Mucosal Melanoma Samantha Hauff

Epidemiology Make up about 10% of all H&N melanomas Make up about 1% of all melanomas More aggressive behavior  15% 5-yr survival Aside from H&N, can occur in GU tract or anus Usually affect ages 60s-80s More common in Japan (usually oral cavity)

Etiology Melanocytes = cells that contain the pigment melanin Located in basal layer of epidermis, mucosa and eyes Derived from neural crest cells Chemical and physical stimulation are known to causer hyperproduction of melanin, causing pigmented lesions Sun exposure is not a risk factor; inhalants may be a risk factor Melanocytes in the nasal upper aerodigestive tract Septum Inferior and middle turbinates Respiratory epithelium Funtion is unknown

Clinical Presentation Nasal cavity most common: Anterior nasal septum Middle turbinate Inferior turbinate Typically p/w unilateral nasal obstruction and/or epistaxis Oral cavity less common: Palate Gingiva Typically p/w painless mass, frequently with bleeding

Differential Oral nevi Melanotic macule Amalgam tattoos Melanoacanthoma

Oral Nevi Fairly rare (prevalence = 0.1%) More common in patients with darker skin tones May be precursors to malignant melanoma

Melanotic macule Usually on the vermillion No malignant potential

Amalgam Tattoos Blue-black discoloration due to deposition of amalgam during dental procedures Much more common than macules and nevi

Melanoacanthoma Reactive process Can develop/spread quickly

Workup Usually appears to be a violaceous, almost polypoid, friable mass Biopsy: inject local  if significant bleeding from injection site, do biopsy in OR given risk for severe epistaxis Imaging: CT with contrast, +/- MRI with gad

Immunostains Mucosal melanomas will typically be positive for S-100 HMB-45 NK1/C-3 Antivimentin Recall that cutaneous melanoma usually positive for: Mart1 Melan-A

Staging No widely accepted staging system (per medscape) Stage I = localized disease Stage II = regional spread Stage III = distant mets NCCN guidelines T3 – mucosa only T4a – cartilage and/or bone involvement T4b – very locally advanced (skull base, dura, brain, lower CNs, masticator space, carotid, prevertebral space, mediastinum) Starts at stage III T3N0  stage III T4aN0 stage IVa T4aN1  stage IVa T4banyN  stage IVb M1  stage Ivc

Treatment Surgical excision with negative margins Neck dissection for cN+ disease Sentinel LN biopsy has not been studied Better local control with adjuvant RT (26% vs 62% in one study) Likely not improved survival Chemo and immunotherapy not frequently used unless palliative

NCCN Guidelines Nasal cavity/paranasal sinuses All other mucosal sites Stage III – resection +/- RT Stage IVa-b – resection + RT All other mucosal sites Stage III – resection + SND +/- RT Stage IVa – resection + SND + RT