Oral cavity & oropharynx
Other tumors
Oral mucosal melanoma
Author: Nat Pernick, M.D.
Last author update: 1 November 2013
Last staff update: 22 August 2022
Copyright: 2002-2024, PathologyOutlines.com, Inc.
PubMed Search: Melanoma oral cavity
Table of Contents
Definition / general | Prognostic factors | Case reports | Gross description | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Differential diagnosis | Board review style question #1 | Board review style answer #1Cite this page: Pernick N. Oral mucosal melanoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/oralcavitymelanoma.html. Accessed April 25th, 2024.
Definition / general
- Rare; annual incidence of 1.2 cases per 10 million; more common in Japanese, black Africans, Native Americans and Hispanics
- Median age 61 years, 78% men
- Differs from cutaneous melanoma due to lack of association with sun damage, family history or atypical nevi and difference in prognostic factors
- Nodal and distant metastases are common
- References: Am J Surg Pathol 2001;25:782, Am J Surg Pathol 2002;26:883
Prognostic factors
- Extremely poor prognosis, with median survival 2 - 3 years; some lower grade tumors without vascular invasion had median survival of 8 years
- Poor prognostic factors: vascular invasion, polymorphous tumor cell population and necrosis
- No prognostic value: tumor thickness, ulceration and level of invasion
Case reports
- 17 year old girl with tender lesion of hard palate (Arch Pathol Lab Med 2002;126:1110)
- 47 year old man with tumor after low dose radiation therapy for lichen planus (Arch Pathol Lab Med 1985;109:290)
- 71 year old man with multiple firm left submandibular swellings for two months (Case #419)
Gross description
- Mucosa covering maxillary bone (62%), labial mucosa (13%) and lower gingiva (8%)
- Usually flat, erythematous or pigmented, less commonly presents as a mass
Microscopic (histologic) description
- Mean 3 mm thick; pigmented or frequently amelanotic; morphology includes epithelioid, fusiform and polymorphous cells
- Some tumor giant cells in almost all cases; 90% have associated melanoma in situ; usually mitotic figures
- Frequent ulceration, necrosis, vascular invasion and perineural invasion; may have desmoplastic features, particularly if lower lip
Microscopic (histologic) images
Case #419
Nests and nodules
of tumor cells with
melanin pigments
Tumor cells with
extensive necrosis
and melanin
pigments
PAP
HMB45 (cell block)
Giemsa
Positive stains
- S100 (97%), tyrosinase / T311 (94%), MelanA / Mart1 / A103 (85%), microphthalmia associated transcription factor / MITF (D5, 74%) and HMB45 (71%)
- Desmoplastic melanoma: S100, tyrosinase
Negative stains
Differential diagnosis
- Amelanotic melanomas:
- Large cell lymphoma, poorly differentiated carcinoma
Board review style question #1
What do primary mucosal melanoma and cutaneous melanoma have in common?
- Both commonly have BRAF mutations
- Both use the same staging criteria
- Sun exposure is a risk factor for both
- They have a similar prognosis
- They have the same immunohistochemical profile
Board review style answer #1
E. They have the same immunohistochemical profiles. Primary mucosal melanomas share histologic and immunohistochemical features with cutaneous melanomas but differ in terms of risk factors, aggressiveness, molecular profiles and staging criteria.
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Reference: Melanoma
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Reference: Melanoma
