Biopsy is the essential procedure for diagnosis of melanoma. While it requires minor surgery and removal of tissue, it should not provoke undue anxiety. Biopsy involves minimal discomfort, and no non-invasive procedure can provide the same essential diagnostic information.

The definition of biopsy is:

Removal and microscopic examination of tissue for the purpose of establishing a precise diagnosis.

In the diagnosis of melanoma or suspected melanoma, tissue is biopsied when a lesion is

1. Suspected to be a cutaneous or metastatic melanoma, or 
2. Known to be a melanoma and tissue is needed for staging the tumor cells in order to plan additional diagnostic procedures and treatment. A dermatologist or dermatologic surgeon can biopsy a cutaneous melanoma. A primary care physician may perform a biopsy or refer a patient to a dermatologist or surgeon when a biopsy is indicated.

Microscopic tissue examination for melanoma is done by a dermatopathologist, dermatologist, or pathologist using appropriate microscopic technique. The dermatopathologist, dermatologist or pathologist reports tissue-examination findings to the patient’s physician. If there is a finding of melanoma and/or other pathologic skin condition, the biopsy becomes the first step in planning additional diagnostic procedures and adequate therapy. A dermatopathologist is a specialist trained in both dermatology and pathology—special training and experience in the microscopic examination and diagnosis of skin lesions.

The selection of biopsy technique is guided, in large part, by the size and location of the lesion to be biopsied. The physician performing the procedure should explain to the patient;

1. The reason for the biopsy.
2. The type of biopsy to be performed.
3. How the procedure will be performed. Removal of tissue is always performed using local anesthetic unless there are medical reasons for general anesthesia, and is usually performed in a physician’s office or outpatient setting.

Excisional biopsy is a common technique for removing a suspect skin lesion for microscopic examination. Excisional biopsy may remove the entire lesion along with a margin of tissue that is not visibly a part of the lesion. If the lesion proves to be a thin melanoma the excisional biopsy may have removed all the tissue necessary to effectively treat the melanoma. If the melanoma proves to be moderately or substantially thick, the biopsy provides information for determining;

1. Whether additional tissue removal at the biopsy site is indicated, and 
2. Whether additional diagnostic procedures are indicated to determine if the tumor has spread (metastasized) to lymph nodes or distant sites. (Click on thickness  for an explanation of the relationship between survival and tumor thickness).

The wound created by a small excisional biopsy may or may not require stitches.

Excisional biopsy is usually the diagnostic procedure of choice for cutaneous melanoma unless considerations such as the size of the lesion make it less acceptable. Incisional biopsy may be the procedure of choice for very large lesions.

Incisional biopsy may be considered when a lesion is very large because the total removal of the lesion by excisional biopsy would create an unacceptably large surgical wound. In incisional biopsy; 

1. A slice of tissue is removed from the lesion by surgical excision, or 
2. A sample of tissue is removed by "punch" biopsy using a hollow, circular scalpel-like instrument.

Nail bed biopsy requires partial or total removal of the fingernail or toenail for best results. Nail removal and biopsy of nail-bed tissue are performed under local anesthesia. Biopsy of the suspect lesion may be excisional or incisional, depending on the size of the lesion. A suspect lesion in the nail bed often grossly appears as a "nail streak". Click here for an explanatin of Acral lentiginous melanoma. The type of melanoma that occurs most frequently in the nail bed.

Needle biopsy is rarely used to remove tissue from a primary cutaneous melanoma. It may be performed to remove tissue from internal organs, lymph nodes or subcutaneous tissue for diagnosis of metastatic melanoma. Tissue is removed by negative suction through a fine, hollow needle. Needle biopsy is performed by a specialist physician or surgeon.

As soon as tissue is surgically removed, it is prepared for microscopic examination by a pathologist—a specialist in microscopic diagnosis. The two common techniques of tissue preparation are: 

1. Flash-freezing the tissue, slicing it into thin sections, and staining it for special dyes for examination under a microscope.
2. Fixing the tissue in special chemicals, placing it in a paraffin block and slicing it into thin sections, and staining it with special dyes for microscopic examination.

The pathologist examines the tissue;

1. As directed by the patient’s physician—e.g., assessing tissue for any indications of malignancy, and
2. With a pathologist’s professional eye to detect any other abnormalities that should be brought to the attention of the patient’s physician. The pathologist sends a report of findings to the patient’s physician. The physician and patient should discuss the findings. The patient may wish to ask for a copy of the pathology report to maintain in his/her files.

Melanoma that has metastasized, or is believed to have potential for metastasis, may require additional biopsies of lymph nodes and internal organs in consultation with an oncologist (physician specializing in cancer therapy).

Mohs Micrographic Surgery is a technique for taking serial excisions from a known or suspected tumor and examining each slice in frozen section under a microscope until no more tumor tissue is identified. The serial excisions are repeated until all parts of the tumor have been removed. Mohs surgery is used to treat contiguous tumor, not satellite tumors.

The Mohs procedure is performed by a surgeon with training and experience in the technique. A micrographic procedure is usually done in an outpatient setting under local anesrhesia, and may require several hours.

The most effective use of Mohs micrographic surgery is in treatment of tumors that spread by contiguous growth. The most frequent application of the technique in treating skin cancer is for basal cell carcinoma and squamous cell carcinoma.

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