Reportability/Behavior Code--Soft Tissue: Is a final diagnosis of a forearm mass diagnosed as "Angiomatoid malignant fibrous histiocytoma [see note]" reportable? The NOTE reads "Angiomatoid malignant fibrous histiocytoma is a low grade borderline lesion with a tendency for local recurrence, but a very low potential for distant metastases." Is behavior /1 or /3?
Angiomatoid malignant fibrous histiocytoma is reportable with a behavior code of /3 according to ICD-O-3. The Final Diagnosis takes precedence over the "note."
EOD/Summary Stage--Eye: How is stage coded for a patient with extranodal non-Hodgkin lymphoma involving bilateral choroids (single focus, both sites) and no lymph node involvement? Since the eyes are a paired site, is this two separate extranodal sites? If so, there are no Summary Stage or EOD tumor codes that best fit this scenario.
Assign as Stage IV as recommended by our expert hematological oncologist. This is a rare occurrence and this type of presentation does not fit the definition of intraocular extension. Stage IV is probably the best stage for this type of presentation, since there are two extranodal organs involved, even though they involve a bilateral site.
Laterality--Heme & Lymphoid Neoplasms: Is laterality coded to 0 [not paired] for all lymphoma cases including paired sites (e.g., breast, lung)?
Updated May 2026
Laterality coding for lymphomas is based on the primary site not histology. Laterality describes the side of a paired organ or side of the body on which the reportable tumor originated. Determine whether laterality should be coded for each primary.
Laterality coding instructions are located in the SEER Program Coding and Staging Manual.
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.
Behavior--Breast: How is behavior coded when a biopsy shows in situ carcinoma with a focus suspicious for invasion and a subsequent excision/resection shows only in situ carcinoma?
Code this case as in situ. The specimen from the excision/resection is the more reliable source for determining behavior, compared to a biopsy, especially in this case where the behavior is ambiguous on the biopsy.
Reportability/Histology--Head & Neck: Is carcinoma cuniculatum of the hard palate diagnosed in 2017 reportable? Was this rare variant of squamous cell carcinoma (SCC) missed in Casefinding? If reportable, what is the histology code?
Carcinoma cuniculatum of the hard palate is reportable. Code to SCC, NOS (8070/3). Use text fields to record the details.
While WHO recognizes carcinoma cuniculatum to be a new variant of oral cancer, it has not proposed a new ICD-O code for this neoplasm.
Primary site--Lung: What is the code for primary site if a small cell carcinoma presents as mediastinal masses?
Code the primary site to main bronchus [C340].
Primary small cell carcinoma in the thymus/mediastinum is rare. A bronchial lesion with extension into the mediastinum is much more likely. In a case like this, it is difficult to be sure exactly where the tumor arose, however, it is recommended the default site be the main bronchus when there is no information to the contrary.
Reportability/Histology--Endometrium: Is endometrial hyperplasia with atypia equivalent to atypical hyperplasia of the endometrium (8380/2) and thus reportable?
Endometrial hyperplasia with atypia is equivalent to atypical hyperplasia of the endometrium (8380/2) and thus reportable for cases diagnosed 2021 and later. Our expert pathologist consultant confirmed this for us.
Reportability/Histology--Pancreas: According to SINQ 20140058, solid pseudopapillary neoplasm of the pancreas is reportable (as of 2014). However, per ICD-O-3.2, this histology is not reportable until 2021+. Please clarify which is correct and clearly state the timeframe that it was reportable or not reportable.
Solid pseudopapillary neoplasm of the pancreas is reportable for cases diagnosed in 2014 and later. Report solid pseudopapillary neoplasm of the pancreas (8452/3) as the guidance in SINQ 20140058 is still in effect.
The 4th and 5th editions of the WHO Classification of Tumors of the digestive system define solid pseudopapillary neoplasm of the pancreas as a low-grade malignant pancreatic tumor.
Reportability: Is a "pleomorphic hyalinizing angiectatic tumor of soft parts (PHAT)" reportable if the case has a TNM stage assigned and is stated by the pathologist to be a rare intermediate grade sarcoma?
Pleomorphic hyalinizing angiectatic tumors of the soft parts are not reportable.
According to our pathologist consultant, PHAT is a borderline malignancy (/1). While the true nature of these tumors is under debate (reactive vs. neoplastic), so far none have metastasized.
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