IS Case 534: Right middle lobe necrotizing lung granuloma

Keith Forrest Dockery, MD, MS

University of Rochester

Imaging Sciences URMC 2010
Publication Date: 2010-09-11

History

Patient is a 48-year-old female smoker who presented for work-up of a right lung mass found during evaluation of persistent anterior chest discomfort. The patient was treated initially for gastroesophageal reflux disease (GERD), then with antibiotics, both with limited benefit. She underwent outside chest radiographs and computed tomography, prior to referral. She is now planned for wedge-resection.

Findings

See figures

Diagnosis

Right middle lobe necrotizing lung granuloma

Discussion

This patient presented for work-up of a right lung mass on chest radiograph in the setting of a smoking history. Positron emission tomography-computed tomography (PET-CT) is a standard modality for evaluation of a solitary pulmonary nodule in this setting. F-18 Fluorodeoxy glucose (FDG)-PET standard uptake values (SUV) less than 2 favor a benign etiology, assuming CT imaging characteristics and history are concordant. Higher SUV ranges are more indicative of malignancy, though numerous false positives have been identified in the literature, including granulomatous disease and infection.

In this patient, there is low-grade, non-specific metabolic activity in a lobulated, soft-tissue attenuation mass in the right middle lobe. CT characteristics are not specific. Taken together, the lobulated appearance and low-grade activity favor a benign etiology. Wedge resection of the mass revealed a necrotizing granuloma of uncertain etiology. The inciting infection/etiology in necrotizing granulomas is frequently not found, even after surgical excision.

References

  1. Thiessen R, Seely JM, Matzinger FR, et al. Necrotizing granuloma of the lung: imaging characteristics and imaging-guided diagnosis. AJR Am J Roentgenol. 2007 Dec;189(6):1397-401. 18029876
  2. Takalkar AM, El-Haddad G, Lilien DL. FDG-PET and PET/CT - Part II. Indian J Radiol Imaging [serial online] 2008; 18(1):17-36. Available from: http://www.ijri.org/text.asp?2008/18/1/17/38504.

2 images