V. Jay et Rl. Font, CONJUNCTIVAL AMELANOTIC MALIGNANT-MELANOMA ARISING IN PRIMARY ACQUIRED MELANOSIS SINE PIGMENTO, Ophthalmology, 105(1), 1998, pp. 191-194
Background: The authors describe an amelanotic malignant melanoma of t
he conjunctiva in association with primary acquired melanosis (PAM) si
ne pigmento, and highlight the clinical and pathologic features of thi
s rare entity. Methods: Histopathologic and immunohistochemical studie
s were performed on a conjunctival tumor in a 54-year-old white woman.
Study Design: Case report. Results: Histopathologic examination revea
led an invasive amelanotic melanoma of the conjunctiva, with anterior
orbital extension arising from intraepithelial dysplastic melanocytes
that lacked melanin pigment (PAM sine pigmento). Both the malignant me
lanoma cells and the intraepithelial dysplastic melanocytes in the are
as of PAM exhibited S-100 and HMB-45 positivity, The patient underwent
an orbital exenteration that disclosed tumor within the anterior orbi
t inferiorly. Conclusions: Amelanotic invasive malignant melanoma can
arise in association with PAM sine pigmento, as seen in our patient wh
o had orbital invasion necessitating exenteration, This aggressive for
m of conjunctival melanoma is often associated with a poor prognosis a
nd risk of metastatic disease, Absence of conjunctival pigmentation in
PAM sine pigmento prevents early clinical detection of this variant o
f PAM, This lack of pigmentation also makes clinical diagnosis virtual
ly impossible, and diagnosis can only be established histopathological
ly, Awareness of this nonpigmented variety of PAM is crucial for early
recognition and appropriate management of the associated melanoma.