Z85.850 Personal history of malignant neoplasm of thyroid

Billable ICD-10-CM code, FY2026. Exempt from present-on-admission (POA) reporting.

Applies from Z85 Personal history of malignant neoplasm

Excludes2 (not included here)

• personal history of benign neoplasm (Z86.01-)
• personal history of carcinoma-in-situ (Z86.00-)

Code first

• any follow-up examination after treatment of malignant neoplasm (Z08)

Use additional code

• code to identify:
• alcohol use and dependence (F10.-)
• exposure to environmental tobacco smoke (Z77.22)
• history of tobacco dependence (Z87.891)
• occupational exposure to environmental tobacco smoke (Z57.31)
• tobacco dependence (F17.-)
• tobacco use (Z72.0)

Applies from Z85.8 Personal history of malignant neoplasms of other organs and systems

Applicable to

• Conditions classifiable to C00-C14, C40-C49, C69-C75, C7A.098, C76-C79

Applies from Z85.85 Personal history of malignant neoplasm of endocrine glands

Applicable to

• Conditions classifiable to C73-C75

MS-DRG index

Defines the logic of DRG(s) 826-828 in MDC 17.

Approximate ICD-9-CM (GEMs)

• V10.87 Personal history of malignant neoplasm of thyroid

Medicare Code Edits (MCE v43.1 (April 2026))

• Unacceptable principal diagnosis: These codes describe a circumstance which influences care but is not a current illness or injury, or capture only an underlying condition, and are unacceptable as principal diagnosis.

Code annotations containing back-references to Z85.850

Back-references to Z85

• Use Additional: Z08 Encounter for follow-up examination after completed treatment for malignant neoplasm ("code to identify the personal history of malignant neoplasm (Z85.-)")
• Use Additional: Z15.0 Genetic susceptibility to malignant neoplasm ("code, if applicable, for any personal history of malignant neoplasm (Z85.-)")
• Type 2 Excludes: Z86.0 Personal history of in-situ and benign neoplasms and neoplasms of uncertain behavior ("personal history of malignant neoplasms (Z85.-)")

Diagnosis Index entries for Z85.850

• History › personal (of) › malignant neoplasm (of) › thyroid

Nearby codes

• Z85.84 Personal history of malignant neoplasm of eye and nervous tissue
• Z85.840 Personal history of malignant neoplasm of eye
• Z85.841 Personal history of malignant neoplasm of brain
• Z85.848 Personal history of malignant neoplasm of other parts of nervous tissue
• Z85.85 Personal history of malignant neoplasm of endocrine glands
• Z85.850 Personal history of malignant neoplasm of thyroid (this code)
• Z85.858 Personal history of malignant neoplasm of other endocrine glands
• Z85.89 Personal history of malignant neoplasm of other organs and systems
• Z85.9 Personal history of malignant neoplasm, unspecified