56-year-old male with right lower extremity swelling and muscular mass visualized on right lower extremity vascular Doppler examination. There is a large mass in the posterior compartment of the calf which is predominantly situated between the gastrocnemius and soleus muscles. There is an additional component extending anteriorly between the tibia and fibula along the lateral aspect of the posterior tibialis muscle. The maximum transverse dimensions measure 8.5 x 9.0 cm and 13.5 cm in the craniocaudal dimension. The mass displaces the popliteal neurovascular bundle and its branches anteriorly. The signal intensity is predominantly fat signal intensity on all pulse sequences. There are thin minimally enhancing septa and/or vessels within the mass. We see no additional masses. There is nonenhancing reticulation of the subcutaneous fat of the lower leg suggestive of edema. Moderate osteoarthritis affects the knee. Slight focal nonenhancing heterogeneity of the bone marrow of the proximal tibial diaphysis may represent an island of residual red marrow.
Large calf lipoma, as described above.