Rare presentation of eczema-like amelanotic melanoma of the forearm with its dermoscopic differentiation

Thin amelanotic melanomas could be described as great masquerades as they may imitate inflammatory diseases (e.g. psoriasis, eczema), skin neoplasms (Bowen disease, basal cell carcinoma), actinic keratosis or Spitz nevi. What is more, these diagnostic difficulties refer to both small and large lesions. The only chance for the clue of melanoma in such cases can arise after dermoscopic examination. Dermoscopy is a valuable tool for the diagnosis of pink or non-pigmented skin lesions, which was proved by numerous previously published studies [1].
We present a rare case of amelanotic melanoma in the form of a pink and brown macule with fine desquamation of its surface (Figure 1 A). The lesion was localized on the right forearm of a 65-year-old female. Even though it has been present for a few years, despite a few dermatological consultations, the suspicion of melanoma has never arisen. Dermatological examination revealed a multicomponent pattern composed of symptoms of neoangiogenesis with the presence of multiple polymorphic vessels, regression with the occurrence of multiple black dots, multiple grey and brown dots and slate globules with areas resembling lichen planus-like keratosis at the periphery. White structureless areas in the centre of the lesion and slight scaling and remnants of the pigment at the periphery were seen (Figures 1 B–D). Due to the suspicion of melanoma, the lesion was totally surgically excised and the histological examination confirmed the diagnosis of melanoma in situ. One year later a 73-year-old female was referred by a GP to our clinic for a routine skin examination. A pink and grey macule was present on her left forearm (Figure 1 E). The patient could not recall for how long she had it, but confirmed that the lesion had changed within last year. The dermoscopic examination revealed a multicomponent pattern composed of symptoms suggesting solar lentigo with the presence of a honey-comb pattern at the periphery, fine disrupted reticulate light brown pigmentation and regression presented as dispersed, grey dots on the pink background (Figures 1 F–H). The suspicion of regressed melanoacanthoma was proposed but due to the occurrence of the extensive area of regression the whole lesion was excised. The histological examination confirmed the primary diagnosis of solar lentigo. A 45-year-old female patient was examined due to the presence of an asymptomatic, solitary pink, rounded macule with a rough scaling surface (Figure 2...


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