Eye
Conjunctiva
Melanoma

Author: Nat Pernick, M.D. (see Authors page)

Revised: 30 April 2018, last major update April 2014

Copyright: (c) 2004-2018, PathologyOutlines.com, Inc.

PubMed Search: Melanoma [title] conjunctiva [title]

Cite this page: Pernick, N. Conjunctiva: melanoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/eyeconjmelanoma.html. Accessed July 21st, 2018.
Definition / general
  • #2 malignancy of conjunctiva after squamous cell carcinoma
  • 2% of ocular malignancies, 5% of ocular melanomas
  • Due to primary acquired melanosis, nevi (20 - 30%) or no apparent precursor lesion (18 - 25%)
  • Usually fair complexioned individuals age 40+ years
  • Be wary of diagnosis in children as it is very rare (J Pediatr Ophthalmol Strabismus 2007;44:277)
Epidemiology
  • 0.012 cases/100K in US, 0.024/100K in Sweden, 0.052/100K in Denmark
  • Rare in blacks
Prognostic factors
  • Excellent if small, localized and bulbar
  • Intermediate if diffuse and bulbar
  • Poor prognostic factors:
    • Fornix, caruncle, plica semilunaris or palpebral conjunctiva
    • Tumor thickness > 4 mm
    • Epithelioid cells or 5+ mitotic figures / 10 HPF (Br J Ophthalmol 1994;78:252)
  • Prognosis not related to nature of initial lesion, although acquired melanosis cases are often multicentric
Clinical features
Case reports
Treatment
  • Complete excision or radical surgery, depending on extent of disease
  • Cryotherapy for margins and base
  • Also topical mitomycin C
  • Recommended to avoid incisional biopsy (Trans Am Ophthalmol Soc 2000;98:471)
Clinical images

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Pigmented lesion
adjacent to primary
acquired melanosis

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Elevated melanotic nodule

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Large neglected melanoma

Gross description
  • Vascular, pigmented, nodular
Gross images

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Large heavily pigmented nodule covers cornea

Whole mount images

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Exophytic tumor covers conjunctiva and cornea

Microscopic (histologic) description
  • Invasion of atypical melanocytes into epithelial connective tissue
  • Usually thin surface epithelium
  • Bizarre polygonal epithelioid cells with eosinophilic cytoplasm, large atypical nuclei, prominent eosinophilic nuclei
  • Also spindle cells, smaller cells, balloon cells containing lipid
  • Often lymphocytes at base or tumor margins
  • Report: presence of primary acquired melanosis or nevi, presence of pagetoid spread at edge of excision, atypical intraepithelial melanocytes, nevus cells; also tumor thickness from surface of lesion to deepest margin using calibrated micrometer
Microscopic (histologic) images

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Nodular tumor at limbus

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Anaplastic melanocytes within epithelial nests

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Pigmented epithelioid cells with prominent nucleoli

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Pleomorphic tumor cells

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Malignant spindled melanocytes

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Malignant epithelioid melanocytes



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Ocular melanoma - site unspecified

Cytology images

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FNA of parotid metastasis

Positive stains
Negative stains
  • Keratin (may be focally positive in epithelioid cells), EMA
Differential diagnosis
  • Extension of extraocular melanoma
  • Metastatic melanoma: clinical history of melanoma, more circumscribed, no intraepithelial tumor
  • Spindle cell carcinoma