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Choroidal naevus Choroidalnaevi are prcsent in 5-10%of Caucasians but are veryrarein dark-skirmed races. They can beassociated with NF1and the dysplastic naevus syndrome. Although they are probablypreient at birth, growth occurs rnainiy during the prc-pubertalyears and is extremelyrare in adulthood. For this reason clinjcally detectable growLh snouro arouse susPrclon oI ma[8nanc], Histo!ogy Thetumoul is composed oI a Plolileration of spindlecell melanoc)'tes (Fit. 12.21A). S,gns 1. Pr€s€ntatifi. The vast rnajority of naevi are asympto- _ matic and detected by routineexamination. Rarely s).mptoms may be caused byinvolvemmt ofih€fovea by thetumowitrelf or by serous rctinal detachment. 2. Signe of a tlaical naevui . Usually pogt-equatodal, oval or circular, brown to slate-grey lesion with hdistinct martins (Fig. 12.218). . Dimensions are <5 mm in basal diam€te (i.e.3 disc diameters) and <1rnmthickneso. . Surface drusmfilay bepresent, particularly in the cmtralarea of a larger lesion fFig. 12.21C). . Secondary choroiid neovaicularizatronrs . Typical naevi donotrequle follow-up because the rbk of malignant transformation i6extremely low. lnvestigations l. Photogaphy as a baseline record is good practice. 2, FA findings depmd on the amouit;f pismentation within $e nie\,us and associated change; fr the over- lyinS RPE. Most nievi are avascdar td pigmented, dving rise to h)pofluorescence caused by bl6ctr ageof backgound choroidai fluorescence. U rhe lesio; ;s associated with surface drus€nand RPE detachment, thb wiu tesult in areas oI ht?erfluorescence (Fit. 12.21DJ. fA is not helpftrt in d;stinguish;g a smail melaromafrom a naerls a-lrhough ;dtiple-pinpoini ar€as ol h)?e uorescnce muypieai.t tui*.gt6"rtr. 3. ICCA showshypofluorescmce relative to the sur- rouidins choroid (Fig. 12.21E). 4. Ulhasonogaphy tUS) shows alocalized nat or slightly elevated lesionwith hith internal acoustic reflecivi{' (Fig. 12.21F). Atypical naevus . An amelanotic naevus (Fis. 12.22,4). . A'halo'naevu( whichisiurollnded bv a pale zone resembling chorcidatatrophy (Fig. 12.ZiB).' Susplcrous naeyus 1, Clinicalf€atu.res. The foUowint suy sugSest thdt a me anoc) fi. test on isnot.naenrs but asnrall melanonra. . Documented growth. . s].rnproms su(h ,s blurred vision. meraftorphop. sra/ nerd toss and photoDsja. . P,ll:jl:* .5 mm in diameter d1d >r mrr h Traces of surface orante pigment 0jpofuscin). Aosence or su ace ctrusen on a thicklesion. Margrn of the lesion at or near th€ optic disc T1:!r, *1.,r d."rg.tr:"r eflher over rhe swfaLe of the lesionor inJeriody. P"^f^"jj:ijry.lTE "f these.fearues, the hisher th€ chance ihat the lesionis a melanoma. lf growth has been docummted, the lesion be reclassified as a melanoma aird accordin8ly. Dlffercntial diagnosis 1, Congenital hyperirophy o{ th€ RpE is dark and with a well defined ourline. MarLaffmenl invoheE basellne fundu3 phorograDh! ano urnasonogaphy, anct ften indefinjLe fol;wi,f, 2. Melanoct'tomn of the choroid is clinicalh I guishable ftom a larte naelars. 3. Smrll melanoma is associated with serous detachmmt and clumps of orange pigment. Chorcldal melanoma Choroidal melanoma has anovemll incidence of5-7 million?er year in westem hemisphere countdes signficant gender difference. It js the most ( primary inhaocular maljgnancyin adults and Ior 80%of all uveal melanomas'. Pathology 1. CeI ttTE a. Spmdlecells are aranged in tight bundles; cell membra-nes areindistincr anA the cl'roDlt a coarse chromatinDaftemand Dromin€nt oli. Mitotic figues are more ftequent ttEri, spindle cells (Fig. 12.238). 2, Clae6iffcation of uveal melanomas. a, Spindle .ell melanomas fomredexclusively spindle cells. b. Mited cev fielarcIJ.asin which thereis a of spindle ard epithelioid ce s. 3. Ofher histological featu€s L Fascicularpaften of cell Fowth which may vasocentic in whjch the cells are arrar$d t pendicular to a cmtsdl vess€' fi8. l2.23(t thillary or finelygranular. Nuclel'vaiy slmderto pludrp and nucleoli may or may distinct [Fig. U.AA). b, Epithelioid cells arelarg€rand morc pleotr thanspindle ceUs, often;ppeafinq polihedr abundant eosinophilc cyiopt*.. ni" c"tl banes are distinct and an eihacellular space separates adjacent cells.The nuclei are larye dbbon-1ile
