C41.9Malignant neoplasm of bone and articular cartilage, unspecified

C41.9 is the ICD-10-CM diagnosis code for malignant neoplasm of bone and articular cartilage, unspecified. It belongs to category C41 (malignant neoplasm of bone and articular cartilage of other and unspecified sites), block C40-C41 (malignant neoplasms of bone and articular cartilage) and chapter 2 (neoplasms). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within C41, choose C41.9 (bone and articular cartilage, unspecified) only when documentation doesn't support a more specific option: bones of skull and face (C41.0), mandible (C41.1), vertebral column (C41.2), ribs, sternum and clavicle (C41.3) and pelvic bones, sacrum and coccyx (C41.4).

As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" MS-DRG of its family, unless the principal diagnosis excludes it.

In MS-DRG v44.0, it is part of the grouping logic for DRG 542 (Pathological Fractures and Musculoskeletal and Connective Tissue Malignancy with MCC, relative weight 1.7211), DRG 543 (Pathological Fractures and Musculoskeletal and Connective Tissue Malignancy with CC, relative weight 1.006) and DRG 544 (Pathological Fractures and Musculoskeletal and Connective Tissue Malignancy without CC/MCC, relative weight 0.7406), in MDC 08 (Diseases and Disorders of the Musculoskeletal System and Connective Tissue), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 170.9 (malignant neoplasm of bone and articular cartilage, site unspecified).