Immunohistochemical studies of CCSTA show that the tumor cells express antigens associated with melanin synthesis including diffuse cytoplasmic immunoreactivity with HMB-45 (Figure 3), nuclear and cytoplasmic immunoreactivity to S100 protein (Figure 4), and reactivity with the microphthalmia transcription factor.
The EWSRI gene rearrangement has been detected in 70% to 90% of CCSTA. (3,9,10-17,24) Conventional cytogenetic analysis of tumor tissue requires fresh tissue for cell culture, whereas reverse-transcriptase polymerase chain reaction analysis can be performed on fresh, snap frozen tissue for RNA extraction, as well as with paraffin-embedded tissue.
In contrast to CCSTA, paraganglioma-like dermal melanocytic tumor is primarily a tumor of the extremities of females, presents as a dermal nodule, and is composed of clear to amphophilic oval cells of low nuclear grade arranged in a packetlike fashion reminiscent of a paraganglioma.
Treatment of CCSTA involves wide excision of the tumor as soon as the diagnosis is established.