Patients’ workup

Whether patients are being evaluated for the first time or seen in referral from a primary care physician, a thorough patients’ workup begins with a complete history of exposure to risk factors and the lesion in question. Patients should be assessed for sun exposure in early childhood, episodes of severe sunburn, or a personal and family history of cutaneous malignancy. Patients should also be questioned about the nature of the lesion, specifically whether there has been a recent change in the last few weeks or months, or if there are symptoms, such as bleeding, itching, pain, or ulceration.

Certain characteristics of skin lesions may indicate a process consistent with melanoma; the acronym “ABCDE” highlights some features of cutaneous lesions that have a high likelihood of being melanomas: Asymmetry, Border irregularity, Color variegation, Diameter greater than 6 mm, Evolution.

When dealing with melanoma, a complete physical examination includes careful palpation of the nodal basins draining the area: the preauricular, parotid, postauricular, suboccipital, posterior cervical, anterior cervical, and supraclavicular nodal groups. If clinical lymphadenopathy is present, further imaging, such as a CT scan, MRI, ultrasound, or fine-needle biopsy may be indicated.

Types of melanoma

The most common type of melanoma is superficial spreading, which represents 70% of the cases of melanoma diagnosed in the head and neck.

Nodular melanoma represents 15% to 30% of all cases of melanoma and may easily be mistaken for hemangioma, blue nevi, pyogenic granuloma, or a pigmented basal cell carcinoma.

Lentigo maligna, also known as intraepidermal melanoma or melanoma-in situ, is a precursor to melanoma. Lentigo maligna disease represents a diagnostic dilemma as atypical junctional melanocytic hyperplasia, so adequate margins may be difficult.

Desmoplastic melanoma features abundant collagen and has features consistent with fibromas. There is a high tendency for perineural spread in these lesions. Although this histologic variant represents a small percentage of melanomas throughout the human body (1%), it is overrepresented in the head and neck, where 75% of all desmoplastic neurotropic melanomas are found. Furthermore, many of these lesions are amelanotic and thereby make diagnosis difficult.

Mucosal melanoma is a rare, distinct, and separate entity from cutaneous melanoma and should be considered as such. Similar to desmoplastic melanoma, it represents a small portion of overall melanoma subtypes, but nearly half of those diagnosed are found in the head and neck. The nasal cavity is the most common site, specifically the anterior septum, followed by the inferior and middle turbinates. The oral cavity is the second most common site, followed by the larynx.

Types of melanoma

The most common type of melanoma is superficial spreading, which represents 70% of the cases of melanoma diagnosed in the head and neck.

Nodular melanoma represents 15% to 30% of all cases of melanoma and may easily be mistaken for hemangioma, blue nevi, pyogenic granuloma, or a pigmented basal cell carcinoma.

Lentigo maligna, also known as intraepidermal melanoma or melanoma-in situ, is a precursor to melanoma. Lentigo maligna disease represents a diagnostic dilemma as atypical junctional melanocytic hyperplasia, so adequate margins may be difficult.

Desmoplastic melanoma features abundant collagen and has features consistent with fibromas. There is a high tendency for perineural spread in these lesions. Although this histologic variant represents a small percentage of melanomas throughout the human body (1%), it is overrepresented in the head and neck, where 75% of all desmoplastic neurotropic melanomas are found. Furthermore, many of these lesions are amelanotic and thereby make diagnosis difficult.

Mucosal melanoma is a rare, distinct, and separate entity from cutaneous melanoma and should be considered as such. Similar to desmoplastic melanoma, it represents a small portion of overall melanoma subtypes, but nearly half of those diagnosed are found in the head and neck. The nasal cavity is the most common site, specifically the anterior septum, followed by the inferior and middle turbinates. The oral cavity is the second most common site, followed by the larynx.

Risk factors

Risk factors for melanoma of the head and neck are commonly associated with sun exposure, specifically intermittent sun exposure, fair complexion, elevated geographic latitude, and number of lifetime sunburns. Although numerous studies have tried to identify particular patterns of sun exposure that may carry higher risk for developing melanoma, they have failed to display consistent definitions and are subject to recall bias.

Given its numerous deleterious effects on the skin, it is not surprising that sun exposure is a risk factor for developing melanoma. Intermittent sun exposure or an increased number of lifetime sunburns predispose individuals to melanoma formation. Intermittent sun exposure tends to occur on unprotected skin, which penetrates to the melanocytes in the basal layer of the epidermis, whereas repeated exposure of thickened, darkly tanned skin may be effectively blocked by the superficial layers of the epidermis.

