SSR Example Formatted Abstract

IMAGING APPEARANCE OF CONGENITAL FIBROSARCOMA OF THE SOFT TISSUES

Jennings BT, Armed Forces Institute of Pathology, Washington, DC, USA, Murphey MD, Arcara LK, Fanburg-Smith JC.

Purpose: To describe the radiologic appearance of congenital (infantile) fibrosarcoma of the soft tissues, with an emphasis on cross-sectional imaging.

Materials and Methods: Three musculoskeletal radiologists retrospectively reviewed 13 cases of pathologically proven congenital fibrosarcoma. Radiologic studies reviewed by consensus included: radiographs (n=10), bone scintigraphy (n=6), ultrasound (US) (n=7), CT (n=5), and MRI (n=8). Evaluation included patient demographics; lesion size, mineralization and location; lesion vascularity; and intrinsic characteristics on US, CT, and MRI.

Results: Congenital fibrosarcoma patients included six males and seven females ranging in age from 25 weeks gestation to 48 months (average, 7 months; median, 2 months). Ten of 13 patients (77%) were less than 10 months of age. All patients presented with a soft tissue mass. The average lesion size was 7.4 centimeters (cm) x 5.6 cm. Five cases had bone erosion (n= 4) and/or invasion (n= 3). Tumor involved the upper extremity (46%), lower extremity (46%) and occipital soft tissues (8%). Nine cases (82%) were centered in muscle on CT or MRI. Moderate to marked radionuclide uptake was seen on blood flow/pool images in 2 of 3 cases. Delayed radionuclide uptake was mild (n=3) or not present (n=2). Infiltrative tumor margins were seen by ultrasound in five cases (71%), by CT in all cases (n=5), and by MRI in five cases (63%). Tumor heterogeneity was prominent on US (100%), CT (80%), and MRI (T1 [75%], T2 [100%]). Enhancement was heterogeneous in all cases by CT (n=2) and MRI (n=2). Internal tumor vessels were identified by Doppler US in four cases (100%) and by MRI in three cases (38%). Hemorrhage was seen by CT in 40% of cases (n=2) and by MRI in 50% of cases (n=4).

Conclusion: Consistent cross-sectional imaging features of congenital fibrosarcoma were the presence of a large, heterogeneous, infiltrative soft tissue mass in an extremity of an infant with enhancement and identifiable internal vessels.