Billable / Specific Code
ICD-10-CM C21.8 is the diagnosis code for Malignant neoplasm of overlapping sites of rectum, anus and anal canal. This code falls under the section "Malignant neoplasms of digestive organs" within Chapter 2 — Neoplasms (C00-D49). It is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes. Medical coders and healthcare providers use this code to document and classify diagnoses in electronic health records, insurance claims, and clinical databases.
Understanding where C21.8 sits in the ICD-10-CM classification helps ensure proper coding:
Yes, C21.8 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes.
C21.8 is the ICD-10-CM diagnosis code for "Malignant neoplasm of overlapping sites of rectum, anus and anal canal". It is used by healthcare providers to classify and document this condition in medical records and insurance claims.
The parent code of C21.8 is C21 ("Malignant neoplasm of anus and anal canal"). C21.8 provides a more specific classification within this category.
C21.8 is located in Section C15-C26 — "Malignant neoplasms of digestive organs" within Chapter 2 of the ICD-10-CM Tabular List.
Use C21.8 when the patients documented diagnosis matches "Malignant neoplasm of overlapping sites of rectum, anus and anal canal" and the clinical documentation supports this level of specificity. Always verify with the latest ICD-10-CM guidelines and payer requirements.
The ICD-10-CM code for Malignant neoplasm of overlapping sites of rectum, anus and anal canal is C21.8.
Yes, C21.8 can be used as a primary diagnosis code since it is billable and specific.
C21.8 is in Chapter 2 of the ICD-10-CM Tabular List.
Yes, C21.8 is a valid ICD-10-CM code for the 2026 fiscal year, subject to official CMS updates.