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Report Produced: 09/06/2025 03:00 AM

Report Question ID Question Discussion Answer Year
20130152 Primary site/Histology--Brain and CNS: How is the primary site and histology coded for a 2013 diagnosis of squamous cell carcinoma arising in a dermoid cyst of the third ventricle? See Discussion. Patient has a dermoid cyst of the third ventricle of the brain diagnosed in 1998. In 2013 the cyst was removed and was diagnosed as squamous cell carcinoma. An internet search revealed a journal article in the Journal or Neuro-Oncology that states, "Although rare, malignant transformation of intracranial epithelial cysts has a poor prognosis." The combination of site C715 [third ventricle, NOS] and histology 8070/3 [squamous cell carcinoma] fails SEER Edit IF 38_3: Primary site and Morphology Impossible. According to the literature, intracranial squamous cell carcinoma is very rare with most cases arising from a preexisting benign epidermoid cyst. The combination of C71_ and 8070/3 should be allowed. We will submit a request to have this edit revised. 2013
20041022 Primary site/Histology (Pre-2007)/Behavior: What is the correct site and histology/behavior for the following diagnosis: "mucinous cystadenoma of the appendix with perforation and pseudomyxoma peritonei." This was diagnosed at e-lap for a separate adenocarcinoma of the ascending colon.

For tumors diagnosed prior to 2007:

The appropriate code for mucinous cystadenoma of the appendix with perforation and pseudomyxoma peritonei is C18.1 8470/0. It is not reportable to SEER. According to our pathologist consultant, mucinous cystadenoma is a legitimate term for such appendiceal tumors. They may implant all over the peritoneum as pseudomyxoma peritonei, especially in the face of perforation, without being histologically malignant.

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.

 2004
20120041 Primary site/Heme & Lymphoid Neoplasms: How is the primary site coded if the patient presents with diffuse B cell lymphoma involving the nasopharynx and right maxillary sinus with bilateral cervical, right supraclavicular and axillary lymph nodes? See Discussion.

There is one mass in the nasopharynx and right maxillary sinus and the site of origin cannot be determined for this diffuse B-cell lymphoma. The patient also has bilateral cervical, right supraclavicular and axillary lymph nodes.

Should the primary site be coded per Module 7 Rule PH25 because regional nodes are involved or Rule PH22 because both regional and distant nodes are involved? If rule PH22 is used, what is the primary site?

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

Code the primary site to C119 [nasopharynx] per Rule PH25.

Per our subject matter expert, use Module 7 Rule PH25 to code the primary site to an organ (nasopharynx and maxillary sinus) because an organ(s) and its regional lymph nodes are involved. The distant lymph nodes are simply part of the staging (the lymphoma has progressed to another lymph node region).

Diffuse large B cell lymphoma originating in the oral cavity and maxillofacial region is rare, but documented. The most common sites for this rare neoplasm are Waldeyer ring, tonsils, nasopharynx, base of tongue, and palatine tonsil. There are also rare cases of diffuse large B cell lymphoma originating in the maxillary sinus. The percentage of cases arising in the nasopharynx is greater than those originating in the maxillary sinus.

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.

2012
20031140 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.

 2003
20140005 Primary site--Testis: In the absence of a specific statement that the patient's testicle(s) are descended, should the primary site for a testicular tumor be coded as C621 (Descended Testis) when the mass is palpable on physical exam or demonstrated on scrotal ultrasound? See discussion. It seems the non-specific Testis, NOS (C629) code is being over used. Many testis cases have no documentation of the patient's testicular descention. However, testicular tumors in adults are frequently detected by palpation or scrotal ultrasound. An undescended testis (a testis absent from the normal scrotal position) would be non-palpable or not amenable to imaging via a scrotal ultrasound. Unless the testicle is stated to be undescended, it is reasonable to code C621 for primary site. Reserve C629 for cases with minimal or conflicting information. 2014
20031130 Primary site--Melanoma: Should melanoma of the nipple be coded to C50.0 [Nipple] or C44.5 [Skin of the trunk]? Code to C44.5 [skin of trunk]. External melanoma is an epidermal malignancy, beginning in melanocytes in the basal layer of the epidermis. C50.0 excludes skin of breast. 2003
20120029 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.

 2012
20130008 Primary site--Kidney, renal pelvis: Should primary site be coded C809 [unknown] or C649 [kidney] when a patient is diagnosed with renal cell carcinoma in a transplanted kidney? Code the primary site to C649 [kidney]. Per the SEER Manual, code the site where the neoplasm originated. There are no separate instructions for coding primary site for transplanted organs. This patient's renal cell carcinoma originated in the kidney [C649]. 2013
20130147 Primary site--Heme & Lymphoid Neoplasms: What the primary site for a diagnosis of Langerhans cell histiocytosis with multifocal multisystem involvement of the skin, chest, CNS and thyroid, but no evidence of involvement on a bone scan?

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

Code the primary site to C809 [unknown].

Langerhans Cell Histiocytosis (LCH) includes three major groups:

  • Unifocal: Slowly progressing disease, involves one organ.

  • Multifocal unisystem: Involves several organs in one system.

  • Multifocal multisystem: Involves several organs in two or more systems.

    • When the disease is both multifocal and multisystem, code the primary site to unknown [C809] because there is no way to identify the origin of the neoplasm in this situation.

    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.

    		2013
    		20130206 Primary site--Heme & Lymphoid Neoplasms: What rule applies to code a primary site for a peripheral blood diagnosis of marginal zone lymphoma that has a positive flow cytometry/FISH analysis when no biopsies are performed, scans show no evidence of disease, exam indicates no lymph nodes are palpable and the physician's clinical diagnosis "marginal zone lymphoma, unspecified site, stage 1"? See Discussion.

    PE: No palpable lymph nodes.

    PET scan: No spleen or lymph node uptake; no uptake anywhere in the body.

    Peripheral blood and flow cytometry/FISH analysis diagnosis: Marginal zone lymphoma.

    No bone marrow or biopsy of any lymph nodes done. Doctor states "marginal zone lymphoma, unspecified site, stage 1."

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

    Per Rule PH27, code the primary site to C809 [unknown primary]. According to Rule PH27 one is to code the primary site to unknown primary site C809 when there is no evidence of lymphoma in lymph nodes AND the physician documents in the medical record that he/she suspects that the lymphoma originates in an organ(s) OR multiple organ involvement without any nodal involvement.

    If further workup is done and a primary site is determined, update the primary site for this case.

    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.

    		2013