However, mimics of melanoma (eg, pagetoid Spitz nevus, spindle cell nevus
of Reed) should be carefully considered before a small lesion is diagnosed as melanoma.
When significant pigment is present in a spindled nevus, the diagnosis of pigmented spindle cell nevus
of Reed is often appropriate (likely representing a Spitz variant).
In most cases, the histologic differential diagnosis was between Spitz nevus and spitzoid melanoma or between atypical nevus (such as variants of deep penetrating/clonal/inverted type-A nevus, pigmented spindle cell nevus
, atypical genital nevus, atypical conjunctival nevus showing cytologic atypia, mitotic activity, limited maturation, or proliferative nodules, among others) and nevoid melanoma (Table 1).
The histological spectrum of pigmented spindle cell nevus
: a review of 120 cases with emphasis on atypical variants.
Most variants of cutaneous nevi including combined nevus, balloon cell nevus, Spitz nevus, pigmented spindle cell nevus
, and blue nevus have been reported in the conjunctiva.
PEH Associated With Underlying Neoplasms.--When it represents a reaction to subjacent neoplasms, epidermal PEH is principally seen in conjunction with granular cell tumor, dermatofibroma, xanthogranuloma, dermatofibrosarcoma protuberans, or melanocytic proliferations, such as Spitz nevus and spindle cell nevus
of Reed (21-26) (Figure 2, A and B).