`Z42.1` Encounter for breast reconstruction following mastectomy

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

Excludes1 (never code together)

deformity and disproportion of reconstructed breast (N65.1-)

Applies from Z42 Encounter for plastic and reconstructive surgery following medical procedure or healed injury

Excludes1 (never code together)

encounter for cosmetic plastic surgery (Z41.1)
encounter for plastic surgery for treatment of current injury - code to relevent injury

MS-DRG index

Defines the logic of DRG(s) 606-607 in MDC 09.

Approximate ICD-9-CM (GEMs)

V51.0 Encounter for breast reconstruction following mastectomy

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

Adult diagnoses (age 15 through 124): Age conflict edit. These diagnoses are clinically expected only in patients age 15 through 124.

Code annotations containing back-references to Z42.1

Back-references to Z42.1

Type 1 Excludes: Z41.1 Encounter for cosmetic surgery ("encounter for post-mastectomy breast implantation (Z42.1)")
Type 1 Excludes: Z44.3 Encounter for fitting and adjustment of external breast prosthesis ("encounter for breast reconstruction following mastectomy (Z42.1)")
Type 1 Excludes: Z45.81 Encounter for adjustment or removal of breast implant ("encounter for breast reconstruction following mastectomy (Z42.1)")

Back-references to Z42

Type 1 Excludes: Z41.1 Encounter for cosmetic surgery ("encounter for plastic and reconstructive surgery following medical procedure or healed injury (Z42.-)")

Diagnosis Index entries for Z42.1

Admission (for) › breast reconstruction following mastectomy
Encounter (with health service) (for) › breast reconstruction following mastectomy

Nearby codes

Z42 Encounter for plastic and reconstructive surgery following medical procedure or healed injury
Z42.1 Encounter for breast reconstruction following mastectomy (this code)
Z42.8 Encounter for other plastic and reconstructive surgery following medical procedure or healed injury