Diagnostic basis of melanoma

The diagnosis of melanoma is generally not difficult, and a few atypical cases need to be confirmed by pathological examination. Indirect immunofluorescence labeling of melanin tissue, double PAP immunoenzyme labeling assay and pigmentogen examination are helpful for diagnosis, and are helpful for the diagnosis of "non-pigmented" or oligo-pigmented melanoma and for distinguishing benign nevus cell tumors and whether they have become malignant.

1. Diagnostic basis for malignant melanoma of the skin

1. Medical history and symptoms

A detailed medical history and physical examination are very important for diagnosis. If any pigmented skin lesion on the body surface suddenly grows faster, has a pigment halo or loss of pigment around it, has scaling, exudation, ulceration, bleeding, hair loss on the surface, satellite nodules nearby, or local itching and pain, melanoma should be considered. Recommended reading: Treatment of nasal and sinus melanoma Diagnosis of nasal melanoma

2. Laboratory examination

(1) Urine examination: Usually laboratory tests are not very helpful for diagnosis. However, when melanoma has metastasized widely, a large amount of melanogen and its metabolites may appear in the urine, resulting in dark urine.

(2) Histopathological examination: A diagnostic description should be made of the nature of the melanoma, tumor type, invasion depth, maximum vertical thickness, cell division phase, presence of surface ulcers, invasion of basal blood vessels and lymphatic vessels, and presence of cellular inflammatory response.

2. Examination items for malignant melanoma of the skin

1. Histopathological examination

Abnormal proliferation of melanocytes can be seen, with nests of cells in the epidermis or at the epidermal-dermal junction. The nucleoli are usually eosinophilic and "bird's eye-like". In invasive melanomas, melanoma cells can be seen in the dermis or subcutaneous tissue. Recommended reading: Diagnosis of anal canal malignant melanoma Complications of malignant melanoma.

For typical melanoma, HE-stained sections and pathological examinations are usually sufficient for a clear diagnosis. However, for atypical melanoma, such as amelanotic melanoma, some special techniques (such as S100 and HMB45 immunohistochemical examinations) are often required to facilitate diagnosis.

2. Urine test

When a large amount of melanogen and its metabolites appear in the urine, resulting in dark urine, it is helpful for the diagnosis of melanoma.

Examinations such as X-ray, ultrasound, CT, MRI and radionuclide scanning can help determine whether the melanoma has metastasized to the lungs, liver, kidneys, brain and other internal organs.