Blastoma

Pulmonary blastoma, a rare primary lung neoplasm occurring in both children and adults, is histologically distinct from other lung tumors. A patient is described who presented with massive and persistent hemothorax. Based on experience, it is possible that in advanced cases of this tumor, more vigorous chemotherapy is needed against both histologic elements.

Pulmonary blastoma is a very rare malignant primary lung neoplasm; 74 cases have been reported to date. It was first described as a histologic entity by Barrett and Barnard in 1944[1] and again reported by Barnard in 1952.[2] Later Spencer[3] suggested the term pulmonary blastoma because of his concept of the tumor arising from the pulmonary blastema in a manner analogous to the origin of Wilm's tumor from the renal blastema. This concept has been questioned recently on the basis of electron microscopic studies;[4,5] the origin is now uncertain.[6]

The presenting symptoms are usually coughing, chest pain, and occasionally hemoptysis. Our patient presented with massive hemothorax which, to our knowledge, has not been reported before.

The treatment of the tumor has most commonly been by surgery alone, although both radiation and chemotherapy have been given as adjuvants or to treat metastatic disease.

CASE REPORT

A 39-year-old man was transferred to our institution five days after his emergency admission to another hospital because of severe dyspnea, chest pain, and fever. He had no history of lung diseases or any other serious illness. He was transferred to us because of fast reaccumulation of hemorragic right pleural effusion, following two thoracenteses with 700 ml and 600 ml of hemorrhagic fluid aspirated in a five-day interval.

At our institution, a right chest tube was inserted and 800 ml of hemorrhagic fluid was removed. Repeated cytologic examination disclosed no malignant cells. Bronchoscopy with a flexible bronchoscope disclosed no endobronchial tumor. The computed tomographic (CT) scan of his chest showed a huge tumor in his right lung extending to the mediastinum (Fig 1). Results of the remainder of the workup were not diagnostic. Due to the persistent hemothorax, the right side of his chest was explored surgically. The tumor had a dark-red and yellowish appearance with many areas of necrosis. The pathologic findings of the tumor showed a biphasic structure with a major undifferentiated mesenchymal and a minor epithelial component. The epithelial elements consisted of primitive tumor cells among which tubular structures had developed. They were embedded in a sarcomatous type of mesenchymal stroma consisting of undifferentiated connective tissue cells with foci of cartilaginous tissue (Fig 2).

Following his recovery from the operation, he was treated with CYVADIC (cyclophosphamide [Cytoxan]: 800 mg IV; vincristine [Oncovin]: 2 mg IV; doxorubicin [Adriamycin]: 80 mg IV; and dacarbazine [DTIC]: 400 mg IV days 1 to 3) combination chemotherapy. He had an impressive subjective response to this combination. Very soon he gained weight, he had no chest pain or fever, and no reaccumulation of the pleural effusion was observed. The patient could be treated at the outpatient clinic for four more monthly courses of chemotherapy. However, the chest roentgenograms did not show any real reduction in the size of the lung tumor. Five months after the initiation of his treatment, he showed signs of fast deterioration. He started losing weight and complained of chest pain and dyspnea. No other treatment was given to him except the supportive measurements. He died a month later with no evidence of distant metastases.

DISCUSSION

Spencer[1] was the first to suggest the term pulmonary blastoma for this very rare lung tumor because of his concept of the tumor arising from the pulmonary blastoma in a productive cough, chest pain, and rarely hemoptysis, not massive and persistent hemothorax as in our patient. The tumor is usually located in the peripheral portion of the lung, although in one child at least, the lesion arose centrally and it was endobronchial in origin.[5]

The treatment of this tumor has been most commonly by surgery alone, although both irradiation and chemotherapy have been given both as adjuvants or to treat metastatic disease. The prognosis is poor among those patients who have metastases or a primary tumor more than 5 cm in diameter.[3] There have been patients with prolonged survival after a noncurative surgery followed by combination chemotherapy with drugs like cyclophosphamide, vincristine, doxorubicin, and dactinomycin.[2,4,6] The selection of the above combination of chemotherapy was based on putative histogenic similarities of pulmonary blastoma to Wilms' tumor and embryonal rhabdomyosarcoma. Our selection of chemotherapy was based mainly on the domination of the sarcomatous over the epithelial elements in the histology report. We noticed a distinct subjective response of short duration, which did not correspond to definitive objective response.

REFERENCES

[1] Spencer H. Pulmonary blastomas. J Pathol Bacteriol 1961; 82:161-65

[2] McCann MP, Fu Y, Kay S. Pulmonary blastoma: a light and electron microscopic study. Cancer 1976; 38:789-97

[3] Fung CH, Lo JW, Yonan TN, Milloy FJ, Hakami MM, Changus GW. Pulmonary blastoma: an ultrastructural study with a brief review of literature and a discussion of pathogenesis. Cancer 1977; 39:153-63

[4] Medbery CA, Bibro MC, Phares JC, Veach SR, Martin JE, Pasquale DN. Pulmonary blastoma: case report and literature review of chemotherapy experience. Cancer 1984; 53:2413-16

[5] Leeson TS, Leeson CR. A light and electron microscope study of developing respiratory tissue in the rat. J Anat 1964; 98:183-93

[6] Roth JA, Elguezabal A. Pulmonary blastoma evolving into carcinosarcoma. Am J Surg Pathol 1978; 2:407-13

COPYRIGHT 1992 American College of Chest Physicians
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