Metastatic Melanoma



Clinical History: 
This 36-year-old patient presented in December 2006 with a suspicious mole on the right lower leg which was surgically removed. Histopathology demonstrated a malignant melanoma.
2.5 years later the patient presented with an inguinal lymph node metastasis on the right side detected on lymph node dissection. MRI was ordered to further evaluate the right leg on which additional cutaneous lesions were noted.

Malignant melanoma with inguinal and subcutaneous metastases.

MR Technique: 
Scans were acquired on a 32-channel 1.5 T Siemens MAGNETOM Avanto system using a time-resolved MRA-technique with view-sharing (TWIST, time-resolved MRA with interleaved stochastic trajectories, TR/TE 2.94/0.91 msec, voxel size 1.7×2.3x3mm³ with a temporal resolution of 3 sec per 3D-data set, parallel imaging GRAPPA factor 2) after bolus injection of 14 ml of a 0.5 M formulation of a gadolinium chelate at 1.5 ml/sec. No bolus timing was performed. The sequence was started 5 sec before the contrast agent was administered to allow for a non-enhanced mask frame. The scan parameters for the T1w TSE coronal post contrast with fat sat were TR/TE 594 msec/11 msec with a voxel size of 1.2×1.2×4 mm³.

Imaging Findings:
There are numerous subcutaneous enhancing lesions within the right lower leg which are visualized due to their hypervascularity on the contrast enhanced MRA. Due to the large number of metastases, there is increased blood flow to the entire right leg.