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10 derm mistakes you don’t want to make

Patient care can suffer—or be delayed—by these common mistakes. Here’s how to avoid them

Defiance Clinic, Defiance, Ohio
foxgary@yahoo.com

I’ve seen my share of missed diagnoses over the years while caring for patients who, through physician- or self-referral, have made their way to our multi-specialty group practice where I focus solely on skin.

There was the 93-year-old patient whose “sun spot” had been evaluated and treated by 2 different dermatologists in the past and turned out to be a lentigo maligna melanoma (FIGURE 1).

There was the patient who had a lesion on her lip for “at least 10—maybe 20—years” that neither caught the attention of her physician, nor her dentist (FIGURE 2). Histology showed she had an infiltrative basal cell carcinoma.

And then there was the wife of a healthcare professional who decided she wanted a “second opinion” for the asymptomatic lesion on her leg that her husband assured her was benign. Her diagnosis was not so simple: She had a MELanocytic Tumor of Unknown Malignant Potential (MELTUMP) that required careful follow-up (FIGURE 3).

Early detection, as we all know, is the name of the game when it comes to skin malignancies. Yet every day, opportunities to catch small, early lesions are missed.

During the past couple of years, I’ve had thousands of patient visits for skin problems and diagnosed more than 1000 skin malignancies. The majority of patients have had some treatment for their presenting dermatosis prior to arrival. Based on my experiences with these patients, I’ve developed a list of common dermatology “mistakes.” Here they are, with some tips for avoiding them.

  Mistake #1: Not looking (and not biopsying)

I had a woman come into the office to have a lesion assessed. She had seen a dermatologist a couple of weeks earlier and even had a number of lesions removed during that visit. The patient told me that she’d repeatedly tried to show the dermatologist one specific lesion—the one of greatest concern to her—just below her underpants line, but the physician was in and out so fast each time, she never had the chance to point out this one melanocytic, changing lesion.

The lesion turned out to be a dysplastic nevus with severe architectural and cytologic atypia. This type of lesion requires histology to differentiate it from melanoma, and could just as easily have been a melanoma.

Almost daily I treat patients who are being seen by their primary care physicians regularly, and have obvious basal cell carcinomas (BCC) or squamous cell carcinomas. I have even found skin malignancies on physicians, their spouses, and their family members.¹ These lesions can be easily missed—if you don’t look carefully.

Consider, the following:

• FIGURE 4 illustrates a superficial BCC on the forearm of a physician who was totally unaware of it. (It was detected on “routine” skin examination.)

• FIGURE 5 illustrates a BCC on a patient’s central forehead that, by her history, had been there for many years, and was not of any concern to her. The patient was referred to our office for evaluation of itchy skin on her legs.

• FIGURE 2 illustrates a lesion that, according to the patient, had been on her lip for at least 10—and perhaps even 20—years and was of no concern to her. (It was not the reason for the visit.) Over the years, this patient certainly had numerous primary care and dental visits, but no one “saw” the lesion. Histology confirmed the clinical impression of BCC.

  Mistake #2: Using insufficient light

As a former family practice academic, I used to preach to residents that they needed to use “light, light, and more light” for evaluation of skin lesions. Despite this, I was often asked to evaluate a patient with a resident who hadn’t even bothered to turn on a goose-neck lamp for illumination.

Even with my current “double bank” daylight fluorescent examination room lighting, it often takes additional (surgical-type) lighting to see the diagnostic features of skin lesions. Without such intense light, it is often impossible to see whether there is pearliness, rolled edges, or fine telangiectasia.

  Mistake #3: Using insufficient (or no) magnification

I was once examining a patient in a hospital room that had inadequate light, despite my best efforts. So I took out my digital camera with flash and autofocus feature and photographed the lesion. I then looked at the lesion on the camera’s LCD monitor and determined that it was a BCC.

