E1862. Don't Touch Me! Distinguishing Normal Anatomic Variants, Benign Lesions, Non-Tumor Pathology, and Artifact From Malignant Osseous Lesions
  1. Shruthi Suresh; Geisinger Medical Center
  2. James Kachmar; Geisinger Medical Center
  3. Anthony Zaklama; Geisinger Medical Center
Unnecessary follow-up advanced imaging and biopsy of abnormal appearing osseous lesions can not only cause physical and mental injury to a patient but also drive up healthcare costs, place unnecessary strain in setting with limited healthcare resources and sometimes lead to litigation. The purpose of this imaging review is to equip residents, musculoskeletal fellows and general radiologists with tools to differentiate between malignant lesions and their “do not touch” doppelgangers.

Educational Goals / Teaching Points
Understand the consequences of misdiagnosing a "do not touch lesion". Know the location of normal anatomic variants that can mislead you to diagnosing a lytic lesion. Know how to distinguish a benign sclerotic lesion from a malignant one. Distinguish enthesopathy from an aggressive malignant lesion. Distinguish the appearance of subacute traumatic injury from malignancy. Know the "Aunt Minnie" appearance of tumefactive metabolic mimicry. Distinguish between the atypical appearance of arthropathy and osseous tumor. Distinguish between the normal post-operative/procedural/treatment appearance of bone and malignancy. Distinguish between imaging artifact and true osseous malignancy.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Understand that red marrow re-conversion demonstrates signal drop on out of phase imaging and is never hypointense to skeletal muscle on short TR sequences. Identify the normally lucent appearing anatomic landmarks in the humerus, hip and calcaneus. Identify normal anatomic variants of the skull, axial and appendicular skeleton that may appear “atypical”. Distinguish myositis ossificans, subperiosteal hematoma and stress fractures from true malignancy. Understand the tumefactive imaging appearance of hyperparathyroidism, melorheostosis, osteonecrosis and Paget’s disease. Understand the post-procedural/treatment imaging appearance of bone marrow biopsy, biceps tenodesis, particle disease and radiation related changes. Understand common artifacts that mimic lytic lesions and which repeat views to order.

An understanding of common mimics of bone tumor can help avoid unnecessary and expensive imaging follow-up or worse still an unnecessary biopsy.