Hypomelanotic melanoma

Remnants of brown-gray color in association with polymorphous vessels and pink color should raise the suspicion of hypomelanotic melanoma. The diagnosis of amelanotic and hypomelanotic melanoma is one of the greatest challenges in dermatology because only a few, if any, of the well-known features of melanoma are present, due to the lack of melanin. One variant of hypomelanotic melanoma has light brownish or other lightly colored melanin pigment that may occupy the entire lesion area. Vascular structures are the key clues for identifying hypomelanotic melanoma, and only a few papers dealing with the vascular architecture within melanoma have been published so far. While in amelanotic melanoma vessels are the only clues for diagnosis, in hypomelanotic melanoma remnants of melanin pigment are usually clearly recognizable under the dermatoscope. Morphology of vessels in melanoma undergoes time-dependent changes during tumor growth. Thin melanoma is supplied by dotted vessels in a quite regular arrangement across the entire tumoral area.