• Clinical science

Uveal melanoma

Abstract

Uveal melanoma is the most common primary malignant tumor of the eye. It develops from choroidal melanocytes and is therefore often pigmented. The tumor can arise from the choroid, iris, or ciliary body. Symptoms, which depend on the location of the tumor, begin when the tumor extends to the optical axis or if there is concomitant retinal detachment or interference with the function of the ciliary body or pupil. The condition is diagnosed through fundoscopy and ultrasonography. Treatment usually consists of radiation therapy or surgical removal of the tumor in advanced disease. With the exception of iris melanoma, uveal melanoma is typically diagnosed late because of the lack of early symptoms. Approximately half of patients go on to develop distant metastases via hematogenous spread, most commonly to the liver, which are then fatal.

Epidemiology

  • Incidence: 6–10/1,000,000 per year
  • Peak incidence: 50–70 years
  • More common in individuals of Northern European descent and those with light eye and/or skin color
  • Location:

Epidemiological data refers to the US, unless otherwise specified.

Etiology

Clinical features

Diagnostics

  • Fundoscopy
    • Nodular, dome-shaped subretinal mass
    • Traits that are more likely to be found in melanomas than benign nevi :
  • Additional tests
    • Ultrasonography
    • Fluorescein angiography
  • Staging

Pathology

  • Cytology
    • Spindle-shaped cells: best prognosis
      • Type A → thin nucleus and no visible nucleoli
      • Type B → large nucleus and visible nucleoli
    • Epithelioid melanoma: poor prognosis
      • Large polygonal cells and prominent nucleoli
    • Intermediate cells: similar to epithelioid cells, but smaller
  • Histopathology
    • Mixed-cell melanoma, which includes variable proportions of the three cell types, is the most common form (> 85% of cases).
    • Tumor cells with a bundle-like arrangement, which may have brown intracellular melanin in some areas

Differential diagnoses

The differential diagnoses listed here are not exhaustive.

Treatment

  • Observation: for small, asymptomatic tumors
  • Radiation therapy
    • Brachytherapy
      • Iodine-125 (gamma rays)
      • Ruthenium-106 (beta rays)
    • Charged-particle radiation therapy
      • Indicated in circumpapillary lesions (i.e., lesions encircling the optic nerve)
  • Enucleation : in advanced findings
  • Transpupillary thermotherapy

Complications

We list the most important complications. The selection is not exhaustive.

Prognosis