PURPOSE: To review the histologic and radiologic features in conjunction with the clinical diagnosis of surgically removed pulmonary necrotizing granulomas.
METHODS: We retrospectively reviewed 50 cases of necrotizing granulomas in surgical lung specimens with negative stains for microorganisms. An expert chest radiologist reviewed the radiologic data and was blinded to the histiologic and clinical diagnosis. The CT findings were classified as either consistent with an infectious or noninfectious etiology based upon the appearance of the lesions, presence of satellite nodules or “tree-in-bud” configuration and adenopathy consistent with an infectious etiology. Microbiological, clinical and radiographic data were reviewed until the date of last follow-up.
RESULTS: This review included 28 women and 22 men with a mean age of 57 (range 10-82 years). The nodules were solitary in 24 cases and multiple in 26 patients. Tissue cultures were positive in 10 cases: Mycobacterium avium-intracellulare complex (MAI) (9) and Mycobacterium tuberculosis (1). MAI was isolated from induced sputum in one additional patient and four patients had positive serology for histoplasmosis. Clinical diagnoses were established in 24 patients: granulomatous infection (15), sarcoidosis (4), rheumatoid nodule (2), limited Wegener's granulomatosis (2), and ANCA-negative necrotizing granulomatous vasculitis (1). Of the 15 patients diagnosed with an infection, 9 had characteristic CT findings of an infectious process. Two patients had only chest x-rays and could not be analyzed. Follow-up was available in 45 patients (mean 34 months; range x-y). No recurrence of nodules occurred in 43 patients. Two patients developed an additional pulmonary nodule, which remained stable and did not require intervention.
CONCLUSION: Characteristic findings on CT imaging can be helpful in establishing an infectious etiology of a pulmonary nodule and may be able to prevent surgical intervention when used with other clinical data. In addition, there is infrequent recurrence of surgically removed necrotizing granulomas.
CLINICAL IMPLICATIONS: Characteristic chest CT features appear to predict an infectious etiology of pulmonary nodules showing necrotizing granulomas. The positive and negative predictive value of these findings should be evaluated further.
DISCLOSURE: Brad Wilcox, No Financial Disclosure Information; No Product/Research Disclosure Information