Acral melanoma foot lesions. Part 2: clinical presentation, diagnosis, and management

Abstract

Acral melanoma (AM) is a rare subtype of cutaneous malignant melanoma found on acral skin, primarily on the soles of the feet. Although rare, it is the most common subtype of melanoma found in patients of African or Asian ethnicity and has a poor prognosis, often because of the more advanced stage of presentation at diagnosis. In the second of this two-part series, we review the clinical presentation, histopathology, diagnosis and management of AM. Clinically, AM presents as a variegated lesion with blue-black pigment and irregular borders on acral skin. A parallel-ridge pattern is a very specific dermoscopic finding for AM. The differential diagnoses of AM include acral naevus, pyoderma gangrenosum, pyogenic granuloma, verrucous carcinoma and peripheral neuropathy-induced foot ulcers. If there is a clinical suspicion of AM, an excisional biopsy should be taken. Once diagnosis is confirmed by histology, surgical excision is the standard treatment. Overall, dermoscopy and histopathology are key tools in the diagnosis of AM. A greater emphasis on melanoma screening and awareness is essential in minority populations to improve survival outcomes in AM.

Enlarging plaque on the sole

“…Clinically, acral melanomas are rarely amelanotic, appearing as reddish‐pink macules or nodules . Dermoscopy of amelanotic acral melanoma shows remnants of pigmentation and polymorphous vascular pattern . No polymorphous vessels were noticed in our case, nor any pigmentation.…”

“…Amelanotic melanomas present a great challenge in dermatology; however, vessels in amelanotic melanomas are usually dermoscopically easily visualized. Clinically, acral melanomas are rarely amelanotic, appearing as reddish‐pink macules or nodules . Dermoscopy of amelanotic acral melanoma shows remnants of pigmentation and polymorphous vascular pattern .…”

Reliability of patient's anamnesis in the diagnosis of acral melanoma

“…She referred that the lesion appeared about 2 years before, after colliding with a stone (Figure 1a). The dermatoscopic examination showed a central ulceration with blue-black background not following the rete-ridges pattern (Figure 1a AM clinical presentation is very variable, from a flat blackish blue lesion to an amelanotic papule of pinkish color (Desai et al, 2018;Tanioka, 2011), for this reason misdiagnosis is very common ranged from 25 to 36% (Mansur et al, 2016). It is well documented that the F I G U R E 1 (a) Pigmented and ulcerated lesion on the right sole; left frame-dermatoscopic examination showing blue-black background not following the rete-ridges pattern.…”

Completion lymphadenectomy should not necessarily be recommended after a positive sentinel lymph node biopsy

“…We wish to comment on the recent CPD review article on acral melanoma published recently in Clinical and Experimental Dermatology . In our view, the statement (and CME question) ‘recommending’ complete lymph node dissection (CLND) after a positive SLN biopsy, although well intended, is misleading in light of new evidence.…”