Eugene C. Toy MD, Donald Briscoe, MD, FA AFP, Bruce Britton, MD, Joel J. Heidelbaugh, MD, FA AFP, FACG
A 45-year-old white woman presents to your office concerned about a "mole" on her face. She says that it has been present for years but her husband has been urging her to have it checked. She denies any pain, itching, or bleeding from the site. She has no significant past medical history, takes no medications, and has no allergies. She has no history of skin cancer in her family. She is an accountant by occupation.
On examination, the patient is normotensive, afebrile, and appears slightly younger than her stated age. A skin examination reveals a nontender, symmetric, 4-mm papule that is uniformly reddish-brown in color. The lesion is well circumscribed, and the surrounding skin is normal in appearance. There are no other lesions in the area.
⯈ What is the most likely diagnosis?
⯈ What features are reassuring of a benign condition?
⯈ What is your next step?
ANSWER TO CASE 13:
Skin Lesions
Summary: A 45-year-old healthy woman with no significant past medical history presents for evaluation of a skin lesion. She does not have a family history of skin cancer. The lesion is symmetric, with well-defined borders, relatively small ( <6 mm), and uniform coloration. She is not able to assess whether the lesion has changed recently (ie, become larger), and does not give a history of itching or bleeding at the site of the lesion.
- Most likely diagnosis: Benign nevus
- Reassuring features: Size less than 6 mm, symmetric, uniform color, well defined borders
- Next step in treatment: Reassurance and surveillance
- Describe an approach to the evaluation of skin lesions.
- Be able to describe the features of a skin lesion in dermatologic terms.
- Know which features of a lesion are typically benign and which are concerning for malignancy or potential malignancy.
Considerations
This case represents a typical scenario seen in primary care medicine: "I have this mole. Is it cancer?" Although simplified, this is what the patient is most concerned about and wants to know. The role of the physician is to determine the likelihood of malignancy or premalignancy and to define a course of action that is appropriate. In this particular case, there are several features that reassure a benign condition that can be monitored without the need for a biopsy. There was neither a family medical history of skin cancer nor history of skin cancer in the patient. She has an occupation that does not expose her to harmful chemicals or the sun on a regular basis. On examination, the lesion has typically benign features (size <6 mm, symmetric, uniform color, well-defined borders). In this case, it would be appropriate to make a note (or possibly even a photograph) in the patient's chart describing the characteristic features of the lesion and monitor for changes in the lesion at periodic health evaluations. The patient should also be educated in self-examination of the skin, with an emphasis on what to look for and when to come to the physician's office for an evaluation of a new or changing skin lesion. Finally, it should be understood that many otherwise benign-appearing moles might have an atypical characteristic that warrants further investigation. The criteria that are used to predict the likelihood of a benign versus malignant lesion are only guidelines, to be sure. Not all malignant skin lesions present in the same manner and a malignant melanoma is not always visibly pigmented. The bottom line is that the physician should use all of the tools at his disposal: the history of present illness (HPI), medical history of the patient, the family medical history (FMH), social and occupational history, and a pertinent review of systems so as to arrive at a conclusion that is consistent with the physical examination.
DEFINITIONS
ABSCESS: A closed pocket containing pus
BULLA: A blister greater than 0.5 cm in diameter (plural: bullae)
CYST: A closed, saclike, membranous capsule containing a liquid or semisolid material
MACULE: A discoloration on the skin that is neither raised nor depressed
NODULE: A small mass of rounded or irregular shape that is greater than 1.0 cm in diameter
PAPULE: A small, circumscribed elevated lesion of the skin that is less than 1.0 cm in diameter
PLAQUE: A plateaulike, raised, solid area on the skin that covers a large surface area in relation to its height above the skin
ULCER: A lesion through the skin or mucous membrane resulting from loss of tissue
VESICLE: A small blister less than 0.5 cm in diameter
CLINICAL APPROACH
Incidence and Risk Factors
There has been an increase in the morbidity and mortality of skin cancer in the past few decades in the United States. American Academy of Dermatology estimates that almost 138,000 new cases of melanoma will be diagnosed in 2015 alone. When you consider nonmelanoma skin cancers, including basal cell carcinoma or squamous cell carcinoma, more than 3.5 million new cases of skin cancer are diagnosed annually. Skin cancers cause approximately 15,000 deaths per year, of which 75% are due to melanoma.
