Other Primary Lung Tumors in Children



Other Primary Lung Tumors in Children


Megan K. Dishop



Mass lesions of the lung in children are most commonly developmental malformations or cystic lesions, with a ratio of 10 non-neoplastic lesions for every neoplasm. Metastatic tumors are at least 5 times more common than primary lung tumors. In addition to pleuropulmonary blastoma (see Chapter 152), a wide variety of primary benign and malignant lung tumors may rarely present as endobronchial or parenchymal masses in the pediatric age group.


Myofibroblastic Tumors

Inflammatory myofibroblastic tumor, also called “inflammatory pseudotumor” or “plasma cell granuloma,” is the most common primary tumor of the lungs in children. It may occur within the parenchyma or as an obstructive endobronchial lesion. As in adults, these tumors are composed of spindled cells admixed with scattered inflammatory cells, including lymphocytes, plasma cells, and rare eosinophils. Hypocellular zones may be seen.

Congenital peribronchial myofibroblastic tumor, also described in the early literature as “congenital bronchopulmonary fibrosarcoma” and “congenital leiomyosarcoma,” is a rare myofibroblastic tumor of neonates formed by intersecting broad bands of bland spindled cells, vaguely subdividing the lung parenchyma along the connective tissue planes of the pleura, interlobular septa, and peribronchial regions. Malformed cartilage plates are interspersed with the spindle-cell proliferation in the peribronchial regions.

Myofibromatosis refers to multifocal myofibroblastic lesions, typically diagnosed in infants and young children. In addition to skin and soft-tissue distribution, visceral involvement may occur. Multiple lesions in the lung may mimic metastatic tumor.


Histologic Features



  • Inflammatory myofibroblastic tumor—Nodular proliferation of haphazardly arranged spindled cells, admixed with inflammatory cells. Areas of hyalinization and variable cellularity may be seen. The spindled cells are at least focally positive for smooth-muscle actin, and may be express ALK1 protein.


  • Congenital peribronchial myofibroblastic tumor—Broad bands of bland spindled cells coursing along peribronchial connective tissue and interlobular septa, partially subdividing entrapped lung parenchyma.


  • Myofibromatosis—Multifocal areas of bland spindled cells with myofibroblast differentiation. Hemangiopericytomatous vasculature and intravascular protrusion of spindled cells may be identified.


Neuroendocrine Carcinoma (Carcinoid Tumor)

The tracheobronchial tree is the most common site of extra-appendiceal carcinoid tumors in children. Bronchial carcinoid tumors are considered to be low-grade neuroendocrine tumors, and although most behave in a benign fashion, recurrence or metastasis may occur.

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Jul 14, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Other Primary Lung Tumors in Children

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