A review of data from a physician owned professional liability insurer in the US that insures over 1,000 pathologists throughout the country reveals a recurrent problem in the misdiagnosis and failure to diagnose melanoma. A study done by the liability insurer of all pathology claims reported between 1990 to 2001 demonstrated that 8.6% of these claims were related to either skin cancer or melanoma. Approximately 14% of claims in dermatology were denoted by these same key words. Subsequent analysis of 218 cases of surgical pathology specimens and fine needle aspiration biopsy claims from 1995 to 1997 revealed that 11% of the cases were misdiagnosis of melanoma and that 70% of cases were false negative diagnoses.
Understanding Melanoma
Melanoma is a potentially deadly skin cancer. The most serious and aggressive form of skin cancer, melanoma develops from cells that produce the pigment melanin from which skin color is derived. The abnormal melanocytes may occur in the eyes and sometimes in internal organs, in addition to forming in the skin.
Melanoma is often caused, in part, from ultraviolet radiation exposure. This exposure may occur in sunlight or with a tanning lamp/tanning bed. A preventative measure is limiting exposure to ultraviolet radiation. Melanocytes may have damaged DNA that results in unchecked growth of the melanocytes into a mass of malignant cells. This DNA damage is probably due most often to UV light exposure. Other potential risk factors include sunburn, higher UV light exposure from living in latitudes closer to the equator or at greater elevation, a family history of melanoma, a weakened immune system. Fair skin that results in less protection from melanoma, because melanocytes are normally protective. People with fair skin have fewer melanocytes.
Because melanoma is a very aggressive tumor, it is most likely to be successfully treated early in development. For this reason, it is important for the public — but especially medical professionals — to be familiar with the initial warning signs of skin cancer. A melanoma will most likely develop in a region of the skin with a history of sun exposure, such as the back, face or neck. However, melanomas also occur on the palms of the hands, soles of the feet and the fingernail beds. Patients with dark skin are more likely to have hidden melanomas.
Signs of a melanoma include changes in existing moles or development of an unusual growth or a new, pigmented growth on the skin. Melanoma may occur on normal looking skin or may begin as a mole. Typically, a melanoma has a distinct border that separates the lesion from the normal skin surrounding it. These lesions may be oval or sound and are typically smaller than the size of a pencil eraser. Most patients with moles will develop them by age 40. Patients with moles may have somewhere between 10 and 45 lesions. It is important to recognize the characteristics of moles that may indicate a skin cancer such as melanoma.
The mnemonic that patients (and of course medical professionals) should keep in mind to help identify unusual moles is “ABCDE.” This represents:
ASYMMETRICAL SHAPE
BORDER (IRREGULAR)
COLOR CHANGES
DIAMETER (LARGER THAN ¼ INCH)
EVOLVING (CHANGING)
Any mole that bleeds or itches may be a cancerous mole.
Some unusual melanomas include those that form in the eye, causing visual changes; mucosal melanomas that line the membranes of the nose, gastrointestinal and urogenital tract, and those that grown under a fingernail or a toenail (acral lentiginous melanoma.)
The reasons for misdiagnosis of melanoma are not always the same. Some types of melanoma may be misdiagnosed as “melanocytic nevi” or moles — typically by primary care doctors, dermatologists or pathologists. This may be due to lab error, sometimes because large laboratories may receive a number of slides to be read at discounted prices, resulting in an emphasis in rapid turn-around instead of careful correlation with clinical changes and immunohistologic stains. The error may be the result of cost-containment measures. Or the error may be simply the result of careless review by the medical professional.
The consequences of failure to timely diagnosing malignant melanoma can be catastrophic. As everyone knows, the earlier cancer is detected, the better the prognosis in treating the cancer. An unnecessary delay in diagnosis can transform a very easily treatable melanoma into a terminal cancer.
For a free consultation with Passen & Powell to discuss a possible medical negligence, personal injury or wrongful death matter, please call us at 312-527-4500.
