#1: MP/H Rules
#2: Multiple primaries
#3: Brain and CNS
Source 1: 2007 MP/H Rules
Notes: Malignant Brain, M rules
MP/H Rules/Multiple primaries--Brain and CNS: How many primaries should be abstracted for a patient with a 2011 diagnosis of oligodendroglioma followed by biopsy of tumor which demonstrated progression in 2016 with pathology report Final Diagnosis indicating WHO grade III anaplastic astrocytoma? See Discussion.
The clinical documentation clearly identifies residual tumor after the 2011 craniotomy. Scans demonstrated slow enlargement of the tumor over the years, which resulted in a repeat craniotomy. The pathologist noted in the diagnosis comment section of the pathology report that
since the time of the patient's original diagnosis and the 2016 specimen, new WHO criteria for classifying infiltrating gliomas have been developed. Despite the morphologic features, the absence of 1p, 19q co-deletion precludes the classification of this glioma as an oligodendroglioma using current criteria. The combined histologic, immunophenotypic and molecular findings are consistent with the integrated diagnosis of Anaplastic Astrocytoma, IDH mutant, WHO Grade III.
Is this a single primary per MP/H Rule M3 (A single tumor is always a single primary), or an additional brain malignancy per MP/H Rule M8 (Tumors with ICD-O-3 histology codes on different branches in Chart 1 or Chart 2 are multiple primaries)?
Based on the information provided, this is a single primary. The 2011 tumor was not completely removed and progressed over the years. MP/H Rule M3 for malignant brain cancer applies. Do not change the original histology code. Use text fields to document the later histologic type of anaplastic astrocytoma, WHO grade III.