The single most important risk factor for the development of skin cancer is exposure to natural and artificial ultraviolet radiation. It is also one of the only risk factors that can be avoided, and avoiding it can potentially prevent millions of new cases of skin cancer every year. Other risk factors include a prior history of skin cancer, a family history of skin cancer, fair skin, red or blonde hair, a propensity to burn easily, chronic exposure to toxic compounds such as creosote, arsenic, or radium, and a suppressed immune system.
BASIC TYPES OF MELANOMA
Melanoma in Situ
No invasion has occurred in this type of melanoma, as the malignant melanocytes are localized to the epidermis. If diagnosed early, this type of lesion should be excised with 5-mm borders.
Superficial Spreading Melanoma
This is the most common type of melanoma in both sexes. As its name implies, this lesion spreads superficially along the top layers of skin before penetrating into the deep layers. The superficial, or radial, growth phase is slower than the vertical phase, which is when the lesion grows into the dermis and can invade other tissues or metastasize. Men are more commonly affected on the upper torso, whereas women are affected mostly on the legs. Common clinical features include raised borders and brown lesions with pinks, whites, grays, or blues.
Lentigo Maligna
Similar to the superficial spreading type, this lesion is most often found in the elderly (commonly diagnosed in the seventh decade of life), usually on chronic sun-damaged skin such as the face, ears, arms, and upper trunk. Although it is the least common of the four types of melanoma, this is the most common form of melanoma found in Hawaii. They are clinically characterized as tan to brown lesions with very irregular borders.
Amelanotic Melanoma
This is an uncommon ( <5%) melanoma that is nonpigmented and can clinically present as many other types of noncancerous conditions, including eczema, fungal infections, basal or squamous cell carcinoma. Because of its lack of pigmentation, this type of melanoma usually remains undiagnosed until a more invasive stage as compared to other melanomas.
Acral Lentiginous Melanoma
Similar to the other two superficial melanomas in that it begins in situ, this lesion is different in many ways. This is the most common melanoma found in African Americans and Asians. This melanoma is usually found under the nails, on the soles of the feet, and on the palms of the hands; common clinical features include flat, irregular, dark brown to black lesions.
Nodular Melanoma
This melanoma, unlike the others, is usually invasive at the time of diagnosis. This is the most aggressive and second most common type of melanoma (Figure 13-1). They are clinically characterized as mostly black, but occasionally brown, blue, gray, red, or tan lesions that arise from nevi or normal skin.
Figure 13-1. Nodular melanoma. (Reproduced, with permission, from Kasper DL. Brounwold E. Fouci A,
et al. Harrison's Principles of lntemal Medicine. 16th ed. New Yorkl NY: McGraw-Hill; 2005:499.)
PHYSICAL EXAMINATION
In 198S, it was noted by clinicians studying melanoma that there were several characteristic features of skin lesions that con-elated with melanoma. Specifically, color variegation, border irregularity, asymmetry, and size greater than 6 mm in diameter were consistently observed with melanoma. This led to the ABCD acronym, which has been used extensively to determine the likelihood of a cancerous skin lesion (Table 13-1).
One other criterion that is often used is the change in the size or appearance of the skin lesion. This is sometimes cited as E in the above ABCD Criteria, and referred to as Evolving and Elevation. Benign lesions may present at birth, or any time thereafter, and several benign lesions may also present near the same point in time. However, a benign lesion, once present, will usually remain stable in size and appearance, whereas a malignant will present as increasing in size or changing in appearance. Thus, it is useful to ask whether a "mole" has recently changed in appearance or has grown in size.
The "Ugly Duckling Sign" may guide physical examination of skin lesions as it is easy to remember and teach. Simply, as the name suggests, this alludes to the
blatantly different appearance of the melanoma as compared to the other lesions the patient may have.
