K65.4
Sclerosing mesenteritis
K65.4 (also written K654) is a billable ICD-10-CM diagnosis code for sclerosing mesenteritis. It is part of the FY2027 code set, effective October 1, 2026. It is one of the 7 codes in category K65 (Peritonitis). The Alphabetic Index lists it under 14 entries. Its coding notes include a Use additional code instruction, a Code also instruction, 17 Excludes1 entries and 8 Excludes2 entries.
Use additional code
Add the listed code as a secondary code, if known.
Code also
Two codes may be needed to describe the condition. This note gives no sequencing order.
Excludes1
Not coded here. The listed conditions generally should not be reported together.
- acute appendicitis with generalized peritonitis (K35.2-)
- aseptic peritonitis (T81.6)
- benign paroxysmal peritonitis (E85.0)
- chemical peritonitis (T81.6)
- gonococcal peritonitis (A54.85)
- neonatal peritonitis (P78.0-P78.1)
- pelvic peritonitis, female (N73.3-N73.5)
- periodic familial peritonitis (E85.0)
- peritonitis due to talc or other foreign substance (T81.6)
- peritonitis in chlamydia (A74.81)
- peritonitis in diphtheria (A36.89)
- peritonitis in syphilis (late) (A52.74)
- peritonitis in tuberculosis (A18.31)
- peritonitis with or following abortion or ectopic or molar pregnancy (O00-O07, O08.0)
- peritonitis with or following appendicitis (K35.-)
- puerperal peritonitis (O85)
- retroperitoneal infections (K68.-)
Excludes2
Not included here. Both codes may be reported if the patient has both conditions.
Also from chapter/block level (8 notes)
- certain conditions originating in the perinatal period (P04-P96)
- certain infectious and parasitic diseases (A00-B99)
- complications of pregnancy, childbirth and the puerperium (O00-O9A)
- congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
- endocrine, nutritional and metabolic diseases (E00-E88)
- injury, poisoning and certain other consequences of external causes (S00-T88)
- neoplasms (C00-D49)
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
Care settings
How CMS programs treat this code. These are CMS claim edits and list entries, not coverage or eligibility rules.
Home Health Primary
Accepted as the primary (principal) diagnosis on a home health claim. The Home Health Grouper assigns it to the MMTA - Gastrointestinal tract and Genitourinary system clinical group.
Source: CMS Home Health Grouper Software v07.2.26, effective October 1, 2026Hospital CC
Counts as a complication or comorbidity (CC) when reported as a secondary diagnosis on an inpatient claim. It does not count when the principal diagnosis is one of the 25 codes in its exclusion list. Some MS-DRGs also ignore a CC or MCC that defines the DRG.
Source: CMS MS-DRG Definitions Manual v44, effective October 1, 2026, Appendix CInclusion terms
Conditions classified to this code.
- Fat necrosis of peritoneum
- (Idiopathic) sclerosing mesenteric fibrosis
- Mesenteric lipodystrophy
- Mesenteric panniculitis
- Retractile mesenteritis
Alphabetic Index terms
Terms the official Alphabetic Index lists for this code. 14 entries
- Fat, necrosis, mesentery
- Fat, necrosis, omentum
- Fibrosis, fibrotic, sclerosing mesenteric (idiopathic)
- Lipodystrophy, mesenteric
- Mesenteritis, retractile
- Mesenteritis, sclerosing
- Necrosis, necrotic (ischemic), fat, fatty (generalized), abdominal wall
- Necrosis, necrotic (ischemic), fat, fatty (generalized), mesentery
- Necrosis, necrotic (ischemic), fat, fatty (generalized), omentum
- Necrosis, necrotic (ischemic), fat, fatty (generalized), peritoneum
- Necrosis, necrotic (ischemic), mesentery, fat
- Necrosis, necrotic (ischemic), omentum (with mesenteric infarction), fat