Left calf ultrasound on a 64 year old male with NO history of trauma. What is your diagnosis?
This patient had initially been scanned to rule out DVT after left leg swelling and an elevated D Dimer (1013). At the time there had been no evidence of DVT but a 11 x 7.7 x 3.7cm heterogeneous mass was discovered in the medial calf and reported as a "tear of the medial gastrocnemius muscle with hematoma".
Follow up ultrasound imaging was recommended at the 2-3 month interval to document resolution of the hematoma and exclude the presence of an underlying lesion.
The patient returned for the follow up study six weeks later. The complex mass was again present with similar dimensions. At the time of the second scan the radiologist visited with the patient and discovered there was no antecedent history of trauma. He recommended an urgent MRI to exclude a neoplasm with spontaneous bleed.
The MRI was performed within two weeks and the final report confirmed the presence of a subacute hematoma. In addition, a deep lipomatous mass (loss of signal intensity on T1 fat saturation sequence; mild peripheral enhancement) was present. As a low grade liposarcoma could not be excluded, referral to an oncologic surgeon was recommended.
Liposarcoma is a malignancy of fat cells, and the most common soft tissue sarcoma in the adult population (17%). Liposarcoma usually presents as a slowly enlarging, painless mass in a middle-aged person, but some lesions grow rapidly and become ulcerated.
The development of a liposarcoma from a pre-existing benign lipoma is rare. Liposarcomas most frequently arise from the deep, well vascularized stroma rather than the sub mucosal or subcutaneous fat, and the trunk and the lower extremities are the most likely locations of tumor development.
The overall 5-year survival rate of patients with deep high-grade liposarcoma is less than 50%. Lung and hepatic metastases are common, especially in poorly differentiated liposarcomas.
Liposarcomas are slightly more prevalent in males than in females.
- Associated episode of trauma to the region containing the mass
- Painful swelling
- Decreased function (ie, range of motion)
- Enlargement of varicose veins
- Abdominal pain
- Weight loss
Liposarcoma usually appears as a well-circumscribed palpable non-tender mass as large as 10-11 cm in diameter. The mass tends to grow slowly over time. The largest reported liposarcoma was a retroperitoneal lesion weighing 275 lbs!! The fascial compartmentalization may cause liposarcomas to have unusual discoid and fusiform shapes.
On sonography a well-differentiated, peripheral liposarcoma is usually hyperechoic and may be indistinguishable from a lipoma; however, Doppler ultrasonography studies reveal that a liposarcoma is more vascular than a lipoma.
· Other tumors e.g: cutaneous neurofibroma
Source: E Medicine online:
A Schwartz, MD, MPH et al “Liposarcoma” (June 24, 2010 update)
Ali Nawaz Khan et al “Liposarcoma, Soft Tissue: Imaging” (March 12, 2008)