The first is that the nevus will recur in the scar years later and be indistinguishable from melanoma--the so-called pseudomelanoma phenomenon.
It could also be the case of pseudomelanoma phenomenon where it's a nevus to start with but it comes back looking more atypical, so it's incorrectly diagnosed as melanoma.
In 1975, Kornberg and Ackerman (6) reported that pigmented RN could closely resemble superficial spreading malignant melanoma (SSMM), both clinically and histologically, and proposed the term pseudomelanoma to describe this benign phenomenon.
The clinical appearance of pseudomelanoma was described as variegated pigmentation, with jet-black foci resembling SSMM; the authors (6) suggested that this change resulted from scattering of melanocytes through the stratum corneum.
In 1986, Trau et al (7) reported a case of pseudomelanoma after C[O.
Park et al (3) concluded that RN with atypical features rarely resembled SSMM, thereby posing "significant diagnostic difficulties," but added that most RN did not mimic melanoma histologically; therefore, they did not recommend the term pseudomelanoma.
Given the rarity of RN cases that seem indistinguishable from melanoma, the term pseudomelanoma, although established in the literature, seems applicable to at best a small minority of RN, and in our view is best eschewed.
Pseudomelanoma following laser therapy for congenital nevus.
Recurrent melanocytic nevi after Solcoderm therapy: a new cause of pseudomelanoma.
Pseudomelanoma due to hypermature cataract can be identified using USG by the presence of an echodense cortex forming anterior and posterior borders, lack of contiguity with the uvea, and ring melanomalike visibility in all four quadrants.
Ciliary body and choroidal pseudomelanoma from ultrasonographic imaging of hypermature cataract in 20 cases.