How to Avoid the Missed Diagnosis of Melanoma

Raising awareness among patients, primary care professionals, and specialists
July 2015, Vol 3, No 7 - Inside Dermatology Care
Richard P Usatine, MD

Even though melanoma is the third most common skin cancer,1 it is the deadliest type, claiming more lives yearly than any other skin cancer.2

Although basal-cell carcinomas are far more common than melanomas, they rarely metastasize and, therefore, are rarely fatal.3 Alternatively, melanoma can metastasize and be rapidly fatal within months of diagnosis.4 Most melanomas, however, start off growing slowly, and can be detected early to prevent fatalities.2 There are many different types of melanoma, each with its own appearance and prognosis.5 The deadliest type is nodular melanoma, which tends to grow fast and deep, and metastasizes early.4 Fortunately, the most common type is superficial spreading melanoma, which tends to spread laterally for years before spreading vertically.5 It is the vertical growth that leads to spreading of the disease to the lymph nodes, and to metastases.

As more patients are receiving their healthcare in retail clinics and asking their pharmacists for health advice, it behooves the providers in these settings to recognize suspicious lesions and make appropriate referrals to dermatologists. Counseling about skin cancer prevention in these settings is also a valuable service as there is clear evidence that most skin cancers come from sun exposure and tanning beds.

Patient Evaluation

Any person presenting to a pharmacist with a skin lesion should be sent to their primary care physician or dermatologist for evaluation. In general, skin lesions are at a higher risk for cancer when they are growing rapidly, have ulcerated, or cause pain and itching.6 Any new, pigmented lesion in an adult requires expert evaluation. Common, benign, pigmented lesions include solar lentigo, seborrheic keratosis, and dermatofibroma. Seborrheic keratoses (ie, age spots) are usually pigmented, with a verrucous surface, and appear to be stuck on the skin.7 However, a seborrheic keratosis can look like melanoma and melanoma can look like a seborrheic keratosis.6 Therefore, it is important that a medical professional trained in the diagnosis of melanoma examines the patient.

The state-of-the-art method for examining a patient with a suspicious skin lesion involves the use of a dermatoscope. The dermatoscope is placed on or near the skin, and magnifies the skin tenfold while providing a bright light for better visualization.8 Most dermatoscopes today use polarized light and a cross-polarized filter so that the viewer can see deeper into the skin. This depth of view allows for more accurate diagnoses. For example, seborrheic keratoses have many recognizable features that are especially visible with a dermatoscope and differ from the specific features of melanoma. The dermatoscope can help differentiate between a benign nevus, pigmented basal-cell carcinoma, and melanoma.

All new dermatologists are required to learn dermoscopy and many primary care providers are now learning this valuable technique. As a teacher of dermoscopy workshops to primary care providers, I have seen the growth interest in dermoscopy mushroom over the past few years. The providers in retail clinics should consider learning dermoscopy if they plan to expand their services to include skin cancer screenings.

Visual and Surgical Methods for Detecting Melanoma

The ABCDE (ie, asymmetry, border irregularity, color variations, diameter >6 mm, and evolution) method of detecting melanoma is a good start, but is insufficient for the diagnosis of all melanomas.

Nodular and amelanotic melanomas may only have a single color, and may not be asymmetric or have varying border characteristics.5 However, virtually all melanomas have features recognizable with dermoscopy. Some of the more challenging melanoma diagnoses include the amelanotic melanoma that does not have visible pigment, and the acral lentiginous melanoma found on hands and feet.6 Amelanotic melanoma may present as a pink bump or scaling ulcerated lesion that resembles a nonmelanoma skin cancer.8 The use of a dermatoscope can detect features that are suspicious for melanoma, and avoid a missed diagnosis.

Because treatment can be planned better when the diagnosis has been confirmed histologically, any patients with new, suspicious lesions need a biopsy and confirmed diagnosis before receiving definitive treatment. For example, freezing a suspected nonmelanoma skin cancer prior to histologic diagnosis could result in the incorrect treatment of melanoma.

