J91.0 ICD-10-CM Code: Malignant pleural effusion

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for J91.0 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2026Effective: October 1, 2025

Notes without a marker are published on J91.0 itself; “inherited from” names the category or block whose note applies here.

Coder workflow for J91.0

MedCoder structured workflow — derived from this code’s own official record

Choose the right path

1. Is the underlying (etiologic) condition the Code First note names documented?
   Yes → Sequence the underlying condition first, then J91.0.
   No → Continue; do not add an underlying condition the record does not document.

Consider J91.0. Then confirm the code is valid for the date of service in the Verify section.

Documentation check

The provider’s diagnostic statement

Codes are assigned from the provider’s documented diagnosis, not from clinical criteria, test values or a medication list (Guidelines I.A.19).

The underlying (etiologic) condition

Named in the Code First note; sequenced before this code when documented (Guidelines I.A.13).

Official instructions as workflow

• Excludes2 — not part of J91.0(2 notes)

  Coding workflow: The conditions named in this note are not included in J91.0. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

  CompareI50, M32.13

  See the official tabular notes · Guidelines I.A.12.b

• Code First — sequencing check(1 note)

  Coding workflow: Check whether the underlying or etiologic condition the note names is documented. When it is, sequence it before J91.0. Do not add an underlying condition the record does not document.

  See the official tabular notes · Guidelines I.A.13

Coding decision scenarios

Pattern scenarios for this code’s structure — decision rules, not clinical cases

Every row is derived from this code’s own record — its title, tabular notes, 7th-character family and same-category siblings — with fixed MedCoder wording; nothing is inferred about a patient. The official notes and guideline text are in the sections each row links to, and they control.

Indexed Clinical Terms (2)

Official source data — entries quoted as published, in the Index’s own lookup phrasing

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code. These are alphabetic-index entries shown as the Index writes them — lookup phrasing, not necessarily the wording of a final diagnosis.

• Effusion, malignant pleural
• Effusion, pleura, pleurisy, pleuritic, pleuropericardial, malignant

Don’t confuse J91.0 with…

MedCoder analysis — pairs from this code’s official notes, distinctions written by MedCoder

The codes most likely to be picked instead of J91.0 — named in its own official notes, or sharing its laterality or encounter family — with what separates them and which documentation moves the case. Each links to the full comparison.

• I50— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of pleural effusion in heart failure adds I50; it is not part of this code and both may be reported when both are documented.

  Full comparison: J91.0 vs I50 →

• M32.13— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of pleural effusion in systemic lupus erythematosus adds M32.13; it is not part of this code and both may be reported when both are documented.

  Full comparison: J91.0 vs M32.13 →

Relationships are read from this code's own official notes, its laterality siblings and its encounter family; the wording of each distinction is MedCoder editorial, and the documentation named in each “what moves you there” line is the official note phrase or sibling title itself. Source: CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a.

Verify Before Coding

• Principal-diagnosis restriction. This is a manifestation code: the Medicare Code Editor requires the underlying condition (etiology) to be sequenced first, with this code reported after it.
• CC as a secondary diagnosis (FY2026). Can raise the stay's MS-DRG severity tier.

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim in Claim Check.

Relationships & Classification

MedCoder structured relationships — computed from published CMS and AHRQ datasets

Other codes that name J91.0 or its code family, from the CMS ICD-10-CM tabular instructional notes. Tabular-note edges are stored at the code family level that carries each note.

Referenced by 1 Excludes1 note: J90 — Pleural effusion, not elsewhere classified.

These codes’ tabular lists mark this diagnosis as mutually exclusive — not reported together unless the conditions are documented as unrelated.

MS-DRG Grouper Relationships (FY2026)

Potential MS-DRG participation — not a DRG assignment.

FY2026 MS-DRG: CC — Complication or Comorbidity. Reported as a secondary diagnosis, this code raises the stay's MS-DRG severity tier — except when the principal diagnosis is one of 24 clinically related codes on its CMS exclusion list.

