Spontaneously Regressing Primary Nodular Melanoma of the Glans Penis
Primary malignant melanoma (PMM) of the penis is rare. However, regression of PMM is not rare. The authors report a case of complete clinical regression of a nodular, mucosal, penile PMM with no evidence of metastatic disease.
The prognostic significance of melanoma regression is controversial. Regression may be mediated by host immunity, apoptosis, and/or antiangiogenesis. The lymphocytic infiltrate in regressive melanomas consists of cytotoxic T cells with selective antitumor activity, which induces HLA class I–restricted melanoma lysis.8 Lymph node migration may result in T-lymphocyte priming and induction of antitumor immunity.9 Therefore, regression may indicate risk for sentinel LN metastasis.
It is possible that complete regression of melanoma does not truly exist, and late recurrence due to cancer dormancy is inevitable. Late recurrence is defined as first metastasis 10 years after complete removal of the PMM.10 Our patient has only been followed for 8 years, so this possibility cannot be entirely excluded.