Acral lentiginous melanoma is found particularly on the palms of the hands, soles of the feet, and around fingernails.1 There are some melanomas that are subungual (ie, under the nail); these may present as a dark line under the nail, and can lead to nail destruction.9 It is not uncommon for a nail with subungual melanoma to have a previous history of trauma to the nail unit. Therefore, a nonhealing nail injury should receive a biopsy to make sure that it is not melanoma. Also, melanomas around the nail have been misdiagnosed as paronychia (ie, ingrown nails or nail-fold infections).

Avoiding Missed or Delayed Diagnoses

These 2 avoidable medical errors led to missed or delayed diagnoses of melanoma:

  1. Performing cryosurgery on a lesion for which the diagnosis is not 100% certain. It is best to avoid freezing what appears to be a benign nevus because it could be melanoma, or when the nevus grows back a future biopsy may appear to look like melanoma.6 Most importantly, cryosurgery is not an appropriate treatment for melanoma, and freezing an early-stage melanoma may give it time to spread deeply and metastasize before it is properly diagnosed.
  2. Throwing away pathology specimens after excision or biopsy. All pigmented lesions should be sent for histologic examination after excision or biopsy. Even a seborrheic keratosis that appears benign should be sent to the pathologist when excised. The only lesions that can safely be discarded include nonpigmented skin tags, typical sebaceous cysts, and typical lipomas.6

    I recently reviewed a malpractice case in which the physician discarded a lesion thought to be a seborrheic keratosis, and their patient presented with metastatic melanoma years later. This was especially problematic because the original lesion was growing rapidly, bleeding intermittently, and causing itching. As was mentioned earlier, these are all risk features of melanoma, so discarding the excised lesion was not appropriate.

The Necessity of Dermoscopy

I encourage all clinicians caring for a patient’s skin to learn and use dermoscopy. Diagnosing skin lesions today without a dermatoscope is similar to diagnosing ear problems without an otoscope. Although not all skin lesions require a dermatoscope, its use in trained hands has been proved to increase diagnostic accuracy.

Any clinician interested in learning dermoscopy can attend courses, or learn from journals, books, applications, or websites. See the Resources below for a list of resources that you can use to extend your clinical skills to include dermoscopy. Through greater awareness of the dangers of excessive sun exposure and early melanoma detection we can save lives.


  1. Gohara M, Perez M. Skin Cancer and Skin of Color. Skin Cancer Foundation website. Accessed June 15, 2015.
  2. The Skin Cancer Foundation. Melanoma. Skin Cancer Foundation website. mation/melanoma. Accessed June 15, 2015.
  3. The Skin Cancer Foundation. Basal Cell Carcinoma (BCC). Skin Cancer Foundation website. Accessed June 15, 2015.
  4. Erkurt MA, Aydogdu I, Kuku I, et al. Nodular melanoma presenting with rapid progression and widespread metastases: a case report. J Med Case Rep. 2009;3:50.
  5. University of California, San Francisco. Melanoma. Accessed June 19, 2015.
  6. Karnes J, Usatine R. Melanoma. In: Usatine R, Smith M, Mayeaux EJ, Chumley H, eds. Color Atlas of Family Medicine. 2nd ed. New York, NY: McGraw-Hill; 2013.
  7. Kahan S, Miller R, Smith EG. In A Page Signs & Symptoms. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2008:308-309.
  8. Marghoob AA, Usatine RP, Jaimes N. Dermoscopy for the family physician. Am Fam Physician. 2013;88:441-450.
  9. Patel GA, Ragi G, Krysicki J, Schwartz RA. Subungual melanoma: a deceptive disorder. Acta Dermatovenerol Croat. 2008;16:236-242.


Dermoscopy Resources to Extend Your Clinical Skills

Applications Books & Journal Articles
  • Johr RH, Stolz W. Dermoscopy: An Illustrated Self-Assessment Guide. New York, NY: McGraw-Hill Education; 2010.
  • Marghoob AA, Usatine RP, Jaimes N. Dermoscopy for the family physician. Am Fam Physician. 2013;88:441-450.
Meetings & Workshops Websites
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Last modified: August 20, 2015
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