Named in the grouper logic of 3 MS-DRGs: DRG 180 (MDC 04), DRG 181 (MDC 04), DRG 182 (MDC 04).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Clinical classification (AHRQ CCSR):NEO074 — Conditions due to neoplasm or the treatment of neoplasm; RSP011 — Pleurisy, pleural effusion and pulmonary collapse.

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Related Codes

Same clinical process (MS-DRG)

Acts as CC — raises the severity of other admissions. CMS groups these diagnoses into one MS-DRG principal-diagnosis exclusion process — a CC/MCC on this list never raises severity when the principal diagnosis is also on it.

C78.30 — Secondary malignant neoplasm of unspecified respiratory organ, C78.39 — Secondary malignant neoplasm of other respiratory organs, C79.89 — Secondary malignant neoplasm of other specified sites, C79.9 — Secondary malignant neoplasm of unspecified site, C7A.00 — Malignant carcinoid tumor of unspecified site, C7A.098 — Malignant carcinoid tumors of other sites, C7A.1 — Malignant poorly differentiated neuroendocrine tumors, C7A.8 — Other malignant neuroendocrine tumors, C7B.00 — Secondary carcinoid tumors, unspecified site, C7B.09 — Secondary carcinoid tumors of other sites, C7B.1 — Secondary Merkel cell carcinoma, C7B.8 — Other secondary neuroendocrine tumors, C80.0 — Disseminated malignant neoplasm, unspecified, C80.1 — Malignant (primary) neoplasm, unspecified, D49.81 — Neoplasm of unspecified behavior of retina and choroid, D49.89 — Neoplasm of unspecified behavior of other specified sites, D49.9 — Neoplasm of unspecified behavior of unspecified site, J90 — Pleural effusion, not elsewhere classified, J94.0 — Chylous effusion, J94.2 — Hemothorax, +4 more

Principal diagnosis restriction (Medicare Code Editor)

Manifestation code — the underlying condition is sequenced first.

Same CMS-HCC risk category (V28)

CMS maps these diagnoses to the same Hierarchical Condition Category (Cancer Metastatic to Lung, Liver, Brain, and Other Organs; Acute Myeloid Leukemia Except Promyelocytic) for risk-adjusted payment.

C92.A1 — Acute myeloid leukemia with multilineage dysplasia, in remission, C92.A2 — Acute myeloid leukemia with multilineage dysplasia, in relapse, C93.00 — Acute monoblastic/monocytic leukemia, not having achieved remission, C93.01 — Acute monoblastic/monocytic leukemia, in remission, C93.02 — Acute monoblastic/monocytic leukemia, in relapse, C94.00 — Acute erythroid leukemia, not having achieved remission, C94.01 — Acute erythroid leukemia, in remission, C94.02 — Acute erythroid leukemia, in relapse, C94.20 — Acute megakaryoblastic leukemia not having achieved remission, C94.21 — Acute megakaryoblastic leukemia, in remission, C94.22 — Acute megakaryoblastic leukemia, in relapse, C94.40 — Acute panmyelosis with myelofibrosis not having achieved remission, C94.41 — Acute panmyelosis with myelofibrosis, in remission, C94.42 — Acute panmyelosis with myelofibrosis, in relapse, D46.22 — Refractory anemia with excess of blasts 2, E34.00 — Carcinoid syndrome, unspecified, E34.01 — Carcinoid heart syndrome, E34.09 — Other carcinoid syndrome, I31.31 — Malignant pericardial effusion in diseases classified elsewhere, R18.0 — Malignant ascites, +57 more

Related risk categories

These categories interact through CMS's HCC hierarchy — one can suppress the other's risk-adjustment weight when both are present on a claim.