Another procedure that may aid the detection of melanoma in the family physician's office is dermoscopy. This is a magnification technique by which a skin lesion can be visualized for more detail regarding its pigment and structure. The dermoscopic properties of a lesion may guide the physician's management in terms of either observing its evolution or performing a biopsy to further evaluate it.
TREATMENT
Benign nevi need only be monitored visually. The patient can accomplish this after education on what to look for and when to come back for reevaluation. In general, any preexisting nevus that has changed or any new pigmented lesion that exhibits any of the ABCDE signs should be excised completely with a 2- to 3-mm margin around the lesion. Larger lesions that may be cosmetically difficult to completely excise may be biopsied in several areas. If the pathology indicates a malignancy, the lesion should then be completely excised with 5-mm margins by a physician trained in plastic surgical technique. Complete excision of malignant melanomas requires at least a 5-mm margin. Once a patient has been identified as having a malignant skin lesion, the patient should be observed on an annual basis for any new or changing skin lesions. Shave biopsy may be used for raised lesions, and punch biopsy or elliptical excision for flat lesions. If the entire lesion cannot be removed due to size or location, biopsies should be taken from the most suspicious parts of the lesion.
PROGNOSIS
The single most important piece of information for prognosis in melanoma is the thickness of the tumor, known as the Breslow measurement. Melanomas less than 1-mm thick have a low rate of metastasis and a high cure rate with excision. Thicker melanomas have higher rates of metastases and poorer outcomes.
PREVENTION
Prevention is aimed at reducing exposure to ultraviolet radiation. When possible, avoid the sun between 10 AM and 4 PM; wear sun-protective clothing when exposed to sunlight; wear a sunscreen with a sun protection factor (SPF) of at least 15; and avoid artificial sources of ultraviolet (UV) radiation. Due to the high risk of developing skin cancer in fair-skinned individuals, The United States Preventive Services Task Force (USPSTF) recommends behavioral counseling regarding minimizing exposure to UV radiation to reduce risk of skin cancer (grade B). This recommendation is targeted for age group between 10 and 24 years who are fair skinned. For individuals older than 24, this recommendation currently has insufficient evidence for effectiveness of behavioral counseling.
The USPSTF, however, does not recommend routine screening with whole body examination in the general population for the early detection of premalignant lesions as the evidence of benefit versus harm or routine screening in preventing malignancy is insufficient (grade I). It should be kept in mind that these recommendations are for the general population. Special population including those with family history of skin cancers, prior history of benign or malignant cancer, and other risk factors should be examined and managed appropriately on an individual basis.
NONMELANOMA SKIN CANCERS
Both basal cell and squamous cell carcinomas arise from the epidermal layer of the skin. The primary risk for these types of skin cancers is exposure to ultraviolet radiation, especially sun exposure but also tanning bed use. A history of actinic keratoses and human papillomavirus infection of the skin also raises the risk of squamous cell carcinomas.
Basal cell carcinomas are the most common of all cancers. They typically appear as pearly papules, often with a central ulceration or with multiple telangiectasias. Patients typically present with a growing lesion and sometimes complain that it bleeds or itches. Basal cell carcinomas rarely metastasize but can grow large and can be locally destructive. The primary treatment is excision.
Squamous cell carcinomas have a higher rate of metastasis than basal cell carcinomas, but the risk is still low. These lesions are often irregularly shaped plaques or nodules with raised borders. They are frequently scaly, ulcerated, and bleed easily. Complete excision is the treatment of choice.
COMPREHENSION QUESTIONS
13.1 A 36-year-old man is noted to have a bothersome "mole" that on biopsy reveals malignant melanoma. The pathologist comments that this histology is a very rare type of melanoma and usually escapes diagnosis until a more advanced stage. Which of the following is the most likely finding?
