Diagnosis of advanced melanoma

Melanoma, also known as malignant melanoma, is a type of malignant tumor derived from melanocytes. It is common in the skin, mucous membranes, choroids and other parts of the eye. Melanoma is the most malignant tumor among skin tumors and is prone to distant metastasis. Early diagnosis and treatment are therefore particularly important.

(1) Physical examination

The diagnosis of melanoma mainly relies on visual examination. Pigmented moles with irregular colors or shapes, and previous pigmented moles that have recently enlarged or changed in shape should all be noted. It is recommended to use the above-mentioned "ABCDE" standard to conduct regular self-examination of existing pigmented moles, or go to the hospital for consultation.

(2) Biopsy

If the skin lesion is suspected to be melanoma after medical treatment, a complete excision biopsy of the lesion should be performed, and the lesion should be sent for pathological examination after surgery to obtain accurate T staging. The cutting margin should be 0.3 to 0.5 cm, and the incision should be along the direction of the skin grain (such as the limbs, the incision should generally be along the long axis). Avoid direct extended excision to avoid changing the regional lymphatic return and affecting the quality of the sentinel lymph node biopsy in the future. For lesions in the face, palms, soles, ears, fingers, toes, or under the nails, or huge lesions, when complete excision is not possible, full-thickness skin lesion excision or puncture biopsy can be considered. If the tumor is huge and ruptured, or metastasis has been clearly confirmed, a puncture or excisional biopsy of the lesion can be performed.

(3) Imaging examination

Imaging examinations should be determined based on local actual conditions and the patient's economic situation. Mandatory examination items include regional lymph node (neck, axilla, groin, fossa, etc.) ultrasound, chest X-ray or CT, abdominal and pelvic ultrasound, CT or MRI, whole-body bone scan and head examination (CT or MRI). Patients with good economic conditions can undergo whole-body PET-CT examinations, especially those with unknown primary lesions. PET is a method that is more likely to detect subclinical metastases. Most examiners believe that for early localized melanoma, PET is not sensitive to detecting metastatic lesions and has a low benefit rate. For stage III patients, PET/CT scans are more useful and can help identify lesions that cannot be clearly diagnosed by CT, as well as areas that cannot be displayed by conventional CT scans (such as limbs).

(4) Laboratory examination

Including blood routine, liver and kidney function and LDH, these indicators are mainly for preparation for subsequent treatment and to understand the prognosis. Although LDH is not a sensitive indicator for detecting metastasis, it can guide prognosis. There is no specific serum tumor marker for melanoma, and tumor marker testing is not recommended.