Melanoma in situ of left upper limb, including shoulder

This code signifies the presence of melanoma that is confined to the epidermis (in situ) on the patient's left upper limb, which includes the shoulder region. This is a non-invasive form of skin cancer where the abnormal melanocytes have not penetrated the basement membrane.

Apply this code when documentation explicitly states a diagnosis of melanoma in situ located on the left arm or shoulder. This diagnosis is typically confirmed by a pathology report following a biopsy or excision.

• Ensure the pathology report confirms "in situ" and specifies the left upper limb or shoulder.
• Do not use this code for invasive melanoma; refer to the C43 series for invasive lesions.
• Laterality is crucial; verify "left" upper limb.