The benefit of the camera was 2-fold: Not only did the flash serve as an instant source of light, but the macro feature also provided magnification. Viewing a magnified digital image on a computer screen also allows unhurried, self “second opinions,” where details can often be ascertained that were not immediately apparent in “real time,” such as rolled edges, telangiectasia, dots, streaks, and subtleties of color.

  Mistake #4: Assuming that pathology is a perfect science

Most physicians assume that dermatopathologists have a high rate of interrater concordance with diagnoses such as melanoma. Unfortunately, that is not always the case. Consider the following:

• As part of a National Institutes of Health consensus conference on melanoma, 8 dermatopathologists considered experts in melanoma were asked to provide 5 slides each. The slides were relabeled and sent to the same 8 dermatopathologists. (Three slides were eliminated.) Their findings: At the extremes, 1 pathologist called 21 cases melanoma and 16 benign, whereas another called 10 melanoma, 26 benign, and one indeterminate.² (Remember: These were all experts in melanoma.)

• In a study of 30 melanocytic lesion specimens (including Spitzoid lesions), 10 Harvard dermatopathologists evaluated each sample independently of each other. Given 5 diagnostic categories to choose from, in only one case did as many as 6 of the 10 agree on a diagnosis. In all of these cases, there was long-term clinical follow-up, so the biologic behavior of these lesions was known. Some lesions that proved fatal were categorized by most observers as benign (eg, Spitz nevi or atypical Spitz tumors). The converse, reporting benign lesions as melanoma, also occurred.³

So consider this: If this degree of discordance occurs among dermatopathologists, what results could we expect from non-dermatopathologists?

I have personally seen instances where reports of melanoma from non-dermatopathologists did not even report Clark and Breslow staging information (although one could determine Clark staging from reading the body of the report), and reports of dysplastic nevi that were accompanied by recommendations for re-excision with 1 cm margins.

When I have a report from a general pathologist suggesting a potentially worrisome lesion (melanoma, severely dysplastic nevus, [atypical] Spitz nevus), I always suggest to my patients that we get a dermatopathologic second opinion. (I send all my dermatopathology specimens to dermatopathologists, so this applies to patients referred in with prior pathology in hand.)

Sometimes, even the dermatopathologists do not agree on the nature of the lesion. In such cases, I have my “MELTUMP discussion” with patients. That is, I tell patients that we don’t know for sure what it is, and that ultimately only the final lab test—time—will tell us the true nature of the lesion (FIGURE 3).⁴

  Mistake #5: Freezing neoplasms without a definitive Dx

“We’ll freeze it and if it doesn’t go away, then…”

This approach poses a significant risk to you (medicolegally) and your patient.

While most of the time what I see has been inappropriately frozen first by first-line providers, that is not always the case. Dermatologists also fall into this trap. FIGURE 6 shows a lesion just behind the hairline on the frontoparietal scalp that was frozen by a very good, and reputable, dermatologist. The patient came to me for a second opinion with an “obvious” BCC.

Some clinicians are “thrown off” when a lesion (like the one on this patient) has hair. Some sources⁶ indicate that BCCs never have hair, but this is patently untrue.

  Mistake #6: Treating psoriasis with systemic corticosteroids

Plaque psoriasis can, albeit uncommonly, be transformed to pustular psoriasis after the administration of oral or injectable systemic corticosteroids.⁷ Although this rarely occurs, most experts consider this poor practice and not worth the risk. In addition, some experts note that systemic glucocorticoids are a drug trigger for inducing or exacerbating psoriasis.⁸

  Mistake #7: Doing shave biopsies on melanocytic lesions

For a melanoma, not only can shaving part way through the vertical dimension of the lesion interfere with staging, it can also hinder the pathologist’s ability to arrive at the correct diagnosis.⁹

  Mistake #8: Using corticosteroid/antifungal combination products

Corticosteroid/antifungal combination products are generally shunned by dermatologists, although they are used extensively by nondermatologists.⁹ The difficulty with a preparation like Lotrisone, which contains a class III corticosteroid (betamethasone dipropionate [Diprosone]) and the antifungal clotrimazole, is that it is often used long-term for presumed fungal infection on thin-skinned areas. Unfortunately, though, chronic use in these areas can lead to atrophy and striae (FIGURE 7).