Cancer Metastatic to Bone, Other and Unspecified Metastatic Cancer; Acute Leukemia Except Myeloid, Myelodysplastic Syndromes, Multiple Myeloma, and Other Cancers, Lung and Other Severe Cancers, Lymphoma and Other Cancers, Bladder, Colorectal, and Other Cancers, Prostate, Breast, and Other Cancers and Tumors

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical categories (Conditions due to neoplasm or the treatment of neoplasm, Pleurisy, pleural effusion and pulmonary collapse).

H47.42 — Disorders of optic chiasm in (due to) neoplasm, H47.521 — Disorders of visual pathways in (due to) neoplasm, right side, H47.522 — Disorders of visual pathways in (due to) neoplasm, left side, H47.529 — Disorders of visual pathways in (due to) neoplasm, unspecified side, H47.631 — Disorders of visual cortex in (due to) neoplasm, right side of brain, H47.632 — Disorders of visual cortex in (due to) neoplasm, left side of brain, H47.639 — Disorders of visual cortex in (due to) neoplasm, unspecified side of brain, J86.0 — Pyothorax with fistula, J86.9 — Pyothorax without fistula, J90 — Pleural effusion, not elsewhere classified, J91.8 — Pleural effusion in other conditions classified elsewhere, J92.0 — Pleural plaque with presence of asbestos, J92.9 — Pleural plaque without asbestos, J94.0 — Chylous effusion, J94.1 — Fibrothorax, J94.2 — Hemothorax, J94.8 — Other specified pleural conditions, J94.9 — Pleural condition, unspecified, J98.11 — Atelectasis, J98.19 — Other pulmonary collapse, +53 more

Same Index main term, other category

The ICD-10-CM Index to Diseases and Injuries files this code under the main term “Effusion”; these codes share that main term but sit in a different category of the Tabular List.

A15.6 — Tuberculous pleurisy (pleura, pleurisy, pleuritic, pleuropericardial, tuberculous NEC), A15.7 — Primary respiratory tuberculosis (pleura, pleurisy, pleuritic, pleuropericardial, tuberculous NEC, primary), G93.6 — Cerebral edema (brain), I31.31 — Malignant pericardial effusion in diseases classified elsewhere (pericardium, pericardial, malignant, in disease classified elsewhere), I31.39 — Other pericardial effusion (noninflammatory) (pericardium, pericardial), J90 — Pleural effusion, not elsewhere classified (pleura, pleurisy, pleuritic, pleuropericardial), J94.0 — Chylous effusion (chylous, chyliform), M25.40 — Effusion, unspecified joint (joint), M25.41 — Effusion, shoulder (joint, shoulder), M25.42 — Effusion, elbow (joint, elbow), M25.43 — Effusion, wrist (joint, wrist), M25.44 — Effusion, hand (joint, hand joint), M25.45 — Effusion, hip (joint, hip), M25.46 — Effusion, knee (joint, knee), M25.47 — Effusion, ankle and foot (joint, ankle), M25.48 — Effusion, other site (joint, specified joint NEC), M32.13 — Lung involvement in systemic lupus erythematosus (pleura, pleurisy, pleuritic, pleuropericardial, due to systemic lupus erythematosis), P28.89 — Other specified respiratory conditions of newborn (pleura, pleurisy, pleuritic, pleuropericardial, newborn), R18.8 — Other ascites (peritoneal)

Lab tests where this diagnosis supports Medicare coverage (NCD)

Medicare's National Coverage Determination (NCD) program lists this diagnosis as medical justification for these lab tests.

Prothrombin Time Test and INR (PT/INR)

Contextual Map

Every relationship of J91.0 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Run J91.0 with this related code in Claim Check

Hierarchy

• J00-J99 — Chapter 10: Diseases of the Respiratory System (J00-J99) (J00-J99)[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• J90-J94 — Other diseases of the pleura[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Referenced by Excludes1 notes

• J90 — Pleural effusion, not elsewhere classified[Excludes1]: “malignant pleural effusion (J91.0))”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Clinical classification (CCSR)

