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September 9, 1974

Large (>4 cm) Solitary Pulmonary Mass

Author Affiliations

From the Department of Radiology, Walter Reed Army Medical Center (COL Reeder) and the Pulmonary and Mediastinal Pathology Branch, Armed Forces Institute of Pathology (Dr. Hochholzer), Washington, DC.

JAMA. 1974;229(11):1493-1494. doi:10.1001/jama.1974.03230490073037


  1. Abscess

  2. Metastasis (eg, from sarcoma or Wilms tumor)


  1. Arteriovenous malformation

  2. Cyst, fluid-filled (bronchogenic, hydatid)

  3. Granuloma (tuberculosis or fungus disease, especially cryptococcosis)

  4. Hematoma

  5. Inflammatory pseudotumor: organized pneumonia (types: fibroxanthoma, fibroma, plasma cell granuloma, sclerosing hemangioma)

  6. [Loculated interlobar or pleural fluid]

  7. Lymphoma

  8. [Mediastinal mass]

  9. Pulmonary sequestration

  10. Sarcoma or blastoma (embryoma) of lung.

(Entities in brackets can be confused roentgenographically with pulmonary masses.)

Diagnosis  Inflammatory pseudotumor of lung.1

Comment  After an uneventful medical workup, thoracotomy was performed with excision of a firm 6-cm mass from the right lower lobe. The mass was discrete and separate from the adjacent compressed lung parenchyma but not truly encapsulated. The histologic pattern was pleomorphic, with an admixture of fibroblasts, collagen fibers, histiocytes, plasma cells, lymphocytes, eosinophils and foamy macrophages.In discussing the differential diagnosis of a large, solitary, pulmonary mass in an asymptomatic child, only a few