Genital lentigines and melanocytic nevi with superimposed lichen sclerosus: a diagnostic challenge

Benign pigmented lesions of the genitalia, such as genital lentigines and melanocytic nevi, often show clinical and histopathologic features highly suggestive of malignant melanoma (MM). Superimposed changes of lichen sclerosus (LS) may cause real concern and lead to an erroneous diagnosis of MM.

This study was performed to assess clinicopathologic characteristics of genital lentigines and melanocytic nevi with associated LS.

We performed a retrospective review of 5 cases.

Histopathologic sections of the 2 cases of genital lentigines with concurrent changes of LS showed a lichenoid lymphocytic infiltrate and pigment incontinence with melanophages in a fibrosed papillary dermis, features reminiscent of completely regressed MM. The 3 cases of genital melanocytic nevi and superimposed LS were sharply circumscribed, relatively symmetric, but revealed confluent nests varying in size and shape and pagetoid upward spread of melanocytic nests and single melanocytes. Changes of LS extended beyond the melanocytic proliferation.

Genital lentigines and melanocytic nevi with associated LS may show features that mimic MM.