Principles of biopsy of a suspicious lesion in the head and neck

The importance of the initial biopsy cannot be overstated. It is essential that every effort be made to perform an excisional biopsy, or at the very least, a large, representative, full-thickness sample of a large, suspicious lesion. Compromise of the biopsy is particularly common in the head and neck because of the many esthetic and functionally important structures in the area. In a study by Austin and colleagues, from M. D. Anderson Cancer Center, a retrospective analysis of 159 melanoma subjects who had a median follow-up of 38 months was reviewed and matched for stage of disease, ulceration, location, thickness, and mode of biopsy. They found that 31% of subjects who had an incisional biopsy died of disease, whereas only 8.9% of the excisional group died of disease. This study suggests that the mode of biopsy of cutaneous melanomas of the head and neck may influence the clinical outcome. However, these findings remain controversial; regardless of failure to perform an excisional biopsy, biopsy loses important prognostic information. With this fact in mind, the physician performing the initial biopsy should consider the following principles:

• 1.
  

  Excisional biopsy with 1 to 3 mm margins is preferred, taking care to avoid wide margins that might interfere with the subsequent lymphatic mapping.

  
  
• 2.
  

  Shave biopsy may compromise pathologic diagnosis and measurement of thickness, thereby forcing the treating surgeon to potentially submit patients to more surgical morbidity because of the uncertainty of the actual thickness of the primary.

  
  
• 3.
  

  If a punch biopsy is necessary because of location, it should be performed in the thickest portion of the lesion.

  
  
• 4.
  

  The specimen must be interpreted by someone who is experienced in interpreting pigmented lesion diagnosis.

  
  
• 5.
  

  The specimen must not be submitted for frozen section because this distorts cells, making definitive diagnosis difficult. The specimen should be submitted only for permanent section.

Management of the primary lesion

The mainstay of the initial treatment of melanoma has always been surgical, reserving radiation, chemotherapy, immunotherapy, or combinations of these adjunctive therapies for metastatic disease or prospective studies following a rigid protocol. As in other areas of the body, the treatment of the primary tumor is wide local excision with the margin dictated by its thickness. In the head and neck, there are many esthetically and functional sensitive structures.

There have been several prospective studies that provide the primary basis for the current recommendations for wide excision of melanomas up to 4 mm of thickness. In situ disease should receive between 0.5 to 1 cm margins, with nodal observation, recent studies would suggest more generous margins controlled with staged excisions. Thin lesions (<1 mm) should be widely excised with a 1 cm margin, whereas intermediate thickness (1–4 mm) would require no more than a 2 cm margin. Lesions greater than 4 mm thick may occasionally need wider margins, although this is a point of controversy in the literature. Reconstruction of the defect from a primary excision is usually accomplished by applying basic principles of surgical reconstruction, using a local flap or a full thickness skin graft (FTSG).

Special locations, such as the ear, should have 1 or 2 cm margins, depending on the thickness of the primary. These margins can be closed primarily when on the helical rim of an otherwise normal-shaped ear. When located in the concha, the cartilage is the deep margin and a FTSG can be placed directly on the underlying dermis, producing a satisfactory esthetic result.

Mucosal melanomas, only 1% of all head and neck melanomas, develop more frequently in the nasal cavity and paranasal sinuses and less often in the oral cavity. Patients present with epistaxis, nasal obstruction, or polyposis with or without pigmentation. Melanoma of the paranasal sinuses are discovered at a more advanced stage. Nodal metastases are distinctly uncommon (<6%) in mucosal melanomas. Surgery is the keystone of therapy, but is frequently augmented with radiation.

An unknown primary is defined as a melanoma that is first identified by its regional, nodal disease (70%) or a distant site (30%). Approximately 10% of head and neck melanomas present in this fashion. These melanomas are thought to have developed from a primary that has since regressed or overlooked. When diagnosed, an exhaustive systemic search should be made for the primary. If found, it is treated as noted earlier in this discussion, but if not uncovered, standard staging is performed and patients are treated as similar staged patients who have a known primary.

Management of lentigo maligna can present a conundrum to the surgeon because of its unpredictable, subclinical extension of atypical disease well beyond the visible margins of the tumor. The work of Neuburg and Jejurikar has given us new insight into the treatment of this common variant of melanoma in the head and neck.