• NEO074 — Conditions due to neoplasm or the treatment of neoplasm[CCSR]— AHRQ CCSR for ICD-10-CM Diagnoses (HCUP)
• RSP011 — Pleurisy, pleural effusion and pulmonary collapse[CCSR]— AHRQ CCSR for ICD-10-CM Diagnoses (HCUP)

Risk adjustment (CMS-HCC)

• HCC 17 — Cancer Metastatic to Lung, Liver, Brain, and Other Organs; Acute Myeloid Leukemia Except Promyelocytic [CMS-HCC]: “Cancer Metastatic to Lung, Liver, Brain, and Other Organs; Acute Myeloid Leukemia Except Promyelocytic — supersedes HCC 18 (Cancer Metastatic to Bone, Other and Unspecified Metastatic Cancer; Acute Leukemia Except Myeloid), HCC 19 (Myelodysplastic Syndromes, Multiple Myeloma, and Other Cancers), HCC 20 (Lung and Other Severe Cancers), HCC 21 (Lymphoma and Other Cancers), HCC 22 (Bladder, Colorectal, and Other Cancers), HCC 23 (Prostate, Breast, and Other Cancers and Tumors)”— CMS-HCC V28 · 2026

MS-DRG Grouper

• CC — Complication or Comorbidity [MS-DRG severity]: “As a secondary diagnosis this code can raise the stay's MS-DRG severity tier (CC).”— CMS MS-DRG Definitions Manual (Appendix C) · FY2026
• DRG 180 — RESPIRATORY NEOPLASMS WITH MCC[MS-DRG]: “RESPIRATORY NEOPLASMS WITH MCC (MDC 04)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 181 — RESPIRATORY NEOPLASMS WITH CC[MS-DRG]: “RESPIRATORY NEOPLASMS WITH CC (MDC 04)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 182 — RESPIRATORY NEOPLASMS WITHOUT CC/MCC[MS-DRG]: “RESPIRATORY NEOPLASMS WITHOUT CC/MCC (MDC 04)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026

MDC crossing

• MDC 04 — Diseases and Disorders of the Respiratory System[MDC crossing]: “Diseases and Disorders of the Respiratory System — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs. 3,998 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2026

Index entries

• Effusion, malignant pleural[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
• Effusion, pleura, pleurisy, pleuritic, pleuropericardial, malignant[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026

Nearest codes

• J91 — Pleural effusion in conditions classified elsewhere[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• J91.8 — Pleural effusion in other conditions classified elsewhere[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Change history

• FY2016 — In the code set at ICD-10-CM adoption [Change history]— CMS release files (code change ledger) · icd10cm-fy2016

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data

CMS/CDC ICD-10-CM FY2026 tabular list, index and tables, effective October 1, 2025 Release, file and checksum · Publisher’s page

Claim edits Official source data

CMS Definitions of Medicare Code Edits — v43.1 (April 2026) Release, file and checksum · Publisher’s page

Inpatient payment groups Official source data

CMS MS-DRG Definitions Manual (incl. Appendix B diagnosis index, Appendix C CC/MCC list, Appendix E procedure index) and IPPS Final Rule tables — v43 Release, file and checksum · Publisher’s page

Risk adjustment Official source data

2026 Mid-Year Final ICD-10 Mappings + Model Software (cms.gov/files/zip/2026-midyear-final-icd-10-mappings.zip, 2026-midyear-final-model-software.zip) — CMS-HCC V28, PY2026 mid-year final release Release, file and checksum · Publisher’s page

Change history and date-of-service validity Official source data

CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page

Comparisons, relationships and the contextual map MedCoder structured relationship

Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears

Summary and FAQ answers MedCoder explanation

Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Labels on this page: Official source data · MedCoder structured relationship · MedCoder explanation. How to read the labels · All data sources and release dates

Nearest Codes in This Family

Official ICD-10-CM classifications closest to J91.0 in its code family, with their registry titles.

• J91 — Pleural effusion in conditions classified elsewhere
• J91.8 — Pleural effusion in other conditions classified elsewhere

View all codes in the J91 family