Primary Site: Can we assume the primary site for "chordoma" is soft tissue if the bone is not stated to be involved?
Default the coding of the Primary Site field for chordomas to the bone where the tumor began in the body if the primary site is not clearly stated to be soft tissue. Bone is often the primary site for chordomas.
Based on advice from pathologist consultants: This is one of those situations where we can be quite comfortable with a default, in this case to bone, not soft tissue. Chordoma is a tumor arising in the nucleus pulposis, presumably from remnants of notochord - thus its exclusive origin is in the sacrococcygeal region, spheno-occipital region, and vertebral bodies, otherwise known collectively as the axial skeleton. Any "chordoma" in soft tissue (with no relationship to axial skeleton) is probably a myxoid chondrosarcoma or parachordoma (extremely rare).
Ambiguous Terminology/Reportability: How should the expressions "suspicious for but not diagnostic of" and "suspicious for the possibility of early invasive adenocarcinoma" be interpreted for reportability? Would the interpretation be different depending on the primary site?
For reportability, interpret "suspicious for but not diagnostic of" as NOT diagnostic of cancer.
The phrase "suspicious for the possibility of early invasive adenocarcinoma" may indicate that the case is in situ. If no further information is available, this is not reportable.
The site of the cancer diagnosis does not change the interpretation.
Reportability--Hematopoietic, NOS: Are the terms "thrombocytosis, NOS" and "thrombocythemia, NOS" non-reportable to SEER? See discussion.
Our understanding from SEER about how to classify these types of clinical impressions for the 2001 and later reportable blood diseases is as follows: If we cannot prove that it is malignant, then we should be conservative and exclude the case for reporting to SEER.
For cases diagnosed prior to 1/1/2010:The terms "thrombocytosis, NOS" and "thrombocythemia, NOS" are not reportable to SEER.
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.
EOD-Extension/EOD-Lymph Nodes--Rectosigmoid: How do you code these fields for a scan-based clinically staged T3 N1 rectosigmoid primary in a patient who received chemotherapy and radiation prior to a resection that demonstrated invasion only into the muscularis and no positive lymph nodes?
For cases diagnosed 1998-2003:
Use the best information available, in this case, the clinical staging, to code EOD. Code the EOD-Extension field to 40 [Invasion through muscularis propria or muscularis, NOS] and the EOD Lymph Node field to 3 [Regional lymph node(s) NOS] because the case had a clinical stage of T3 N1. EOD is coded using the most extensive clinical or pathologic stage.
Histology (Pre-2007)--Colon: What code is used to represent the histology "Adenocarcinoma, intestinal type?" See Description.
The code 8144/3 is not valid for colon primaries. Should we code these as 8140/3 [Adenocarcinoma, NOS] or over-ride the error message?
For tumors diagnosed prior to 2007:
Code adenocarcinoma, intestinal type of the colon 8140 [Adenocarcinoma, NOS]. Do not use code 8144 for intestinal type adenocarcinoma in the colon.
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.
Primary site: How is this field coded for a malignant spindle cell neoplasm in a subcutaneous mass of the right knee? See Description.
The pathology report says: Right knee tumor:
A. discrete subcutaneous mass 3.5x5.2x1.4 cm malignant spindle cell neoplasm (see Comment)
B. A focus of subcutaneous malignant neoplasm is identified in the superior resection margin.
C.All other margins are clear.
The comment mentions that the specimen has been sent to Mayo Clinic and the Mayo clinic consult says, "we still believe that the diagnosis of spindle cell carcinoma is correct. Obviously the differential diagnosis involves melanoma and sarcoma also. The results of the immunoperoxidase stains strongly support the prior diagnosis of a carcinoma."
Code the site to C49.2 [Connective, subcutaneous and other soft tissues of lower limb and hip]. The site is a subcutaneous mass. C49 with 8032/3 will not be impossible following the next updates to the SEER edits.
Laterality/Multiple Primaries (Pre-2007)--Ovary: Are ovarian primaries with bilateral involvement always coded to laterality 4 (bilateral)? See Description.
Example: "Right ovary with mass replacing majority of ovarian tissue consistent with serous adenoca. Lt ovary with foci of adenoca." No specific statement of primary. Can we assume that the malignancy originated in the right ovary since it is more extensively involved or should laterality be coded 4 because both ovaries have tumor?
For tumors diagnosed prior to 2007:
If one ovary is listed as the primary site, code laterality to that ovary. The example above is one of those times when you would code to the single ovary. The issue of one or both ovaries being involved is handled in staging.
Abstract the example above as a single primary with code 1 [Right] for laterality.
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--Lung: Do we ignore pericardial effusion seen on a CXR if a subsequent lobectomy reveals only a localized tumor? See discussion.
Note 6 in the lung EOD scheme instructs us to assume that a pleural effusion is negative if a resection is done. Does this also apply to a pericardial effusion? For example, if a pericardial effusion is seen on CXR, and a subsequent lobectomy reveals only a localized tumor, should the effusion be ignored?
For cases diagnosed 1998-2003: Ignore pericardial effusion which is negative for tumor. Assume that a pericardial effusion is negative if a resection is done and the tumor is pathologically confirmed to be localized.
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.
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