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The resection pathology report final diagnosis indicates this is both mixed mucinous and non-mucinous with a lepidic predominant component. The pathologist notes this is “Lepidic: 75%. Acinar: 25%.”  The percentage of the mucinous component is not documented.

Rule H1, Note 1, states “When mucinous carcinoma is mixed with another histology, such as adenocarcinoma and mucinous carcinoma, code mucinous ONLY when mucinous is documented to be greater than 50% of the tumor.” While mixed invasive mucinous and non-mucinous carcinoma is included in Table 2 (Combination/Mixed Histology Codes) without a required percentage, it is unclear whether one should move past Rule H7 and use Rule H8 to code this combination histology code. Rule H7 would instruct one to code the histology to lepidic adenocarcinoma (adenocarcinoma, lepidic predominant) based on the percentage of the lepidic component in the tumor. However, this does not address the mixed mucinous and non-mucinous diagnosis. Which H Rule and histology apply to this case?

The case in question represents an adenocarcinoma with neuroendocrine differentiation that arises in the absence of androgen-deprivation therapy. A 2023 journal article states, “We show that amphicrine prostate cancer is a unique entity and differs in clinical and molecular features from high-grade neuroendocrine carcinomas of the prostate. Our study highlights the need to recognize AMPC as a unique molecularly defined subgroup of prostate cancer.”

Should we be coding this with histology 8140 (Adenocarcinoma, NOS) because we have no specific code for an amphicrine carcinoma? Should we code this as 8045 (Mixed small cell carcinoma) because this is possibly the only way to capture both the adenocarcinoma and neuroendocrine components in a patient without previous treatment?

Our concern about using histology code 8574 (Adenocarcinoma with neuroendocrine differentiation) is that, while a valid histology code, this might confound the data if researchers are trying to separate the truly treatment-related tumors from other histologies captured under 8574.

Patient was diagnosed in September 2022 via excision of a 12 cm pelvic mass with final diagnosis of Myofibroblastoma with sarcomatous transformation.

Diagnosis comment states, “Most of the tumor is composed of conventional features of myofibroblastoma. However, a focal area demonstrates increased cellularity, fascicular growth and increased mitotic activity (up to 11 per 10 hpf), consistent with sarcomatous transformation (morphologically low to intermediate grade).”

Is this sarcomatous transformation describing a malignant transformation from an otherwise benign histology? If so, how should histology be coded in this case?

While SEER*Rx does indicate infliximab should be coded as biological response modifier (BRM)/Immunotherapy, the manufacturer website for this medication indicates it is given for: Crohn’s disease, ulcerative colitis, rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, and plaque psoriasis. In addition, SEER*Rx does not indicate which primary sites this treatment may be given for. If it is indeed cancer directed treatment, can the typical primary sites be added for clarity?

Case example: Patient is diagnosed with colorectal cancer and also has an existing diagnosis of Crohn’s disease; received surgery and FOLFOX6, as well as infliximab. There was no statement of what disease the infliximab was given to treat.  

This patient had serosal involvement and the pathologist and managing physician staged this as pT4a disease.  This extension seems best captured by EOD Primary Tumor code 500.  Additionally, the patient had discontinuous metastatic involvement of the peritoneum, and this was staged by the pathologist and managing physician as pM1b (Intraperitoneal metastasis only, including peritoneal mucinous deposits containing tumor cells).  Although this peritoneal involvement was present in the right lower quadrant, it was staged as distant metastatic disease and not as part of the primary tumor category. However, currently EOD Primary Tumor code 600 would seem to apply since the peritoneal tumor was in the right lower quadrant.  Code 600 is defined as mucinous tumors with peritoneal involvement confined within right lower quadrant.  This EOD Primary Tumor code and the physician’s M category assignment do not align; the physician has staged this as distant metastasis (M category, not the T category).  Should the peritoneal metastasis (even limited to the right lower quadrant) be included in the EOD Mets field and not in the EOD Primary Tumor field?  In other words, should the peritoneal involvement included in EOD Primary Tumor code 600 be reclassified in EOD Mets code 30 (Intraperitoneal metastasis (peritoneal carcinomatosis) WITH or WITHOUT peritoneal mucinous deposits containing tumor cells)?

The patient was initially diagnosed with invasive mammary carcinoma of the right breast in 2018, treated with lumpectomy, sentinel node biopsy, radiation, and hormones. Hormones were discontinued early due to dysfunctional uterine bleeding.

Disease History

2018 - Lymphomatoid papulosis (non-reportable)

2020 - Transform to CTCL (and called Mycosis Fungoides specifically) (CTCL/MF same primary)

2021 - Transform to CTCL with large cell transformation