Expert Witness Journal Issue 67 June/July 2026 - Flipbook - Page 52
Missed malignant melanoma diagnoses
can lead to severe outcomes and
litigation. Dr Ernest Allan explains
why early excision is critical - and why
relying solely on visual assessment can
be dangerously misleading.
by Dr Ernest Allan, Honorary Consultant Clinical Oncologist.
Litigation as a result of delay in the diagnosis of
malignant melanoma occurs frequently. It may arise
from the failure of the GP, the dermatologist or the
pathologist.
Patients frequently present as the horizontal growth
phase is changing to a vertical growth phase. At this
time no features of malignancy may be apparent.
The Breslow thickness and the presence of lymph
node involvement are the two most important
prognostic features. As the tumour enters the
vertical growth phase the lesion may have a Breslow
thickness of 0.5 mm with a 10 year survival of 95%.
When the Breslow thickness is allowed to progress
to more than 4mm the 10 year survival falls below
50%.
Malignant melanoma may arise de novo as a
small black speck which gradually progresses to a
substantial tumour. Alternatively, and more usually,
it arises from a naevus which may have been present
for many years.
NICE and the BAD have issued guidelines to enable
GPs and dermatologists to identify malignant
melanomas and to di昀昀erentiate them from benign
skin lesions. Members of the legal profession tend to
rely on these guidelines. As a result clinicians either
discharge patients who do not have the characteristic
features of malignant melanomas or keep them on
follow up until the characteristic features develop.
EXPERT WITNESS JOURNAL
For each mm increase in Breslow thickness there is
a 13% increase in the risk of metastatic disease. The
growth rates of Breslow thicknesses are variable but
may be as rapid as 0.5 mm per month during the
vertical growth phase.
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JUNE 2026
