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Enneking staging system

The Enneking staging system is used for staging of musculoskeletal sarcomas and is based on three criteria: histological tumor grade, the site (extent) of the tumor, and the presence of regional or distant metastases. The size of the tumor is not used for staging. Lymph node metastases are not taken into account per se; they do, however, affect the metastasis component when present. Clinical, radiological and histological data can be used for determining the value of each component.

The system should not be used for staging of nonmesenchymal tumors, such as lymphomas or Ewing sarcoma.

The following definitions are used in the Enneking staging system.

Tumor grade
G0 - benign lesion
G1 - low grade malignant lesion
G2 - high grade malignant lesion

Tumor site/extent
T0 - benign lesion confined within its true capsule, intracompartmental
T1 - aggressive benign or malignant intracompartmental lesion
T2 - extracompartmental lesion (a lesion breaching periosteum, joint cartilage, joint capsule, or fascia)
(Compartment is defined as a space limited by its natural anatomic boundaries. Examples include any individual bone, a joint space, or a muscular compartment enclosed in a fascia. Some regions are extracompartmental by definition. These include, for instance, popliteal and antecubital fossae, the groin, and paraspinal regions.)

Metastasis
M0 - no regional or distant metastases present
M1 - any regional or distant metastases, including skip lesions and lymph node metastases

Enneking staging system for benign tumors
1LatentG0T0M0
2ActiveG0T0M0
3AggressiveG0T1 or T2M0 or M1

Under the Enneking staging system benign tumors are divided into three groups: latent, active, and aggressive. Latent tumors are usually discovered incidentally. They have reached their non-growth stage by the time of discovery. Active tumors are histologically benign slow growing neoplasms that may cause mild symptoms. They grow steadily over a prolonged period of time. Aggressive tumors, despite being histologically benign, are locally invasive and may metastasize.

Enneking staging system for malignant tumors
IALow grade, intracompartmentalG1T1M0
IBLow grade, extracompartmentalG1T2M0
IIAHigh grade, intracompartmentalG2T1M0
IIBHigh grade, extracompartmentalG2T2M0
IIILow grade or high grade, with regional or distant metastasesG1 or G2T1 or T2M1

Malignant musculoskeletal tumors are divided into three stages. Stages I and II are further subclassified into A and B, depending on tumor grade.

References:
  1. W.F. Enneking, S.S. Spanier, M.A. Goodman. Current concepts review. The surgical staging of musculoskeletal sarcoma. J Bone Joint Surg Am. 1980, 62:1027-1030.


Last updated: May 3, 2012, 11:09 am EST

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