Fluorescent in situ hybridization (FISH): A useful diagnostic tool for childhood conjunctival melanoma

Abstract

Introduction: Conjunctival melanoma is extremely rare in children and has low rates of resolution. Definitive histopathological diagnosis based exclusively on microscopic findings is sometimes difficult. Thus, early diagnosis and adequate treatment are essential to improve clinical outcomes. Clinical case: We present the first case in which the fluorescent in situ hybridization (FISH) diagnostic technique was applied to a 10-year-old boy initially suspected of having amelanotic nevi in his right eye. Based on the 65% of tumor cells with 11q13 (CCND1) copy number gain and 33% with 6p25 (RREB1) gain as measured by the FISH analysis, and on supporting histopathological findings, the diagnosis of conjunctival melanoma could be made. Following a larger re-excision, adjuvant therapy with Mitomycin C (MMC), cryotherapy and an amniotic membrane graft, the patient has remained disease-free during 9 years of long-term follow-up. Case discussion: Every ophthalmologist should remember to consider and not forget the possibility of using FISH analyses during the differential diagnosis of any suspicious conjunctival lesions. Genetic techniques, such as FISH, have led to great advances in the classification of ambiguous lesions. Evidence-based guidelines for diagnosing conjunctival melanoma in the pediatric population are needed to determine the most appropriate strategy for this age group.

The 5th Edition of the World Health Organization Classification of Tumours of the Eye and Orbit

“…Tumors of the Conjunctiva and Caruncle (Table 3) This chapter provides an update on pathogenesis and molecular genetics of melanocytic conjunctival lesions (Table 4) [2,[8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]. Spitz nevus is removed from this chapter because of the lack of molecularly welldocumented cases of this tumor in the conjunctiva.…”

“…This chapter provides an update on pathogenesis and molecular genetics of melanocytic conjunctival lesions (Table 4) [2, 8–27]. Spitz nevus is removed from this chapter because of the lack of molecularly well-documented cases of this tumor in the conjunctiva.…”