MP/H Rules/Histology--Corpus uteri: How should histology be coded and how many primaries should be accessioned for an endometrial primary in which curettings showed malignant mixed mullerian tumor (carcinosarcoma) but hysterectomy specimen showed endometrioid adencarcinoma? See Discussion.
Primary site/Histology--Head & Neck: How are these fields coded when the final diagnosis for a skull based mass is "neuroendocrine carcinoma" and the IHC studies are incompatible with a brain/spinal cord primary (ependymoma)? See Discussion.
Multiplicity Counter--Kidney, Renal Pelvis: How many times is this field updated after an invasive primary is originally diagnosed? Should subsequently diagnosed in situ tumors to be included in this field? See Discussion.
MP/H Rules/Primary site--Kidney, Renal Pelvis: Should the primary site be changed to C689 [Urinary system, NOS] for a primary renal pelvis tumor after additional tumors are found months later in different urinary sites (e.g., bladder or ureter) and the MP/H Rules indicate these are all the same primary? See Discussion.
Histology: How is this field coded for a perivascular epithelioid cell neoplasm (PEComa) of uncertain malignant potential that is malignant based on the presence of metastases? See Discussion.
Multiple primaries/Histology--Heme & Lymphoid Neoplasms: Is a 2010 diagnosis of ALK+ anaplastic T cell lymphoma following a 2008 diagnosis of follicular B cell lymphoma, grade 1 a new primary? If so, how is the histology coded? See Discussion.
Histology--Ovary: How is histology coded for an ovarian mucinous neoplasm of low malignant potential (borderline mucinous cystadenoma) that shows extensive intraepithelial carcinoma and focal microinvasion? See Discussion.
Reportability/Heme & Lymphoid Neoplasms--Hematopoietic, NOS: Is light chain disease reportable if it is treated with chemotherapy agents? See Discussion.