most patients were above 55 years old and had either a diagnosis of diffuse large B cell lymphoma or chronic lymphocytic leukemia. The majority of patients presented with progressive dyspnea, cough, fevers and hypoxemia after at least 4 cycles of rituximab. Chest radiographs and computed tomographies often showed diffuse bilateral interstitial infiltrates. Lung biopsies predominantly revealed alveolar damage and interstitial fibrosis. Although spontaneous resolution occurred with discontinuation of rituximab, more than half of the patients required high-dose corticosteroids. The duration of steroid therapy was usually 1–2 months

 

Subacute hypersensitivity pnuemonitis에 해당하는 전형적인 GGO/centrolobular nodules of lower lobe

 

Acute: lower lobe에 주로  sparing of  the apex. Nodular/GGO pattern

Chronic: upper lobe에 주로, Volume loss

subcutaneous emphysema 발생하기도

 

Allergic lung disease resulted from inhalation of antigenic organic dusts.
Farmer's lung: representative of hypersensitivity pneumonitis, induced from inhalation of fungal organism.

1. Acute stage: diffuse poorly-defined air-space consolidation / ground-glass attenuation.
Pathologically, alveolar filling of polymorphonuclear cells, eosinophils, and lymphocytes.
2. Subacute stage: fine nodular pattern showing peribronchial distribution.

3. Chronic stage: patchy fibrosis.

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 1. In the acute stage the chest radiography is occasionally normal.
2. The most common radiographic finding in the acute or subacute stage is small pulmonary nodules, usually 1 to 3 mm. They are almost always bilateral. In the subacute phase the majority of patients have diffuse ground glass opacity and small nodulation on HRCT.
3. The characteristic radiologic changes in the chronic stage are of a scarring process with loss of lung volume, which has a marked (85%) upper lobe predominance. Chronic HRCT changes consist of coarse, irregular, linear opacities with parenchymal distortion