Reportability--Heme & Lymphoid Neoplasms: Is the term "thrombocytopenia" equivalent to the term "refractory thrombocytopenia" and should be a subsequent primary if it follows a treated diagnosis of pancreatic cancer?
Updated May 2026
Thrombocytopenia NOS is not a reportable diagnosis for any diagnosis year. Thrombocytopenia and Refractory Thrombocytopenia are not the same disease.
Thrombocytopenia is caused by a decreased number of platelets in the blood. Non-malignant causes include disseminated intravascular coagulation (DIC), drug-induced non-immune thrombocytopenia, drug-induced immune thrombocytopenia, hypersplenism, immune thrombocytopenic purpura (ITP), thrombotic thrombocytopenic purpura, and infections of the bone marrow.
EOD-Extension--Breast: If the pathology report states "infiltrating duct carcinoma...measuring 7mm in diameter...focal areas of intraductal carcinoma," do we code this field to 14 [Invasive and in situ components present, size of entire tumor coded in Tumor Size and in situ described as minimal] or to 16 [Invasive and in situ components present, size of entire tumor coded in Tumor Size and proportions of in situ and invasive not known]?
For cases diagnosed 1998-2003: If 7mm is the measurement of the infiltrating duct portion of this cancer, assign extension code 13 [Invasive and in situ components present, size of invasive component stated and coded in Tumor Size].
If 7mm is the size of the whole malignancy and the size of the invasive portion cannot be determined, assign extension code 14 [Invasive and in situ components present, size of entire tumor coded in Tumor Size (size of invasive component not stated) and in situ described as minimal (less than 25%)]. "Focal areas of in situ carcinoma" qualifies as minimal.
MP/H Rules/Histology--Colon: The final diagnosis on a path report for a colon specimen says: Is a colon specimen final diagnosis of carcinoma in situ in a serrated adenoma coded to 8010/2, 8210/2 or 8213/2?
For cases diagnosed 2007 or later, code the histology as 8213/2 [carcinoma in situ in a serrated adenoma].
The steps used to arrive at this decision are:
: Apply ICD-O-3 rule F (Matrix principle) and assign the behavior code /2 when the behavior assigned by the pathologist differs from the usual behavior as given in the ICD-O-3.
: Open the Multiple Primary and Histology Coding Rules Manual. Choose one of the three formats (i.e., flowchart, matrix or text) and go to the Colon Histology rules.
: Start at the SINGLE TUMOR module, Rule H1. The rules are intended to be reviewed in consecutive order within a module. Stop at rule H4. Code the histology as 8213/2.
Note: The histology 8213 (adenocarcinoma in serrated adenoma) will be added to rule H4 in the next revision.
Residence at dx: After living elsewhere (Florida) and traveling around the country in an RV with his spouse, is a patient a resident of this area for either primary if he was diagnosed with his first primary less than a month after arriving in the area and a second primary more than a year after parking his RV here?
Use the patient's usual residence to determine residency. If the usual residence is not known or the information is not available, use the residence the patient specifies at the time of diagnosis. The SEER rules for determining "usual residence" match the rules used by the US Census Bureau.
First Course Cancer-Directed Treatment--Bladder: How should Mitomycin-C instillation for bladder cancer be coded?
Code the instillation of Mitomycin-C into the bladder for a bladder primary in both the Chemotherapy and Surgery to Primary Site fields. Code the Chemotherapy field to 02 [Single-agent chemotherapy administered as first course therapy]. Mitomycin-C is listed in SEER book 8 as a chemotherapeutic drug, specifically an alkylating agent.
Also, code the Surgery of Primary Site field to 15 [intravesical therapy]. Code the surgical procedure as well as the type of drug (chemotherapy in this case).
EOD-Extension--Lung: How do you code extension for a lung tumor described on bronchoscopy as "obstructing the RUL and intruding into the right bronchus intermedius. Small tumor nodules distally in midline of anterior trachea wall"?
For cases diagnosed 1998-2003:
Code the EOD-Extension field to 85 [Metastasis] because the tumor nodules are discontinuous from the primary tumor.
Reason No Cancer-Directed Surgery--Hematopoietic, NOS: Is this field always coded to 1 [not performed, not part of first course] for leukemias & other hematopoietic diseases?
For cases diagnosed 2003 and later: For sites where "Surgery of the primary site" is coded 00 or 98 (hematopoietic included), Reason for No Surgery of Primary Site should be coded as 1 [Surgery of the primary site not performed because it was not part of the planned first course of treatment]. On rare occasions, there may be surgery to the primary site for a hematopoietic disease, such as an excisional biopsy of a myeloid sarcoma. Refer to the "Abstracting and Coding Guide for the Hematopoietic Diseases" for cell-type-specific treatment information.
Primary Site--Heme & Lymphoid Neoplasms: What primary site code should be assigned and what rule justifies that code?
Scenario: Pleural effusion, underwent thoracentesis. Pleural fluid unexpectedly showed Large B-Cell Lymphoma. Extensive workup including CT & PET was done and all findings were within normal limits. No evidence of lymphoma was seen and no palpable adenopathy was found. The only indication of lymphoma was the malignant pleural effusion.
Code to pleura, C384.
Per the Hematopoietic database, Diffuse Large B-Cell Lymphoma can originate in the pleural cavity.
EOD 2018/Prostate Pathologic Extension--Prostate: Is a pathology report from a prostate biopsy/transurethral resection of the prostate that states "with intraductal spread" extraprostatic/extracapsular extension or localized?
Code as a localized, intracapsular tumor as ductal carcinoma in situ does not invade. Intraductal spread is describing the neoplasm spreading through the acinar/ductal cells in the prostate specimen. It is an in-situ type of spread and not invasive but almost always presents with an invasive tumor.
2024 SEER Manual/Primary Site--Breast: Is Primary Site coded as C504 or C501 based on the Solid Tumor Rules and the SEER Manual Breast Coding Guidelines? The pathology report reads "Right Breast 10:00 1 cm from the nipple."
Codes C502-C505 take priority over code C501. The description for C501 in the Solid Tumor Rules has "Area extending 1 cm around areolar complex."
Assign Primary Site code C504 based on the location in the upper outer quadrant of the right breast, 10 o’clock, as opposed to code C501, around the areolar complex. The 2024 SEER Manual Breast Coding Guidelines advise that C502 - C505 are generally preferred over C501 when there is no other way to determine the subsite.
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