Primary site--Unknown & ill-defined site/Kidney: How should this field be coded when humeral metastases are compatible with renal cell carcinoma pathologically, no kidney lesion is found clinically and the physician's signout diagnosis is "no primary found, as of now unknown"? See Description.
Path states "biopsy of humerus, mets sarcomatoid carcinoma consistent with renal cell carcinoma." Material was sent to Mayo Clinic for consult & they state "with focus of clear cells, agree that a likely primary is renal cell carcinoma." Abdominal CT showed no abnormality in kidneys. When the registrar abstracted the case she spoke to the managing physician who told her that "no specific site was found and it was, as of now, unknown." This was stated about three months after dx. Can we code as a renal primary based on pathologic information or should we code unknown based on CT and physician's statement?
Code this case to C64.9 [Kidney, NOS].
ICD-O-3 rule H states that the topography code attached to a morphology term may be used when the topographic site is not given in the diagnosis. Topography code C64.9 is attached to morphology code 8312/3 [Renal cell carcinoma] in ICD-O-3.
EOD-Extension--Colon: How is this field coded for an appendical primary when the appendix has ruptured and intrapentoneal fluid is positive?
For cases diagnosed 1998-2003: Code EOD extension as 85 [Metastasis]. Positive intraperitoneal fluid is equivalent to distant metastasis (implantation) for colon, including appendix, primaries.
Multiple Primaries (Pre-2007): Is a small bowel carcinoid diagnosed 10 years after the diagnosis of metastatic carcinoid of unknown primary site a new primary or a new recurrence? See Description.
A patient was diagnosed in 1991 with metastatic carcinoid to liver-no primary found. In 2001, the patient is diagnosed with small bowel carcinoid at another hospital. Hospital 2 has no other information.
For tumors diagnosed prior to 2007:
Code as two primaries unless there is a physician's statement that the liver lesion is metastatic from the later small bowel carcinoid. Without such a statement regarding lesions 10 years apart, do not make an assumption that one is metastatic from the other.
For tumors diagnosed 2007 or later, refer to the MP/H rules. If there are still questions about how this type of tumor should be coded, submit a new question to SINQ and include the difficulties you are encountering in applying the MP/H rules.
EOD-Extension--Corpus Uteri: How is this field coded for a stage III A endometrial primary with positive pelvic washings, involvement of the omental serosa, and negative lymph nodes?
For cases diagnosed 1998-2003: Code EOD-extension as 85 [Metastasis]. According to our TNM consultant, Omental metastasis is M1, Stage IVB [EOD 85].
EOD-Regional Lymph Nodes--Breast: Are subpectoral nodes the same as interpectoral nodes and, therefore, regional for breast primaries?
Subpectoral lymph nodes are regional nodes for breast primaries. Subpectoral is the term generally used to describe the placement of a prosthesis during reconstruction (under/behind the pectoralis major muscle). That is the same location for interpectoral, or Rotter's, nodes.
Primary Site/EOD-Extension--Kaposi Sarcoma: How are these fields coded for localized disease described as "Nodal Kaposi Sarcoma" found on inguinal node biopsy only?
Code the site of involvement as the primary site when no other involvement is documented. For the case above, code C774 [inguinal lymph node] as primary site.
For cases diagnosed 1998-2003: Code EOD-extension as 13 [Visceral].
Primary Site/Histology--CLL/SLL: How should these fields be coded when the pathological diagnosis of chronic lymphocytic leukemia/small lymphocytic lymphoma is made on bone marrow biopsy only but scans show lymphadenopathy? See Description.
What histology would we give these two examples?
1. Bone marrow bx: CLL/SLL. CT chest/abdomen: Mediastinal and retroperitoneal adenopathy.
2. Bone marrow bx: CLL/SLL. CT chest/abdomen: Mediastinal and retroperitoneal adenopathy suspicious for lymphoma.
For cases diagnosed prior to 1/1/2010:If a lymph node or other solid tissue is involved initially, code to SLL. For lymphoma, any mention of lymph nodes is indicative of involvement. Involvement does not have to be proven pathologically in order to code to Small Lymphocytic Lymphoma (SLL). Code both of the examples to SLL.
For cases diagnosed 2010 forward, refer to the Hematopoietic and Lymphoid Neoplasm Case Reportability and Coding Manual and the Hematopoietic Database (Hematopoietic DB) provided by SEER on its website to research your question. If those resources do not adequately address your issue, submit a new question to SINQ.
Reportability--Ovary: Is a Stage IIIC serous borderline tumor (micropapillary type) of the ovary diagnosed in 2003 reportable?
Serous borderline tumor of the ovary diagnosed in 2003 is not reportable to SEER. The behavior code is /1 in ICD-O-3. The high stage does not make this borderline tumor reportable.
Multiple Primaries (Pre-2007)/Histology (Pre-2007)--Breast: Would the simultaneously occurring histologies of "high grade ductal carcinoma in situ with micro invasion" and "keratinizing squamous cell carcinoma" be coded as two primaries or as a single primary when the pathologist is not clear whether two separate tumor masses exist?
For tumors diagnosed prior to 2007:
Code as two primaries, assuming the tumors are separate and the margins are clear/negative. Code 8071/3 [Invasive squamous cell ca, keratinizing] and 8500/3 [Ductal carcinoma, "microinvasive"].
For tumors diagnosed 2007 or later, refer to the MP/H rules. If there are still questions about how this type of tumor should be coded, submit a new question to SINQ and include the difficulties you are encountering in applying the MP/H rules.
First Course Treatment/Hormone Therapy--Thyroid: Is hormone replacement therapy such as levothyroxine (Synthroid) for thyroid carcinoma coded as first course of treatment? See Discussion.
Examples:
Patient was admitted for thyroidectomy with a diagnosis of probable thyroid cancer. Patient's history stated that patient received work-up for hypothyroidism and was found to have thyroid nodule. Fine needle aspirate suggested carcinoma. Patient's medications included Cytomel and Synthroid.
Patient was given levothyroxine after thyroidectomy for medullary thyroid carcinoma.
Updated December 2025
Do not code levothyroxine given to treat hypothyroidism or as cancer treatment for medullary carcinoma when given as replacement therapy and not as thyroid stimulating hormone (TSH) suppression therapy. Thyroid hormone therapy is generally coded as treatment for follicular, papillary, and oncocytic thyroid carcinomas.
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