How is Melanoma Diagnosed?

To achieve an accurate diagnosis for melanoma it is important to consider the clinical appearance, the histopathological criteria, and additional parameters.  The clinical appearance includes changes in size, shape, elevation, color and texture of the melanoma. Histopathological criteria refer to a set of factors that are examined on a microscopic level in the lab once the spot is removed and sent to pathology.  Additional parameters include the patient’s age, gender, anatomic location of the melanoma, and additional blood and radiology tests.

In the medical literature, melanoma diagnosis is often divided into clinical diagnosis and pathological diagnosis.  Clinical diagnosis includes first recognizing the clinical appearance is abnormal (by either a patient or doctor), recommending appropriate removal of tumor, and possible radiological testing (chest x-rays, CT scan, PET scan) and bloodwork (CBC, LDH,).  Pathological diagnosis comes after the removed lesion is examined in the lab under a microscope.  This exam includes histological criteria results that will enable the treating physician to both stage and decide on future treatments for the patient.  Usually, the clinical and pathological diagnoses are similar, but in cases of thin melanomas that are invasive or ulcerated, the pathological diagnosis will be more reflective of the true situation. 

An incisional biopsy technique is appropriate when the suspicion for melanoma is low, the lesion is large, or when it is impractical to perform an excision. Otherwise, excision is the removal of choice. Spots that are questionable or thin non-ulcerated melanomas are often first removed in a doctor’s office and the specimen sent for biopsy. If the biopsy comes back positive for melanoma, the patient will have to return for further excision of the area since most doctor’s offices do not remove a 1-2 cm margin of normal skin.  It is important to stress if this type of removal is performed and there is any suspicion the lesion may be melanoma, a full thickness incisional removal is performed either by punch biopsy or scalpel.  Without an intact tumor, thickness is not measurable, staging is inaccurate and treatment then becomes a guessing game.  If the lesion (spot) is readily identifiable as melanoma or has a high probability, it is best to have a surgeon remove both the lesion and the appropriate skin margins after first deciding if a sentinel lymph node biopsy(SLNB) is warranted.  Sentinel lymph node biopsy is recommended for Stage 1b-Stage IV melanomas.

For further information on biopsies and pathology reports:  http://www.thecancer.info/therapy/biopsyreport.htm