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Bronchoscopic Image

Pulmonary Blastoma

Oba, Yuji MD*; Salzman, Gary A MD*; Miranda, Roberto N MD

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doi: 10.1097/01.lab.0000130635.18770.4b
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A 38-year-old black man was referred for evaluation of a chest radiographic abnormality and shortness of breath increasing over the past 8 weeks. He had had a productive yellow cough but no hemoptysis. He had to quit his job as a concrete worker secondary to his shortness of breath. He had a 10-lb. weight loss in the last couple of months. His medical history was unremarkable except for a 10-year history of tobacco use and recreational use of marijuana.

Physical examination revealed a well-developed, well-nourished man in no apparent distress. His lungs were clear with the exception of the left lower lobe, which revealed crackles. The rest of the physical examination was unremarkable. CBC count revealed anemia (hemoglobin 9.6 g/dL and hematocrit 30%). Electrolytes and liver function panel were normal.

The chest radiograph revealed marked airspace infiltrates within the left lower lobe with suggestion of a parenchymal mass. Chest computed tomography scan revealed a large left upper lobe cavitating mass, which extended inferiorly to encase and completely obstruct the left lower lobe and lingular bronchi. The mediastinal lymph nodes were not involved. A bronchoscopy revealed an endobronchial mass completely obstructing the left lower lobe bronchus (Fig. 1). A transbronchial biopsy was performed but it was nondiagnostic. The patient underwent thoracotomy to establish a diagnosis.

FIGURE 1.
FIGURE 1.:
Photograph demonstrating an endobronchial mass completely obstructing the left lower lobe bronchus.

Histology showed a biphasic pulmonary blastoma. The tumor measured 8 × 4.5 × 5 cm and was well-circumscribed, soft in consistency, and tan–brown in color with focal areas of cystic degeneration. Approximately 30% of the tumor was necrosed. The tumor was composed of endometrioid-like glands arranged in nests and cords, surrounded by an embryonic blastomatous stroma (Fig. 2). Mediastinal lymph nodes and surgical margins were free of malignancy. The patient underwent left lower lobectomy without complications.

FIGURE 2.
FIGURE 2.:
Biphasic tumor composed of endometrioid-like glands surrounded by blastomatous stroma.

Pulmonary blastoma is a rare lung neoplasm and accounts for 0.25% to 0.5% of all primary lung neoplasms.1 Microscopically, it resembles developing fetal lung and is composed of epithelial and mesenchymal elements. It should not be confused with pleuropulmonary blastoma of childhood, which is believed to develop from immature pulmonary “blastema.”2,3 A number of observations suggest that pulmonary blastoma derives from endodermal tissue or pluripotential stem cells rather than pulmonary blastema.

Some groups report a male predominance (2.5:1); however, in a recent large series, the sex incidence was approximately equal.4 Tumors are seen mainly in adults with an average age at diagnosis of 35 to 40 years. Approximately 80% of patients are smokers. Many patients present with cough, hemoptysis, and chest pain, but up to 40% of patients can be asymptomatic.4

The most common radiologic manifestation of pulmonary blastoma is a solitary, well-defined peripheral nodule or mass that favors the upper lobes. Calcification and cavitation are rare. In 1 study, endobronchial growth was observed in 38% of cases.4 Bronchoscopy is often nondiagnostic, and a correct or suggestive diagnosis can be achieved in only one third of cases.5 They are highly aggressive and associated with poor prognosis. Death usually occurs within 1 to 2 years.6 The primary treatment is surgery; however, radiotherapy and chemotherapy have also been used.

The patient received several courses of postoperative chemotherapy, including etoposide and cisplatin; however, his tumor relapsed in the lung and metastasized to the liver and the kidneys 1 year after surgery and he died.

REFERENCES

1. Koss MN. Pulmonary blastomas. Cancer Treat Res. 1995;72:349–362.
2. Manivel JC, Priest JR, Watterson J, et al. Pleuropulmonary blastoma. The so-called pulmonary blastoma of childhood. Cancer. 1988;62:1516–1526.
3. Dehner LP. Pleuropulmonary blastoma is the pulmonary blastoma of childhood. Semin Diagn Pathol. 1994;11:144–151.
4. Koss MN, Hochholzer L, O’Leary T. Pulmonary blastomas. Cancer. 1991;67:2368–2381.
5. Francis D, Jacobsen M. Pulmonary blastoma. Curr Top Pathol. 1983;73:265–294.
6. Larsen H, Sorensen JB. Pulmonary blastoma: a review with special emphasis on prognosis and treatment. Cancer Treat Rev. 1996;22:145–160.
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