Letter to the Editor
Melanoma of unknown primary origin coexisting with early-onset multifocal basal cell carcinoma

Skin is the most common localization of primary melanoma, however in 2–6% of patients a metastasis of melanoma without a detectable primary tumor is found [1]. This is referred to as melanoma of unknown primary origin (MUP). It usually presents as cutaneous or subcutaneous nodules or lymph node metastases [2]. The theories concerning the etiology of MUP include the presence of a melanoma that was misdiagnosed and excised without the further histopathological examination, a regressed melanoma; or a primary nodal melanoma connected with malignant transformation of a nevus cell in a lymph node or other non-skin tissue. In support of the last two theories, in melanomas a partial spontaneous regression connected with immunological mechanisms frequently occurs, moreover ectopic melanocytes may be found in lymph nodes and the other tissues, being a potential reservoir of the cells, which may undergo a neoplastic transformation [2]. In patients with MUP metastases may be found primarily in the skin, subcutaneous tissue, internal organs, bones and brain [1]. In more than 50% of MUP cases, similarly to sporadic melanomas with a known primary origin, a mutation of the gene encoding kinase protein BRAF (V600E) is found. The coexistence of melanoma with the other skin cancers may be connected with the presence of genes encoding the factors regulating the cell cycle, e.g. p53 protein.
A female patient with metastasis of melanoma to the lymph node of the right groin of unknown primary origin, with a coexistence of three basal cell carcinomas is presented in the report.
A 33-year-old female patient, generally healthy, with a positive history of drug abuse in the past, presented with a few centimeters’ large, painless nodule within the right inguinal region. Ultrasound examination revealed a longitudinal tumor, partly solid and partly polycystic with vascularized septa. The nodule was surrounded by the capsule and revealed no features of infiltration of the adjacent tissues (Figure 1). Histopathological examination of an excised lesion showed the presence of nodal tissue with the metastasis of melanoma with HMB45 positive, S-100 positive, Melan-A positive, V-9 positive, MIB-1 (a proliferation marker which recognizes the Ki-67 antigen) locally positive (Figures 2 A, B). Keratin AE1/AE3, CG30 and leucocyte common antigen (LCA) were negative in neoplastic cells. There was no history of any surgically excised melanocytic or pigmented lesions. The patient declared...


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