A. Melanoma in situ
B. Superficial spreading melanoma
C. Amelanotic melanoma
D. Nodular melanoma
E. Acral lentiginous melanoma
13.2 A 73-year-old woman presents for concern about several tan-colored moles on her arms, face, and ears that have progressively grown over the past 6 months. Upon further examination, the moles are determined to be between 6 and 8 mm with very irregular borders. The physician decides to obtain an excisional biopsy. Which of the following skin lesions should the physician be most suspicious of based on history alone?
A. Benign nevus
B. Superficial spreading melanoma
C. Lentigo maligna
D. Nodular melanoma
E. Acral lentiginous melanoma
13.3 A 23-year-old Caucasian woman presents to your office for a routine well woman examination. She feels well without any concern/complaints. She is a non-smoker with no significant past medical history. Her last Pap smear with cotesting was last year. Her last tetanus shot was 2 years ago and she has received a flu shot for the current season already. She states that she has never been checked for skin cancer before and asks to be checked for it today. She denies excessive sun exposure and has never been to a tanning facility before. Based on the above information, which preventive services does she need at today's visit?
A. Pap smear and tetanus shot
B. Whole body examination to check for skin lesions based on age and race
C. Tetanus shot only
D. Mammogram and tetanus shot
E. Counseling to avoid excessive sun exposure and tanning booths
13.4 A 45-year-old African-American woman presents for a routine examination. You notice a 9-mm-diameter lesion on the palm of her right hand that is dark black, slightly raised, and has a notched border. When asked about it, she says that it has been present for about a year and is growing. A friend told her not to be concerned because, "black people don't get skin cancer:' Which of the following is your advice?
A. Her friend is correct and this is nothing to worry about.
B. While anyone can get skin cancer, this lesion has primarily benign features and can be safely observed.
C. This lesion is suspicious for cancer but this is most likely a metastasis from another source, such as a breast cancer.
D. This lesion is suspicious for a primary melanoma and needs further evaluation immediately.
13.5 A 70-year-old woman presents for evaluation of a lesion on her left cheek. It has been present for several months. It is slowly enlarging and bleeds if she scratches it. On examination, you find a 7-mm-diameter pearly appearing
papule with visible telangiectasias on the surface. Which of the following is
the appropriate management of this lesion?
A. Close observation and reexamination in 3 months
B. Reassurance of the benign nature of the lesion
C. Excision
D. Local destruction by freezing with liquid nitrogen
ANSWERS
13.1 C. Amelanotic melanoma is an uncommon type of melanoma that due to its lack of pigmentation often goes undiagnosed until it is in a more invasive and advanced stage.
13.2 C. Lentigo maligna is most often found in the elderly usually on chronic sundamaged skin such as the face, ears, arms, and upper trunk. Think of this type with tan-colored lesions on sun-damaged skin that has very irregular borders.
13.3 E. This patient is up-to-date on her cervical cancer screening and immunizations for her age. She is not yet of the age where screening mammography would be recommended. Per USPSTF recommendations, whole body skin cancer screening is not generally recommended but counseling to reduce the risk of development of skin cancer would be advised.
13.4 D. The lesion described is suspicious for an acral lentiginous melanoma and needs evaluation. While skin cancers are more common in persons with lighter skin, they can occur in persons with any skin color or tone.
13.5 C. The lesion is most likely a basal cell carcinoma and should be treated with excision. While the likelihood of metastatic spread is low, these lesions can grow and be locally destructive.
CLINICAL PEARLS
⯈ The preventable risk factor common to all skin cancers is sun exposure. Recommend to your at-risk patients limiting exposure to sunlight in the middle of the day, wearing appropriate protective clothing, and using sunscreen.
⯈ Contrary to popular belief, the use of tanning beds is also a risk factor for skin cancer.
⯈ There is no such thing as a "healthy tan:'
⯈ Clinicians should be aware that fair-skinned men and women older than 65 years, patients with atypical moles, and those with more than 50 moles constitute known groups at substantially increased risk for melanoma.
⯈ Excisional biopsy should be done for any lesion suspicious for melanoma. If the entire lesion cannot be removed due to size or location, full-thickness biopsies should be taken from the most suspicious parts of the lesion.
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