Enchondroma with Pathologic Fracture

Fifth finger pain with minor trauma • Xray of the Week

Figure 1. Name the lytic lesion in the fifth proximal phalanx and the complication.

Figure 2. Magnified view of the enchondroma with pathologic fracture. Note the typical ring and arc calcifications within the expansile, well-circumscribed metaphyseal lytic lesion with minor cortical thinning and endosteal scalloping.

Discussion:

Enchondromas are benign, cartilage-forming neoplasms of the medullary bone cavity. They are often discovered incidentally on routine imaging, most commonly found in metacarpal and phalanges bones of the hand.(1-4) Enchondromas are generally asymptomatic, however due to the typical location of the lesions even minor trauma may result in pathologic fractures causing pain and swelling.(2)

Recognizing radiographic features of this benign bony tumor can help in excluding more aggressive bone malignancies. On radiographic imaging enchondromas are classically recognized as well-circumscribed, metaphyseal lytic lesions with minor cortical thinning and endosteal scalloping. Occasionally calcifications can be seen on xray, particularly in the ‘ring and arc’ or ‘popcorn’ pattern characteristic of chondroid lesions. When an enchondroma presents with a pathologic fracture, cortical expansion may also be seen on imaging.(2,3) Negative radiographic findings such as the absence of periosteal reactions or soft tissue extension distinguish enchondromas from low-grade osteosarcomas.(1) A higher index of suspicion for malignancy may warrant further evaluation with MRI and histopathologic evaluation.

Enchondroma treatment is typically reserved for presence of a pathologic fracture, or if there is high risk of fracture in the future. The treatment options include surgical curettage followed by bone graft or filling with synthetic material, and follow-up xrays to detect any recurrence.(4,5)​

References:

1. Larbi A, Viala P, Omoumi P, et al. Cartilaginous tumours and calcified lesions of the hand: a pictorial review. Diagn Interv Imaging. 2013;94(4):395-409. doi:10.1016/j.diii.2013.01.012

2. Santini-Araujo E, Kalil RK, Bertoni F, Park Y-K. Tumors and Tumor-Like Lesions of Bone: Enchondroma. 2nd ed. 2020. Springer International Publishing; 2020. doi:10.1007/978-3-030-28315-5. https://www.springer.com/us/book/9781447172437#otherversion=9781447165774

3. Mcvey MJ, Kettner NW. Pathologic fracture of metacarpal enchondroma: Case study and differential diagnosis. Journal of Manipulative and Physiological Therapeutics. 2002;25(5):340-344. doi:10.1067/mmt.2002.124417

4. Douis H, Saifuddin A. The imaging of cartilaginous bone tumours. I. Benign lesions. Skeletal Radiol. 2012;41 (10): 1195-212. doi:10.1007/s00256-012-1427-0

5. Hakim DN, Pelly T, Kulendran M, Caris JA. Benign tumours of the bone: A review. J Bone Oncol. 2015;4(2):37-41. Published 2015 Mar 2. doi:10.1016/j.jbo.2015.02.001

Nirali Dave is a medical student at Medical University of Lublin in Poland, currently doing clinical rotations in New York. Before that she completed her undergraduate education at Rutgers University, and worked as a medical scribe. Nirali was first exposed to basic radiologic imaging while scribing, and was very quickly taken by the field. Her passion for radiology comes from the bridging of anatomy, health technologies, and patient care. In the future, she hopes to complete a diagnostic radiology residency and stay committed to clinical research and patient education.

UPDATE March 19, 2021: Nirali Dave is a resident in Radiology and Imaging Sciences at Indiana University School of Medicine.

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Kevin M. Rice, MD is the president of Global Radiology CME and is a radiologist with Cape Radiology Group. He has held several leadership positions including Board Member and Chief of Staff at Valley Presbyterian Hospital in Los Angeles, California. Dr. Rice has made several media appearances as part of his ongoing commitment to public education. Dr. Rice's passion for state of the art radiology and teaching includes acting as a guest lecturer at UCLA. In 2015, Dr. Rice and Natalie Rice founded Global Radiology CME to provide innovative radiology education at exciting international destinations, with the world's foremost authorities in their field. In 2016, Dr. Rice was nominated and became a semifinalist for a "Minnie" Award for the Most Effective Radiology Educator. He was once again a semifinalist for a "Minnie" for 2021's Most Effective Radiology Educator by AuntMinnie.com. He has continued to teach by mentoring medical students interested in radiology. Everyone who Dr. Rice has mentored has been accepted into top programs across the country including Harvard, UC San Diego, Northwestern, Vanderbilt, and Thomas Jefferson.

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