Introduction:

Melanoma is a malignant melanocytic tumor that constitutes the sixth most frequent cancer in the general population and has a high capacity to produce metastasis.

Approximately 95% of primary melanomas belong to four clinicopathological types: extensive superficial, nodular, lentigo maligna, and acral lentiginous. The remaining 5% correspond to less frequent variants, among which is amelanotic melanoma, that represents between 0.4-27.5% of the cases in this subgroup.

Objective:

To present a case of an amelanotic melanoma, as a variant that can accompany any other clinical type of melanoma, in this case a nodular type, a lesion that, due to its decrease or absence of pigment, can lead to diagnostic errors that affect the delay in treatment and reduce the survival of patients who suffer from it.

Clinical Case:

The case of a 75-year-old male patient who presents with an exophytic tumor lesion on the forehead of approximately one year of evolution.

Physical examination reveals a bright, erythematous, dome-shaped tumor which shows a polymorphous vascular pattern with a predominance of thick linear vessels under a polarized light dermatoscope.

Several differential diagnoses are proposed, among which the following stand out: basal cell carcinoma, pyogenic granuloma, lymphoma, and skin metastases; a sample is taken for biopsy and staining techniques with immunohistochemistry, which confirm the diagnosis of melanoma, it is decided to excise the tumor with margins and multidisciplinary follow-up of the case.

Conclusions:

The hypo / amelanotic variants of melanoma are rare and their diagnosis presents difficulties that usually generate delays that influence the treatment and prognosis of the disease. Dermoscopy is presented as an extremely useful tool that can increase the diagnostic suspicion of these tumors, although the histopathological study continues being the gold standard for diagnosis, as well as for the therapeutic approach and subsequent follow-up.