E1298. Atypical Clinical Manifestations of Gout in Extremities Which May Lead to Misdiagnosis on Imaging: Radiologists Beware!
  1. Beiyi Shen; Stony Brook Medicine
  2. Musa Mufti; Stony Brook Medicine
  3. Jessa Tunacao; Mather Hospital; Stony Brook Medicine
  4. Kathleen Finzel; Stony Brook Medicine
  5. Kevin Baker; Stony Brook Medicine
  6. Elaine Gould; Stony Brook Medicine
  7. Daichi Hayashi; Stony Brook Medicine
Deposition of tophus is a commonly found pathologic feature of chronic gout. However, if gouty tophus develops in an atypical location, imaging findings alone may not make radiologists immediately think of gout. Due to osseous destructive changes adjacent to the gouty tophus, differential diagnoses based on imaging alone include other aggressive processes such as osteomyelitis or even malignancy. For example, gouty tophus in the knee may give locking sensation, mimicking meniscal tears or intra-articular bodies, or tophus deposition of flexor tendon of the wrist may cause carpal tunnel syndrome [1,2]. The aim of this exhibit is to show examples of atypical manifestation of gout in extremities with multimodality imaging to make the viewers aware of such presentation in often unsuspected clinical scenario.

Educational Goals / Teaching Points
1. To review epidemiological and clinical features of gouty arthropathy 2. To describe and illustrate radiographic, CT, Ultrasound and MRI characteristics of gouty arthropathy including tophi deposition 3. To highlight the need for awareness of radiologists that gouty tophus may present in atypical fashion and potentially misdiagnosed as other aggressive pathology such as osteomyelitis and importance of review clinical history before interpreting images

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
1. Overview of gouty arthropathy: Incidence, clinical presentation, and typical locations 2. Pictorial review of X-ray, CT, Ultrasound and MRI characteristics of gouty arthropathy including tophi deposition in atypical locations, leading to atypical/uncommon way of clinical presentation 3. Pictorial review of potential differential diagnoses such as other crystal deposition diseases (calcium pyrophosphate dihydrate disease, hydroxyapatite deposition disease), osteomyelitis, tendon/ligamentous pathology, and malignant process 4. Take home messages

Gout does not always present with typical signs and symptoms such as severe joint pain from inflammatory arthritis, and atypical presentations of gouty tophi could mislead the diagnosis into incorrect diagnostic pathway, such as osteomyelitis, mechanical tendon tear, or soft tissue neoplasm. Delayed correct diagnosis and appropriate treatment could lead to severe impairment. Radiologists need to be aware of atypical way of gouty tophi presentation in extremities and be always cognizant of correlating imaging findings with all clinical information available, including recent lab values in case of the presence of hyperuricemia in a patient with yet undiagnosed gout.