E1087. Calcifications as Harbingers of Malignancy in Soft Tissue Tumors: A Case-Based Review
  1. Eric Chen; University of Washington
  2. Elizabeth Horneber; University of Washington
  3. Christine Rehwald; University of Washington
  4. Firoozeh Zadeh; University of Washington
  5. Bahar Mansoori; University of Washington
  6. Majid Chalian; University of Washington
Although benign soft tissue tumors outnumber malignant soft tissue tumors by approximately 19-fold, calcifications are disproportionately represented by malignant tumors, comprising 38% of all neoplasms with radiographically evident calcifications. Approaching calcifications based on their morphologic appearance and distribution can yield valuable clues when triaging lesions as benign versus malignant. In a fat-containing lesion, amorphous or osseous calcification can suggest dedifferentiated liposarcoma over a well-differentiated liposarcoma or lipoma. In a chondro-osseous mass, peripheral calcifications can help establish a diagnosis of myositis ossificans over extraosseous osteosarcoma. In a neurogenic tumor, amorphous calcifications can raise the possibility of a benign ancient schwannoma over a malignant peripheral nerve sheath tumor. In a juxta-articular soft-tissue mass in a young patient, stippled calcifications should prompt inclusion of synovial sarcoma in the differential. The authors present a case-based review of soft tissue calcifications using contextual factors (e.g., morphology, cell-type) that hold meaningful implications.

Educational Goals / Teaching Points
Gain familiarity with the morphology of calcifications in soft tissues. Demonstrate that approaching soft tissue calcifications based on morphologic appearance, distribution, and tumor cell-type can yield clues when triaging lesions. Present scenarios in which soft tissue calcifications are helpful in assessing the malignancy or benignity of a lesion.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
This case-based exhibit will review the morphology of soft tissue calcifications (e.g., stippled, chondroid, coarse, osseous, amorphous), with imaging correlation using multiple modalities (i.e., radiographs, CT, and MR), as demonstrated by various cases of benign and malignant pathophysiologic processes of calcification.

Approaching soft tissue calcifications according to their descriptive morphology and location can yield clues into interpreting a lesion's malignant potential. Calcifications are disproportionately represented by the most common high-grade soft tissue neoplasms, including synovial sarcoma, liposarcoma, and undifferentiated pleomorphic sarcoma, which comprise more than half of all soft tissue malignancies. Malignant tumors can have a characteristic morphology of calcifications, such as stippled calcifications in synovial sarcoma and central osseous calcifications in extraskeletal osteosarcoma.