Excludes1 pair

D15.0 vs E32.8

D15.0 and E32.8 are not coded together. ICD-10-CM declares them mutually exclusive with an Excludes1 note — the two conditions are not expected to occur together, so exactly one of them is normally correct for a given encounter. The Official Guidelines carve out one exception: if the two conditions are clearly unrelated to each other, both may be reported.

The official note, declared on E32.8
thymoma (D15.0)
D15.0

Benign neoplasm of thymus

Billable
Chapter 2
Neoplasms
Section
D10-D36
Indexed under
  • Thymoma › microscopic
E32.8

Other diseases of thymus

Billable
Chapter 4
Endocrine, nutritional and metabolic diseases
Section
E20-E35
Indexed under
  • Kopp's asthma
  • Lymphatism
  • Thymitis
  • Asthma, asthmatic › Kopp's
  • Asthma, asthmatic › thymic

These two codes sit in different chapters of the Tabular List, which is usually the clearest signal that they describe different underlying processes rather than different degrees of the same one.

Excludes1 is not always absolute: where two conditions covered by the note are genuinely unrelated, CMS guidance permits reporting both. Document the reasoning rather than assuming it. More on Excludes1 vs Excludes2 · FY2027