SITE SPECIFIC DATA ITEMS (SSDI)/ GRADE

Description

The ICD-O-3 assigned topography codes for the peripheral nerve and autonomic nervous systems tumors (C47) and the connective, subcutaneous and other soft tissues (C49) primary sites are based on transverse or horizontal planes. The AJCC Staging System Soft Tissue Sarcoma of the Trunk and Extremities, and Soft Tissue Sarcoma of the Abdomen and Thoracic Visceral Organs base the eligible sites as either external structures or internal viscera. For example, * C493 axilla is an external site using the AJCC Staging System Soft Tissue Sarcoma of the Trunk and Extremities * C493 axillary artery is an internal site using the AJCC Staging System Soft Tissue Sarcoma of the Abdomen and Thoracic Visceral Organs * C475 sacrococcygeal region is a large area that may be either external or internal * Need to determine the exact area involved to assign the correct chapter * C475 external area of sacrococcygeal region uses the AJCC Staging System Soft Tissue Sarcoma of the Trunk and Extremities * C475 intrapelvic area of sacrococcygeal region uses the AJCC Staging System Soft Tissue Sarcoma of the Abdomen and Thoracic Visceral Organs To develop a software algorithm that can be used to send the registrar to the correct system/schema, this schema discriminator was developed. The schema discriminator is based on determining whether the structure involved is part of the external structures or the internal viscera. This is accomplished by * Terms in ICD-O-3 topography codes sorted appropriately by the physician experts when possible * Instructions on what to do when terms are not specific enough to be assigned as external structures or internal viscera * Without additional information, these may not be staged, for example C475 pelvis * With additional information, these may be determined to be external structures or internal viscera * In addition to the topography codes and terms, there is also an option of “External sites, NOS” and “Internal sites, NOS” for registrars to use to assign the schema discriminator. Registrars may need to use additional information, including physician staging, to choose the appropriate schema discriminator

Notes

**Note:** **Schema discriminator for C473, C475, C493-C495** * A schema discriminator is used to discriminate for peripheral nerve tumors (C473, C475) and connective tissue tumors (C493, C494, C495) for the subsite in which the tumor arose.