#1: MP/H Rules
#3: Brain and CNS
Source 1: WHO Class CNS Tumors
Notes: 4th edition, 2016
Source 2: 2007 MP/H Rules
Notes: Benign Brain
MP/H Rules/Histology--Brain and CNS: Is meningioma with atypical features coded as meningioma (9530/0) or atypical meningioma (9539/1)? See Discussion.
Pathology report microscopic description: The tumor is a meningothelial neoplasm (EMA+; BCL-2 and CD34 negative) with prominent collagen deposition. Necrosis and prominent nucleoli are present; no other atypical features are seen. Mitoses are present, up to 2 per 10 high-powered fields. Final Diagnosis: Dura, bicoronal craniotomy (specimen A): Meningioma with atypical features.
There is no rule in benign brain and CNS section of Multiple Primary/Histology (MP/H) Rules stating to code the most specific histologic term when the diagnosis is (something less specific, i.e., adenocarcinoma). This rule is in other site chapters of MP/H but appears missing in the benign brain and CNS section.
Code as meningioma, NOS (9530/0). This lesion has some of the features of an atypical meningioma (necrosis and prominent nucleoli), but it does not fit the definition of atypical meningioma in WHO Classification of Tumors of the Central Nervous System. Use text fields to document the details.