Lipomatous neoplasm, evaluate for interval change There is redemonstration of a large predominantly fat-containing mass within the posterior compartment of the calf which is situated between the gastrocnemius and soleus muscles with the cranial extent of the mass noted at the level of the knee joint. When compared to the prior exam, the mass appears slightly increased in size now measuring 15.9 x 8.3 x 9.6 cm in the greatest craniocaudal, AP, and transverse dimensions as compared to 13.8 x 6.6 x 8.2 cm previously. There is an additional component extending anteriorly between the tibia and fibula along the lateral aspect of the posterior tibialis muscle. The mass displaces the popliteal neurovascular bundle and its branches anteriorly. The signal intensity is again predominantly fat signal intensity on all pulse sequences although it also contains scattered areas of poorly defined nonadipose elements. There are thin minimally enhancing septa and/or vessels within the mass but again, no dominant nodular component is identified. There is nonenhancing reticulation of the subcutaneous fat of the lower leg suggestive of edema. There is a small joint effusion, mild synovitis, and moderate osteoarthritis of the knee. Slight focal nonenhancing heterogeneity of the bone marrow of the proximal tibial diaphysis may represent an island of residual red marrow as this appears unchanged from the prior exam.
Redemonstration of known adipose tumor within the popliteal fossa and calf which appears slightly increased in size from the prior exam and may represent an enlarging lipoma or atypical lipomatous tumor. Additional findings are described above.