ARRS 2022 Abstracts

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2077. Imaging of Dermatofibrosarcoma Protuberans with Pathologic Correlation
Authors * Denotes Presenting Author
  1. Mark Murphey *; AIRP
  2. James Jelinek; Medstar Washington Hospital Center
  3. Mark Kransdorf; Mayo Clinic
  4. Stephen Savioli; AIRP
Objective:
This study aims to evaluate the imaging appearance of dermatofibrosarcoma protuberans (DFSP) with pathologic correlation. Specific attention was directed to identification of sparing of the epidermis by imaging.

Materials and Methods:
We retrospectively reviewed 36 patients with pathologically confirmed DFSP. Radiologic studies were reviewed by two musculoskeletal radiologists with agreement by consensus. Imaging included radiography ( n=11), ultrasound (US) (n=5), computed tomography (CT) (n=14) and magnetic resonance imaging (MRI) (n=24). Evaluation included patient demographics, lesion location and size, and intrinsic features.

Results:
Patient age ranged from 8 months to 82 years (average = 38 years) with 64% male and 36% female. The trunk was most frequently involved in 48% of cases, followed by the upper extremity (25%), lower extremity (19%) and the head/neck (8%). All lesions were centered in the subcutaneous tissues. Protuberance of the skin surface was seen in 90% of cases. Lesion size ranged from 3 - 20 cm in maximal dimension (average = 4-7cm). On radiographs, lesions were nonspecific soft tissue masses (82%) without calcification. US predominantly demonstrated a relatively heterogeneous hypoechoic (80%) mass with hypervascularity on Doppler (100%) examination. CT revealed a mildly heterogeneous (64%) mass with similar attenuation to muscle (64%). On MRI, the predominant T1 and T2 signal intensity was low/intermediate (96%) and low/intermediate (54%), respectively, with mild heterogeneity. Marked diffuse heterogeneous enhancement was seen in 82% cases evaluated with contrast on MRI. Satellite nodules were seen in 11% of cases. Areas of sparing of the epidermis were seen in 75% of cases in nonulcerated regions. This finding corresponded to pathologic features with lack of epidermal involvement (grenz zone). Subcutaneous extension was seen in 37% of cases at cross-sectional imaging.

Conclusion:
Imaging features of DFSP are those of a subcutaneous protuberant soft tissue mass with nonspecific intrinsic characteristics. Suggestive features of this diagnosis include satellite nodules and sparing of the epidermis in nonulcerated regions. This latter finding may aid in distinction from skin appendage tumors such as melanoma and squamous cell carcinoma and corresponds to the pathologic grenz zone.