The patient was a 81 year old male with dermoscopically suspicious recently changing pigmented lesion on the forearm. Clinical diagnosis of a nevus was favored and shave biopsy was performed to confirm a clinical impression of a benign nevus.
The biopsy revealed an unsuspected invasive melanoma arising in a nevus invading to a depth of 0.8 mm (Clark’s level II). The subsequent re-excision showed melanoma in situ spreading within dermal eccrine ducts and glands. Two separate foci of syringotropic invasion by single melanoma cells were identified in the proximity of subcutaneous eccrine glands expanded by melanoma at the depth of 3.2 mm (Clark’s level V).
How this lesion should be staged?