Additionally, corticosteroid is essentially “fungus food.” Majocchi’s granulomas can form because the corticosteroid interferes with clotrimazole’s antifungal effect. Note also that these combination products can suppress fungus sufficiently to render cultures and KOH preparations falsely negative and alter the clinical appearance of psoriasiform dermatitis, interfering with subsequent, accurate diagnosis.

  Mistake #9: Corticosteroid underdosing and undercounseling

It’s not uncommon during the warm weather months for me to see patients who are near finishing a Medrol Dosepak that was prescribed by their primary care physicians for a case of contact dermatitis (eg, poison ivy). They come to me because the eruption has returned and it is “as bad as ever.”

Underdosing. Medrol Dosepaks are generally underpowered (too low a dosage) and too short a course.^7,10,11

Undercounseling. Patients don’t always realize that contact dermatitis may actually last for 3 weeks or longer. They may also mistakenly believe that systemic treatment will get them through the whole episode (rather than the worst part).

  Mistake #10: Requiring red flags in both history and exam

Skin diagnosis is an “or” game—not an “and” game. By that I mean: If either the history (eg, rapid change, bleeding, crusting, nonhealing ulcer) or the examination is worrisome, biopsy. Even dermoscopy can be completely reassuring with biopsy yielding a melanoma.¹² Note, too, our earlier examples of patients with suspect examinations who gave reassuring histories of lesions that had been present for many years. Either a worrisome history or a suspect examination is sufficient for concern. Remember, in general, the worst-case scenario from a biopsy is a scar; from a missed melanoma, an autopsy report.

Disclosure

The author reported no potential conflict of interest relevant to this article.

References

1. Fox GN, Mehregan DR. A new papule and “age spots.” J Fam Pract 2007;56:278–282.
2. Farmer ER, Gonin R, Hanna MP. Discordance in the histopathologic diagnosis of melanoma and melanocytic nevi between expert pathologists. Hum Pathol 1996;27:528–531.
3. Barnhill RL, Argenyi ZB, From L, et al. Atypical Spitz nevi/tumors: lack of consensus for diagnosis, discrimination from melanoma, and prediction of outcome. Hum Pathol 1999;30:513–520.
4. Elder DE, Xu X. The approach to the patient with a difficult melanocytic lesion. Pathology 2004;36:428–434.
5. McBroom HM, Ramsay AD. The clinicopathological meeting. A means of auditing diagnostic performance. Am J Surg Pathol 1993;17:75–80.
6. Johr R, Soyer HP, Argenziano G, Hofmann-Wellenhof R, Scalvenzi M.  Dermoscopy: The Essentials. New York, NY: Mosby; 2004.
7. Habif TP.  Clinical Dermatology: A Color Guide to Diagnosis and Therapy. 4th ed. New York, NY: Mosby; 2004.
8. Wolff K, Johnson RA, Suurmond D.  Fitzpatrick’s Color Atlas and Synopsis of Clinical Dermatology. 5th ed. New York, NY: McGraw-Hill; 2005.
9. Edwards L.  Dermatology in Emergency Care. New York, NY: Churchill Livingstone; 1997.
10. Brodell RT, Williams L. Taking the itch out of poison ivy. Postgrad Med 1999;106:69–70.
11. Hall JC. Dermatologic allergy. In: Hall JC, ed. Sauer’s Manual of Skin Diseases. 9th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2006:82.
12. Braun RP, Gaide O, Skaria AM, Kopf AW, Saurat JH, Marghoob AA. Exclusively benign dermoscopic pattern in a patient with acral melanoma. Arch Dermatol 2007;143:1213–1215.

Correspondence Gary N. Fox, MD, 1400 E 2nd St, Defiance, OH 43512; foxgary@yahoo.com

The Journal of Family Practice ©2008 Quadrant HealthCom Inc.