Abstract | April 5, 2022

Clinical Conundrum: A Rare Case of Osteomyelitis Posing as Metastatic Disease

Presenting Author: Natalie Weiss, BA, BS, MD, MBA Student, 4th Year, Tulane University School of Medicine, New Orleans, LA

Coauthors: Nicholas Ottaiano, BS, Medical Student, 4th Year, Tulane University School of Medicine; Nicholas Klempf, BBA, Medical Student, 3rd Year, Tulane University School of Medicine; Kendra Harris, MD, MSc, Chair, Department of Radiation Oncology, Tulane Medical System

Learning Objectives

  1. Understand that chronic osteomyelitis is becoming more prevalent with increased rates of predisposing factors, including diabetes mellitus and peripheral vascular disease;
  2. Examine the use and limitations of FDG-PET imaging, and consider several potential diagnoses in patients with enhancing bone lesions seen on FDG-PET;
  3. Describe testing methods used to identify sources of bone lesions.

Introduction: Symptoms of chronic osteomyelitis are difficult to recognize, with non-specific pain being the most common finding.[1] Fluorodeoxyglucose positron emission tomography (FDG-PET) imaging has been found to have the highest diagnostic accuracy for confirming or excluding chronic osteomyelitis in a patient.[2] FDG-PET imaging is also the most commonly-used imaging modality for detection of cancer metastasis, representing more than 90% of current oncologic PET scans.[3] FDG uptake is increased in both tumor cells and sites of infection/inflammation due to increased metabolism of glucose. FDG-PET alone cannot reliably differentiate between the two.

Case Presentation: A 64-year-old male with a longstanding history of tobacco use presented to the emergency department with a one month history of a large lateral neck mass and associated discomfort. He was found to have a 1.0 x 0.9 x 0.8 cm lesion involving the piriform sinus on CT imaging. A panendoscopy and biopsy were subsequently performed, demonstrating moderately differentiated, p16-negative squamous cell carcinoma (SCC) of the left tongue base. A PET/CT revealed three FDG-PETavid bone lesions of indeterminate etiology. One lesion, at the level of L1, was concerning for a small volume of epidural expansion; the patient was therefore scheduled for palliative radiotherapy of T12-L2 to 30 Gray in 10 fractions. Biopsy of another lesion, within the pelvis, was scheduled for the same day as initiation of radiotherapy.

Final/Working Diagnosis: Bony metastasis vs. chronic osteomyelitis.

Management, Outcome, and Follow-up: Biopsy of the pelvis unexpectedly revealed chronic osteomyelitis without organisms present. No source of infection was found despite exhaustive workup. After a first cycle of cisplatin and 5-FU chemotherapy, the patient’s neck mass had almost entirely resolved. The patient completed a full course of chemoradiotherapy. Surveillance PET showed resolution of uptake in the neck and oropharynx several months later.

This patient received radiation to his osteomyelitic lesion. We posit the question: What effect does ratiotherapy have on chronic osteomyelitis? And, how can we mitigate risk to our patients?

References and Resources:

  1. Hatzenbuehler J, Pulling TJ. Diagnosis and Management of Osteomyelitis. Am Fam Physician. 2011;84(9):1027-1033.
  2. Termaat MF, Raijmakers PG, Scholten HJ, Bakker FC, Patka P, Haarman HJ. The accuracy of diagnostic imaging for the assessment of chronic osteomyelitis: a systematic review and meta-analysis. J Bone Joint Surg Am. 2005;87(11):2464-2471.
  3. Zhu A, Lee D, Shim H. Metabolic PET Imaging in Cancer Detection and Therapy Response. Semin Oncol. 2011;38(1):55-69. doi: 10.1053/j.seminoncol.2010.11.012. Published 2011 Feb. Accessed 20 Jul 2021.
  4. Kwee TC, de Klerk JMH, Nix M, Heggelman BGF, Dubois SV, Adams HJA. Benign Bone Conditions that May Be FDG-avid and Mimic Malignancy. Semin Nucl Med. 2017;47(4):322-351. doi: 10.1053/j.semnuclmed.2017.02.004. Published 2017 Jul. Accessed 20 Jul 2021.
Download Abstract
Back to Abstracts