are excised along with an intact “cuff” of normal tissue. A radical margin describes removal of the tumor and the entire compartment (the entire bone or muscle compartment) that contains it. Although marginal, wide, or radical margins may all be free of tumor cells, the marginal margin, because of the closer proximity of the surgical margin to the tumor, is more likely to leave behind microscopic fragments of tumor and thus lead to local recurrence. Similarly, a wide margin of less than 1 cm, despite removal of a cuff of normal tissue, usually still has a higher risk for leaving residual tumor cells than does a radical procedure.

The term contaminated margin refers to a recognized intraoperative violation of the lesion, followed by closure and subsequent adjustment of the plane of dissection. For example, a contaminated wide excision indicates that the tumor was inadvertently entered during the tumor removal, the exposed tissues were contaminated by leakage from the tumor, the opening was closed, and the contaminated tissues were excised to obtain a wide margin.

The adequacy of the surgical margin is estimated by gross and microscopic examination of the excised specimen. Gross inspection is particularly important in distinguishing whether a wide margin or a radical margin has been obtained, because the microscopic appearance of each is free of tumor cells.