Convert to ICD-10-CM: 
172.4 converts approximately to:
- 2015/16 ICD-10-CM C43.4 Malignant melanoma of scalp and neckOr: 
- 2015/16 ICD-10-CM D03.4 Melanoma in situ of scalp and neck
 ICD-9-CM Volume 2 Index entries containing back-references to 
172.4:
- Melanoma (malignant) (M8720/3) 172.9  neck 172.4 neck 172.4
  scalp 172.4 scalp 172.4