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Code cutanteous leiomyosarcoma to skin. Leiomyosarcoma can originate in the smooth muscle of the dermis. The WHO classification designates this as cutaneous leiomyosarcoma. The major portion of the tumor is in the dermis, although subcutaneous extension is present in some cases.

Updated May 2026

Unless there are scans showing involvement of a lymph node or tissue other than the chest wall, the histology should be coded myeloid sarcoma [9930/3] and the primary site to C493 [soft tissue of chest wall]. Override the edit.

Per the Abstractor Notes section in Heme DB, for myeloid sarcoma [9930/3] the most frequently affected sites are skin, lymph nodes, gastrointestinal tract, soft tissue, and testis.

For cases diagnosed 2010 and forward, access the Hematopoietic Database at http://seer.cancer.gov/seertools/hemelymph..

Code the primary site to the involved lymph nodes [C770-C779]. Per Rule PH 8, it indicates you are to code the primary site to the site of origin when lymph node(s) or lymph node region(s), tissue(s) or organs are involved. Note 2 further states that the bone marrow may or may not be involved. If the bone marrow is involved, code this information in the CS Extension field.

Per the Abstractor Notes section in the Heme DB, this is a systemic disease with widespread lymph node involvement as well as involvement of the peripheral blood. In addition, systemic involvement of extranodal sites (including lung) are often involved.

SEER*Educate provides training on how to use the Heme Manual and DB. If you are unsure how to arrive at the answer in this SINQ question, refer to SEER*Educate to practice coding hematopoietic and lymphoid neoplasms. Review the step-by-step instructions provided for each case scenario to learn how to use the application and manual to arrive at the answer provided. https://educate.fhcrc.org/LandingPage.aspx.

For cases diagnosed 2010 and forward, access the Hematopoietic Database at http://seer.cancer.gov/seertools/hemelymph.

Code the primary site to C421 [bone marrow]. Our hematopoietic specialty physicians state that involvement of peripheral blood is equivalent to bone marrow involvement because the marrow produces blood. In the absence of any other involvement, per Module 7 (Coding primary sites for lymphomas) Rule PH26, it states to code the primary site to bone marrow when the only involvement is bone marrow.

SEER*Educate provides training on how to use the Heme Manual and DB. If you are unsure how to arrive at the answer in this SINQ question, refer to SEER*Educate to practice coding hematopoietic and lymphoid neoplasms. Review the step-by-step instructions provided for each case scenario to learn how to use the application and manual to arrive at the answer provided. https://educate.fhcrc.org/LandingPage.aspx.

Code the primary site as skin of breast when skin of breast is documented as the site of origin.

According to the WHO classification of soft tissue tumors, the majority of angiosarcomas "develop as cutaneous tumors...less than one quarter present as a deep soft tissue mass."

Updated May 2026

In the Abstractor Notes section in the Heme DB, it indicates the primary site may differ for LCH in the solitary disease and multisystem disease. This patient has multisystem disease with involvement of the bone, liver, spleen and retroperitoneum. The most common sites for multisystem involvement include three of the four above sites (bone, liver, and spleen).

Determine the primary site based on the knowledge of the usual sites of involvement for this disease, the actual sites of involvement for the case presented, and identifying which sites of involvement are likely metastatic and which are the potential primary sites. There are two potential primary sites of involvement: the bone and the retroperitoneum. Bone is a common site of involvement for LCH while the retroperitoneum is not. Code the primary site to C419 [bone, NOS] because multiple bones are involved for this patient and bone is the most common site for LCH based on the documentation in the Abstractor Notes.

The spleen and liver are typically not primary sites for this disease process. They become involved when there is multisystem involvement because they filter the blood. They are typically sites of metastatic involvement.

The Abstractor notes also indicate that if it's not possible to determine primary site for LCH, default to Bone, NOS (C419)

Use Rule M2. Abstract as a single primary when there is a single histology.

When you have questions about how to code the primary site, start with the abstractor notes. If the answer isn't found there go to Module 7 (a specific module to help code primary site for lymphomas).

The abstractor notes for DLBCL in this case do not provide information you can use for this case. Go to Module 7 in the PH rules.

Use Rule PH25 Code the primary site to the organ when lymphoma is present in an organ and that organ’s regional lymph nodes. Code the primary site to colon (organ and regional lymph nodes involved). The fallopian tube is secondary involvement. As is common with lymphomas, there can be more than one organ involved. You can differentiate the primary site from the secondary site(s) because of the large colon mass with regional lymph node involvement.

Abstract as a new primary per rule M10, as the subsequent tumors are not limited to the bladder. Code the primary site to C689, per Instructions for Coding Primary Site, #4: "Code Urinary System NOS C689 when there are multiple non-contiguous tumors in multiple organs within the urinary system", and following Note: "The physician subject matter experts (SME) discussed the issue of coding primary site for multifocal/multicentric urinary tract carcinoma. Although the SMEs understood and acknowledged the importance of coding a specific primary site, there is no literature or criteria for determining the organ of origin for multiple tumors involving multiple urinary sites".