Infectious Granulomas Infection is a common cause of granuloma formation. The most common infections resulting in granulomas are tuberculosis, fungi, and parasites. Part 1 Tuberculosis Abida K. Haque Tuberculosis is…

Bronchocentric Granulomatosis Roberto Barrios Keith M. Kerr Bronchocentric granulomatosis is characterized by destructive, necrotizing bronchocentric and bronchiolocentric inflammation. Early lesions show partial epithelial erosion and replacement of the airway wall…

Rare Mesenchymal Tumors Mesenchymal neoplasms including leiomyoma, lipoma, chondroma, and a variety of neural tumors rarely occur as primary lung neoplasms. Their histopathologic features are similar to those of the…

Pulmonary Ossification Mary Beth Beasley Philip T. Cagle Dendriform ossification consists of linear and branching deposits of metaplastic bone in the pulmonary interstitium that evolves from fibrosis, often contains bone…

Rounded Atelectasis Armando E. Fraire Kamala Murali Svetoslav Bardarov Rounded atelectasis (RA) is a focus of atelectatic subpleural lung parenchyma associated with infolding of the overlying pleura and scarring. RA…

Pulmonary Langerhans-Cell Histiocytosis Timothy C. Allen Mary L. Ostrowski Keith M. Kerr The Histiocyte Society divides the histiocytic disorders into three classes: Langerhans-cell histiocytosis (LCH) (class I), non-Langerhans-cell histiocytosis (class…

Intrapulmonary Lymph Nodes Alvaro C. Laga Timothy C. Allen Intrapulmonary lymph nodes are generally a normal finding. They are increasingly recognized with imaging techniques in heavy smokers and individuals with…

Focal Scars Alvaro C. Laga Timothy C. Allen A variety of conditions can be associated with localized areas of fibrosis within the lungs. The most frequent causes of these lesions…

Non-Langerhans-Cell Histiocytoses Non-Langerhans-cell histiocytoses include a myriad of histiocytoses, many of which have primarily cutaneous manifestations. The following have been described in the lung. Part 1 Erdheim-Chester Disease Timothy C….

Lymphangioleiomyomatosis Jaishree Jagirdar Lymphangioleiomyomatosis (LAM) is a rare interstitial lung disease that typically occurs in women of child-bearing age. It is characterized by widespread abnormal proliferation of smooth muscle in…