Persistent Melanoma with a Striking Well Differentiated Neural Component

Abstract

Although neurotropism and focal neural differentiation are fairly common in the setting of desmoplastic and spindle cell melanoma, in situ melanoma exhibiting a significant well differentiated neural component is very rare. We report the case of a 70 year old man with persistence of melanoma at the site of excision of a melanoma in situ of lentigo maligna type. The patient presented three years later noting thickening of the skin at the site of his previous surgery. Scar revision led to the unexpected identification of underlying melanoma with a marked and striking neural component. Obvious melanoma was noted in the epidermis and dermis, along with a deeper spindle cell component that exhibited routine histologic and immunopathologic features of a well differentiated neural tumor. If not for the gradual transitions and continuity of these components, a second bystander tumor would have been considered. Without the ample specimen received, misdiagnosis would have been likely. We review phenomenon of neural differentiation with our unusual illustrative case.