#1: MP/H Rules
#3: Brain and CNS
Source 1: 2007 MP/H Rules
Notes: Benign Brain and CNS Tumors
Source 2: ICD-O-3
MP/H Rules/Histology--Brain and CNS: What is the histology code for a patient with a pathology report Final Diagnosis indicating, mucin-rich neuroepithelial neoplasm, favor low-grade? See Discussion.
The pathologist noted this was a challenging brain neoplasm that did not easily fit into a specific WHO diagnostic classification. Multiple differential diagnoses were given including pilomyxoid astrocytoma, ganglioglioma and dysembryoplastic neuroepithelial tumor (DNET), but there were no definitive features characteristic of any of these tumors. In the Comment section following the Final Diagnosis, it further states: "In summary, the tumor appears to be a difficult to classify non-infiltrating glial/glioneuronal neoplasm without definitive high-grade features."
Code as 9505/1, Ganglioglioma, NOS. The Multiple Primaries/Histology Rules for Benign and Borderline Intracranial and CNS Tumors Chart 1 lists several histology codes for neuronal and mixed neuronal-glial tumors. Ganglioglioma, formerly Glioneuroma that is now obstolete in ICD-O-3, is the most applicable in this situation.