ICD-10 code R91.1 is a crucial diagnosis code in the medical field, specifically used to classify Solitary Pulmonary Nodules (SPN), also known as a coin lesion of the lung. This code is part of the International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM), and is essential for medical billing, data analysis, and clinical documentation.
What is ICD-10 Code R91.1?
Diagnosis code R91.1 is designated as a billable and specific code, meaning it is precise enough to be used for reimbursement purposes. The code officially came into effect on October 1, 2015, and the current version is valid for the fiscal year 2025, starting October 1, 2024. This code is unique to the American ICD-10-CM version; international versions may differ.
Applicable Terms for R91.1
ICD-10 code R91.1 is applicable in cases described as:
- Coin lesion lung
- Solitary pulmonary nodule, subsegmental branch of the bronchial tree
These terms indicate a single, isolated lesion found within the lung tissue, often identified during chest imaging.
Clinical Significance of Diagnosis Code R91.1
The use of diagnosis code R91.1 points to the presence of a pulmonary nodule. Clinically, a solitary pulmonary nodule is defined as a single, well-defined lesion, generally smaller than 3 cm in diameter, surrounded by lung parenchyma. These nodules are frequently discovered incidentally on chest radiographs or CT scans performed for other reasons.
Understanding Solitary Pulmonary Nodules
A solitary pulmonary nodule, coded under R91.1, appears as a round or oval shadow on chest X-rays, resembling a coin. These nodules can represent a variety of conditions, ranging from benign to malignant. Potential causes include:
- Benign conditions: Granulomas (from prior infections like tuberculosis or fungal infections), hamartomas, intrapulmonary lymph nodes, and scars.
- Malignant conditions: Primary lung cancer, metastatic cancer.
Due to the possibility of malignancy, identifying and characterizing a solitary pulmonary nodule is critical. Further diagnostic steps are often necessary to determine the nature of the nodule, which may include:
- Review of past medical imaging: To assess nodule growth rate.
- High-resolution CT scan: To better characterize the nodule’s features (size, shape, density, calcification patterns).
- PET scan: To evaluate metabolic activity and the likelihood of malignancy.
- Biopsy: Through bronchoscopy, needle biopsy, or surgical resection, to obtain tissue for pathological examination.
ICD-10-CM R91.1 Code History
The ICD-10-CM code R91.1 for Solitary Pulmonary Nodule has been consistently used since its introduction in 2016. There have been no revisions or changes to this code from 2016 through the current 2025 update, indicating its stable and ongoing relevance in medical coding.
| Year | Effective Date | Change |
|---|---|---|
| 2016 | 10/1/2015 | New code |
| 2017-2025 | 10/1/2016 – 10/1/2024 | No change |
Related ICD-10 Codes
Understanding related ICD-10 codes can provide broader context. Codes adjacent to R91.1 include other abnormal findings on diagnostic imaging of the lung and related systems:
- R91: Abnormal findings on diagnostic imaging of lung (parent category)
- R91.8: Other nonspecific abnormal finding of lung field
- R90: Abnormal findings on diagnostic imaging of central nervous system
- R92: Abnormal and inconclusive findings on diagnostic imaging of breast
Conclusion
ICD-10 code R91.1, Solitary Pulmonary Nodule, is a vital tool for accurately documenting and classifying lung lesions. Its precise application is essential for proper medical coding, billing, and ensuring appropriate patient care and follow-up in cases involving pulmonary nodules. The consistent use and definition of R91.1 in the ICD-10-CM system highlight its importance in respiratory medicine and diagnostic imaging.
