C40.31Malignant neoplasm of short bones of right lower limb

C40.31 is the ICD-10-CM diagnosis code for malignant neoplasm of short bones of right lower limb. It belongs to category C40 (malignant neoplasm of bone and articular cartilage of limbs), 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 C40.3 (malignant neoplasm of short bones of lower limb), C40.31 is specifically for malignant neoplasm of short bones of right lower limb. Related codes cover unspecified lower limb (C40.30) and left lower limb (C40.32).

Use an additional code to identify major osseous defect, if applicable (M89.7-).

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 170.8 (malignant neoplasm of short bones of lower limb).