2026 ICD-10-CM Diagnosis Code Z85.238Personal history of other malignant neoplasm of thymus
Z85.238 is a billable ICD-10-CM diagnosis code for personal history of other malignant neoplasm of thymus. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 826 through 830, 843 through 845. The code is not accepted as a principal diagnosis by the Medicare Code Editor and exempt from POA reporting. Coders also document this condition as history of malignant neoplasm of endocrine gland. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Personal history of malignant neoplasm.
Code Identity
Code Classification
Code EditsBilling
Medicare Code Editor checks that affect claim validity for Z85.238.
Present on Admission (POA)Billing
Z85.238 is exempt from POA reporting on inpatient claims to general acute care hospitals. Review other POA exempt codes.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- History of malignant neoplasm of endocrine gland
- History of malignant neoplasm of mediastinum
- History of malignant neoplasm of thymus
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Inclusion Terms
- Conditions classifiable to C37
These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
- History
- personal (of) - See Also: History, family (of);
- malignant neoplasm (of) - Z85.9
- thymus NEC - Z85.238
External Cause of Injuries IndexGuidance
References for this code in the External Cause of Injuries Index.
- History
- personal (of)
- malignant neoplasm (of)
- thymus NEC
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Thymus Cancer
The thymus is a small organ in your upper chest, under your breastbone. Before birth and during childhood, the thymus helps the body make a type of white blood cell. These cells help protect you from infections.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert Z85.238 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About Z85.238Overview
Is Z85.238 (Personal history of malignant neoplasm of thymus) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report personal history of other malignant neoplasm of thymus on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does Z85.238 group to?
On inpatient claims, personal history of other malignant neoplasm of thymus maps to MS-DRG 826, 827, 828, 829, 830, 843, 844, 845, with relative weights from 0.8516 to 4.6778 depending on complications. Higher weights mean higher Medicare reimbursement.
Can Z85.238 be a principal diagnosis?
No. The Medicare Code Editor rejects this code as a principal diagnosis because personal history of other malignant neoplasm of thymus describes a circumstance that influences health status rather than a current illness. Report it as a secondary diagnosis.
Is Z85.238 exempt from POA reporting?
Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for personal history of other malignant neoplasm of thymus on inpatient claims.
What is the ICD-9 equivalent of Z85.238?
Under the General Equivalence Mappings, personal history of other malignant neoplasm of thymus converts to ICD-9-CM V10.29 (hx-intrathoracic mal NEC). The mapping is approximate, so confirm the match fits the documentation.
