Necrobiotic pulmonary nodules are sterile cavitating lung nodules associated with rheumatoid arthritis and inflammatory bowel disease (more often with ulcerative colitis than Crohn disease).
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Epidemiology
They are more common in men 5.
Associations
Clinical presentation
Usually asymptomatic, symptoms tend to occur when nodules cavitate or rupture into the pleural cavity creating a bronchopleural.
Pathology
Histologically, necrobiotic nodules consist of a core of fibrinoid necrosis and sterile aggregate of numerous epithelioid histiocytes arranged in indistinct nodules with an infiltrate of lymphocytes, plasma cells, and multinucleated giant cells. Features are those of a granuloma 5.
Methotrexate has been implicated to an increase incidence of necrobiotic nodules due to activation of adenosine A1 receptors and consequent cellular fusion into multinucleated giant cells 5.
Radiographic features
can be single or multiple nodules
predominance in a subpleural distribution
often cavitate
Treatment and prognosis
Although typically regress with treatment of the background disease, they may regress spontaneously. Treatment of rheumatoid arthritis with methotrexate can lead to a paradoxical enlargement of the nodules 5.
Complications
When a rupture of a necrobiotic nodule occurs, complications might include 5:
pleural effusion
superimposed infection
bronchopleural fistula
Differential diagnosis
atypical pulmonary infection
See also
CAVITY (mnemonic for cavitating lung mass)