E2067. MR Imaging Features and Pitfalls of Typical and Atypical Benign Musculoskeletal Soft Tissue Tumors: A Case-Based Review
  1. Ergent Zhiva; University of Cincinnati
  2. Casey Reed; University of Cincinnati
  3. Artemis Petrides; University of Cincinnati
Musculoskeletal (MSK) soft tissue tumors are routinely encountered and imaged in clinical practice and most are benign with a benign to malignant ratio reported up to 100:1 in a hospital population study (1). While typical MSK benign soft tissue tumors are often diagnosed based on their expected imaging features, this is not always the case. Additionally, uncommon or atypical benign soft tissue tumors can confound differentiation from malignancy or infection, potentially resulting in misdiagnosis, unnecessary invasive procedures, and undue patient anxiety. Indeterminate tumors will invariably undergo biopsy as a necessary next step adding to the importance of a reasonably honed-in differential diagnosis. The referring clinician or surgeon also expects the radiologist to report on pertinent adjacent peri-tumoral anatomy, such relationship to adjacent neurovasculature that will determine biopsy approach and treatment planning if necessary.

Educational Goals / Teaching Points
The goals and objectives of the educational exhibit will be to review and familiarize audience with differentiating MR imaging features and potential pitfalls of typical, atypical, and diagnostically challenging benign MSK soft tissue masses from a pathologically proven collection of cases. Emphasize relevant imaging information that the surgeon needs to know. Provide MRI-sonographic correlation of various tumors when available. Review the World Health Organization (WHO) classification of soft tissue tumors with emphasis on benign entities.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Mesenchymal origin and subtypes of benign soft tissue tumors. Uncommon benign soft tissue tumors and what imaging and clinical features to look for. Atypical location of typical soft tissue tumors on MRI. Atypical MRI appearance of common soft tissue tumors. When and how is ultrasound evaluation of soft tissue tumors beneficial and when is it redundant.

The prevalence of benign soft tissue tumors raises the importance of radiologists to be familiar with their imaging features in order to formulate an appropriate differential diagnosis, reasonably differentiate from malignant tumors when possible, and aid in potential percutaneous or excisional biopsy planning.