Pigmented Skin Lesions (Case 34)

Chapter 42
Pigmented Skin Lesions (Case 34)

James G. Bittner IV MD, Joan R. Johnson MD, MMS, and D. Scott Lind MD

Case: A 68-year-old woman presents with a pigmented skin lesion on her right thigh.

Differential Diagnosis

Basal cell carcinoma (BCC)	Atypical nevus
Squamous cell carcinoma (SCC)	Actinic keratosis
Malignant melanoma	Benign nevus

Speaking Intelligently

When asked to see a patient who presents with a pigmented skin lesion, we start by asking the patient what she thinks the lesion may be and reassuring her that as a team we will “find out” the answer. This allows us to quickly assess the patient’s level of concern regarding the pigmented skin lesion. Next, we find out when she first noticed the lesion; if it has changed in shape, size, or color; whether or not it is painful; and whether the patient noticed any similar lesions recently or in the past. We also ask whether the lesion has been itching or bleeding and whether she has had any prior biopsies, laboratory tests, or imaging studies ordered by other physicians. It is important to ask about a prior personal or family history of skin cancer.

PATIENT CARE

Clinical Thinking

• Most patients think cancer first (perhaps rightfully so), and they want an answer—yesterday. That said, it is up to you, the physician, to reassure the patient that the ideal scenario is a correct diagnosis based on clinical, radiographic, and pathologic evidence. A timely but inaccurate answer may result in lost credibility, increased patient anxiety, and a strain on the physician-patient relationship. Most of all, you don’t want to miss a skin cancer. Therefore, if a lesion is suspicious, you should perform a biopsy. If a biopsy is required, be sure to check the patient’s history for coagulopathy or medications that might cause bleeding such as clopidogrel, aspirin, and warfarin.

• Different pigmented skin lesions present differently. It is very important to understand the natural history and clinical presentation of malignant melanoma. In other words, when the history and physical exam are equivocal, consider melanoma and evaluate accordingly.

• Any patient who presents with a skin lesion should be offered education about the sources and hazards of ultraviolet radiation as well as the importance of sun-safe behaviors.

History

It is crucial to obtain a thorough history, including past medical history, family history (especially including skin cancers), surgical history, and medications; of particular interest are the following skin cancer risk factors:

• Age and gender: Forty-five percent of men with melanoma have trunk or back lesions, while 42% of women have lower extremity lesions. In addition, women with melanoma have an improved survival rate compared to men (82% 10-year survival compared to 61% 10-year survival in stage I disease).

• Skin and hair color: Fair-skinned people, especially with blond or red hair, are more likely to develop melanoma.

• Skin history: Is there a history of severe sunburns (especially as a child), tanning bed exposure, or previous melanomas? Bullous skin disease and decubitus ulcers or other nonhealing wounds or ulcers all have an increased risk of becoming malignant. When these lesions become cancerous, they are referred to as Marjolin ulcers.

• Anatomic location: Melanoma limb lesions have a better prognosis than head/neck or trunk lesions (82% compared to 68% overall survival rate).

• Occupation: Patients with prolonged ultraviolet exposure are at increased risk.

• Location: Persons who spend a significant amount of time in areas of the world that receive more sunlight are at increased risk.

• Chemical carcinogens: Exposures to tar, arsenic, nitrogen mustard, and soot are significant risk factors.

• Radiation: History of industrial, therapeutic, and occupational exposure constitutes high risk.

• Medications: Topical acne medications may predispose to skin sloughing, and anticoagulants may affect surgical planning.

• Immunosuppression: Patients with HIV, AIDS, and patients on chronic immunosuppression, such as solid-organ transplant patients, are at increased risk of developing malignant skin lesions.

Physical Examination

• Most patients with a skin lesion present with normal vital signs.

• A complete skin examination in a well-lighted room includes inspection from the scalp to the toes, paying careful attention to those areas most notable for harboring cutaneous malignancies such as the face, neck, upper back, upper and lower extremities, and dorsal and ventral aspects of the hands and feet.

• Document the anatomic location, size, shape, color (pigmentation), presence or absence of ulceration, blanching, bleeding, or evidence of inflammation. A photograph of the lesion can also be helpful. Benign pigmented lesions such as freckles should be followed for increased melanoma risk.

• When evaluating a patient with a pigmented skin lesion, the findings of Asymmetry (one half of the lesion is different from the other half), Border irregularity, variegated Colors (multiple colors such as black and blue), larger Diameter (>5 mm), and Evolution (change in size, color, or erythema, onset of pruritus, and ulceration) raise the suspicion for malignancy (ABCDE of melanoma). You need only one of these findings for the lesion to be concerning.

• A rigorous search for palpable lymph nodes is a must. Pay close attention to the path of lymphatic drainage particular to the skin involved.

Tests for Consideration

• CBC: Useful to evaluate for preoperative thrombocytopenia or anemia if surgery is considered.	$11
• PT/INR and PTT: Help with procedural planning in patients taking anticoagulants or those with potential coagulopathy.	$15
• Punch biopsy: A 6-mm punch biopsy is appropriate for small (<5 mm) benign-appearing lesions that will be entirely removed or for larger lesions (2 cm or more) that will require wide local excision. Do not perform a shave or partial-thickness biopsy, because depth of invasion is the most important prognostic feature.	$105
• Excisional biopsy: This type is preferred for all malignant-appearing lesions at least 5 mm in diameter where complete excision is possible. A full-thickness biopsy is obtained to determine depth of invasion. Care must be taken to orient the incision in a fashion compatible with future wide local excision.	$310
• Wide local excision: Every primary malignant melanoma requires wide local excision to decrease the risk of loco-regional recurrence. Current recommendations for excision margins are:	$580
• Lesion ≤ 1 mm in depth, excise 1-cm tumor-free margin. • Lesion 1.01–2 mm in depth, excise 1- to 2-cm tumor-free margin. • Lesion 2.01–4 mm in depth, excise 2-cm margin. • Lesion > 4 mm in depth, excise 2- to 3-cm margin.
• Sentinel lymph node biopsy: This is an accurate, minimally invasive method for staging patients with malignant melanoma. The sentinel node(s) is the first or principal site of lymphatic tumor spread to the nearest basin draining the affected skin.	$570

IMAGING CONSIDERATIONS

→ Chest radiograph: Performed for preoperative evaluation and to evaluate for pulmonary metastases if melanoma is diagnosed.	$45
→ CT scan: When melanoma depth of invasion is >4 mm or ulcerated >2 mm, palpable lymph nodes are present, and/or symptoms suggest metastatic disease, a CT scan of the chest, abdomen, and pelvis should be performed.	$334
→ PET scan to evaluate for metastases. It can be combined with regular CT scan to more precisely localize metastatic lesions if clinically indicated.	$1037
→ CT/PET of chest, abdomen, and pelvis if melanoma depth is >2 mm with ulceration or >4 mm without ulceration.	$1037