Clinical History
Skin lesion (2 centimeters of the largest transverse diameter) clinically suspected to be a melanoma before surgical reject.
Imaging Findings
Skin lesion (2 centimeters of the largest transverse
diameter) clinically suspected to be a melanoma before
surgical reject.
A morphological sonographic study was performed to analyse the structural
sonographic pattern and to mesure tumor thickness with electronic calipers.
The maximal thickness was determined by measuring from the stratum granulosum to
the deepest point on the posterior margin.
High frequency US scan demonstrates an ovoid hypoechoic tumor with
homogeneous echostructure and well-defined lower and lateral margins.
The tumor measured:
2.60 mm in thickness (20 MHz)
2.72 mm in thickness (13 MHz)
Color Doppler sonography was used to search for intratumoral vessels and
completed by a spectral analysis with determination of the resistive index
(RI = systolic velocity - diastolic velocity / systolic velocity). The low
resistance intra tumor blood flow caracterize the neovascularization.
Color Doppler sonography scan reveal a tumor containing intratumor vessels.
The arterial velocity spectrum shown below the scan was recorded.
The resistive index was low : 0.41
Discussion
Naevus
Current management of melanoma consist in a first surgical
resection based on the clinical features followed in about
30% of cases by re-excision according to the Breslow index
measured at histological analysis.
Surgical margins (according to the french consensus) .must be adapted to the tumor thickness:
a marging of at least 1 cm is required for tumors with a
Breslow index of 1 mm or less, of 2 cm for those with an
index between 1.01 and 4 mm and of 3 cm for those with an
index over 4 mm.
At histologic analysis, the tumor measured 2 mm in
thickness (Breslow index).The overestimation of tumor thickness at US occurrred when a melanoma is developing inside a neavus
Also, Color Doppler is able to evaluate angiogenesis and
pulsed Doppler characterize the tumor vascularisation of
melanoma.
Differential Diagnosis List
Melanoma measuring 2 mm thickness at histological study. Surgical margins (2 cm) was adapted to the tumor thickness.
Final Diagnosis
Melanoma measuring 2 mm thickness at histological study. Surgical margins (2 cm) was adapted to the tumor thickness.
