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Choroidal Melanomas With a Collar-Button Configuration
Response Pattern After Iodine 125 Brachytherapy
Dennis M. Robertson, MD
Arch Ophthalmol. 1999;117:771-775.
Objective To describe a distinctive type of postbrachytherapy response pattern among choroidal melanomas with a collar-button configuration.
Methods Ninety-three consecutive eyes with choroidal melanoma treated with iodine I 125 brachytherapy before 1991 were reviewed to identify melanomas with a collar-button configuration. Postbrachytherapy response patterns of these melanomas were reviewed.
Results Thirty-four of the 93 eyes contained tumors with a collar-button configuration. Sixteen (47%) of the 34 eyes demonstrated a postbrachytherapy response pattern characterized by persistence of the collar-button, while the body of the tumor demonstrated shrinkage. During follow-up, the color of the collar-button configuration changed from light brown to dark chocolate (16 [47%] of 34 eyes). Subsequently, irregularly clumped, darkly pigmented debris was observed to slough from the surface of the collar-button configuration into the vitreous cavity (7 [21%] of 34 eyes). The debris was comprised largely of pigment-laden macrophages in 1 eye in which a vitrectomy was performed. In another eye, histopathologic study of spherical clusters of intravitreal brown-colored debris identified malignant melanoma cells.
Conclusions A distinctive postbrachytherapy regression pattern of melanoma with a collar-button configuration has been identified. The main body of the tumor shrinks, whereas the collar-button configuration persists, appears more prominent, gradually changes to a darker color, and may then shed pigmented debris into the vitreous cavity. This pigmented debris may be composed of pigment-laden macrophages and/or melanoma cells. Clinical characteristics of the vitreous debris may help distinguish malignant invasion by melanoma cells from infiltration by nonmalignant debris and macrophages.
From the Department of Ophthalmology, Mayo Clinic, Rochester, Minn.
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