2006 ICD-9-CM Volume 1 Diagnosis Codes Home > Neoplasms 140-239 > Malignant Neoplasm Of Respiratory And Intrathoracic Organs 160-165 > Malignant Neoplasm Of Thymus Heart And Mediastinum 164.* > 2006 ICD-9-CM Diagnosis 164.8 Malignant neoplasm of other parts of mediastinum View the most recent version of ICD-9-CM 164.8 164.8 is a specific code that can be used to specify a diagnosis View the ICD-9-CM Volume 1 164.* hierarchy Alternate Terminology Malignant neoplasm of contiguous or overlapping sites of thymus, heart, and mediastinum whose point of origin cannot be determined