Acral lentiginous melanoma

Case contributed by Ali Alsmair
Diagnosis almost certain


Left big toe mass under the nail, with proven histopathology of acral lentiginous melanoma.

Patient Data

Age: 55 years
Gender: Female

An irregularly-shaped soft tissue lesion in the dorsal aspect of the big toe, immediately under the nail bed. Cortical irregularity and subcortical mild reactive bone marrow edema in the dorsal aspect of the distal phalanx which shows enhancement, indicating the involvement of the distal phalanx by the lesion. The extensor tendon attachment at the base of the distal phalanx is likely involved.

The interphalangeal joint of the big toe seems not to be involved. The proximal phalanx is clear. The flexor tendon attachment is not definitely involved.

These changes are consistent with the known acral lentiginous melanoma.

Case Discussion

Acral lentiginous melanoma is melanoma of the hands and feet. 'Acral' derives from the Greek word 'acros', meaning highest point or extremity. 'Lentiginous' means that the lesion initially appears as a brown macula resembling lentigo, a benign cutaneous lesion composed of melanocytes.

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