{"code":"C21.0","type":"code","title":"Malignant neoplasm of anus, unspecified","codeAlso":[],"includes":[],"modern_v":"official26","codeFirst":[],"excludes1":["Kaposi's sarcoma of gastrointestinal sites (C46.4)"],"excludes2":["malignant carcinoid tumors of the colon (C7A.02-)","malignant melanoma of anal margin (C43.51)","malignant melanoma of anal skin (C43.51)","malignant melanoma of perianal skin (C43.51)","other and unspecified malignant neoplasm of anal margin (C44.500, C44.510, C44.520, C44.590)","other and unspecified malignant neoplasm of anal skin (C44.500, C44.510, C44.520, C44.590)","other and unspecified malignant neoplasm of perianal skin (C44.500, C44.510, C44.520, C44.590)","gastrointestinal stromal tumors (C49.A-)"],"isBillable":true,"fyEffectivity":{"fy2026":true,"fy2027":true,"billableFy2026":true,"billableFy2027":true},"sibling_codes":["C21","C21.1","C21.2","C21.8"],"inclusionTerms":[],"sibling_titles":{"code":"C21.8","title":"Malignant neoplasm of overlapping sites of rectum, anus and anal canal","isBillable":true},"useAdditionalCode":[],"clinicalDefinition":"Malignant neoplasm of anus, unspecified is a billable ICD-10-CM diagnosis code (C21.0). Excludes1 (not coded here): Kaposi's sarcoma of gastrointestinal sites (C46.4). Excludes2 (not included here): malignant carcinoid tumors of the colon (C7A.02-); malignant melanoma of anal margin (C43.51); malignant melanoma of anal skin (C43.51); malignant melanoma of perianal skin (C43.51); other and unspecified malignant neoplasm of anal margin (C44.500, C44.510, C44.520, C44.","officialDefinition":"Malignant neoplasm of anus, unspecified is a billable ICD-10-CM diagnosis code (C21.0). Excludes1 (not coded here): Kaposi's sarcoma of gastrointestinal sites (C46.4). Excludes2 (not included here): malignant carcinoid tumors of the colon (C7A.02-); malignant melanoma of anal margin (C43.51); malignant melanoma of anal skin (C43.51); malignant melanoma of perianal skin (C43.51); other and unspecified malignant neoplasm of anal margin (C44.500, C44.510, C44.520, C44.590); other and unspecified malignant neoplasm of anal skin (C44.500, C44.510, C44.520, C44.590); other and unspecified malignant neoplasm of perianal skin (C44.500, C44.510, C44.520, C44.590); gastrointestinal stromal tumors (C49.A-).","seventhCharacterInstructions":[],"workflowProtocols":[],"guidelines":{"whenToUse":[],"whenNotToUse":[],"commonBillingMistakes":[],"codeComparisons":[],"documentationChecklist":[]},"domainLandscape":{"summary":"Primary diagnostic domain and clinical landscape evaluation.","keyCategories":[],"diagnosticContinuum":"Progression continuum from acute presentation to resolution."},"children":[],"hierarchy":[],"relatedCodes":[],"relevantCPTCodes":[],"documentationTips":[],"caseStudies":[],"description":"","overview":""}