ICD-10 Code D21.12 – Benign neoplasm of connective and other soft tissue of left upper limb, including shoulder (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D21.12 – Benign neoplasm of connective and other soft tissue of left upper limb, including shoulder
What it is
This code identifies a noncancerous growth arising from connective or other soft tissue in the left upper limb, including the shoulder. It is used when the lesion is documented as benign and located on the left side.
Clinical signs
Findings may include a localized, slow-growing soft tissue mass, swelling, or a palpable lump. Clinical features vary; refer to documentation for the exact tissue type, size, and whether imaging or biopsy supported the diagnosis.
When to use this code
Use D21.12 when the provider documents a benign neoplasm in the left arm, forearm, wrist, hand, or shoulder soft tissues. Apply it for confirmed benign tumors, not for nonspecific pain or swelling without a documented neoplasm. If the record only says “mass” or “lesion,” check documentation before coding.
Do not use for
Do not use this code for malignant tumors, metastatic disease, or unspecified soft tissue masses. If the lesion is in a different limb or the site is not clearly documented, choose the correct code or check documentation.
Coding tip
Verify that the note states both benign behavior and left upper limb or shoulder location before assigning D21.12.