Pulmonary vasculopathy in idiopathic spontaneous pneumothorax in young subjects.

BACKGROUND: We have encountered instances where young subjects with idiopathic spontaneous pneumothorax have been needlessly referred for investigation of pulmonary hypertension because surgical pathologists have misinterpreted the significance of medial hypertrophy and intimal fibrosis of muscular pulmonary arteries in lung resection specimens. METHODS: We reviewed 20 cases of idiopathic spontaneous pneumothorax and determined the prevalence and severity of medial and intimal lesions in the pulmonary arteries and pulmonary veins. We correlated the vascular changes with inflammation and fibrosis in the lung. RESULTS: Pulmonary artery medial hypertrophy was seen in 15% of cases, pulmonary artery intimal fibrosis in 90% of cases, and pulmonary vein intimal fibrosis in 80% of cases. In 95% of cases, the lung showed some fibrosis and chronic inflammation. There was a significant positive correlation between pulmonary artery medial thickness and lung fibrosis and inflammation scores. CONCLUSIONS: Pulmonary artery medial hypertrophy and intimal fibrosis of pulmonary arteries and pulmonary veins are commonly seen in resected lung tissue from patients with idiopathic spontaneous pneumothorax. The vascular lesions are probably secondary to chronic inflammation and fibrosis in the adjacent lung. They are not clinically significant and do not represent hypertensive pulmonary vascular disease.

Enhanced cancer metastasis after monocrotaline-induced lung injury.

The lung is a target in several models of environmentally induced injury and is also a common site for the growth of metastases from circulating cancer cells. In these experiments, we have tested the hypothesis that pulmonary damage can facilitate the metastasis of cancer to the lung. We have studied the effect of monocrotaline-induced lung injury on the retention and metastasis of intravenously injected Walker carcinosarcoma 256 cells in the lung and the effect of this injury on spontaneous metastasis in animals with intramuscular tumor transplants. Female Wistar rats were given a single subcutaneous injection of monocrotaline (60 mg/kg). The degree of lung injury after monocrotaline was assessed by bronchoalveolar lavage, by histological and ultrastructural examination, and by measurement of right ventricular hypertrophy. To assess the effects of monocrotaline on metastasis, animals were injected iv with 2 X 10(7) [125I]iododeoxyuridine-labeled or unlabeled Walker 256 carcinosarcoma cells at various periods of time (1 day to 20 days) after monocrotaline. The retention of labeled cells was determined by gamma counts of lungs 24 hr after injection. There was a direct correlation between the severity of lung injury and the number of cancer cells retained in the lung 24 hr after injection. Metastasis was quantified by morphometric analysis of histologic sections prepared from lungs 1 week after an injection of unlabeled cells. The median area of lung involved by tumor after iv injection was 39% for rats injected with cancer cells 10 days after monocrotaline vs 3% for controls. In studies on spontaneous metastasis, rats were given an intramuscular injection of Walker 256 cells 5 days after monocrotaline and metastasis was quantified by morphometry 7 days after tumor transplantation. The median tumor burden of animals pretreated with monocrotaline was 37% vs 8% for controls. We conclude that lung injury initiated by monocrotaline can facilitate the spread of the rat Walker 256 carcinosarcoma.

Bone core biopsies. Plastic or paraffin?

Plastic embedding of bone core biopsy specimens has been promoted as providing superior morphology, primarily because semi-thin sections can thereby be cut at 1-2 mu. The major disadvantages of plastic embedding are that it increases the technical load, is more expensive, and potentially has its own intrinsic problems, including difficulties in performing special stains and immunoperoxidase studies. In order to investigate the possibility that semi-thin paraffin sections may provide similar morphological results without the intrinsic disadvantages of plastic sections, we examined 45 bone core biopsy specimens that were sufficiently large to process one half in plastic and the other half in paraffin following decalcification. Both were cut at 1-2 mu. Although many plastic sections appear esthetically more pleasing, semi-thin paraffin sections of very high quality can also be obtained routinely. Additional advantages of paraffin sections were the ability to perform peroxidase studies, lower cost, less technologist time, and avoidance of problems occasionally arising with plastic, such as difficulties with impregnation or problems with polymerization. Peroxidase studies were particularly useful in patients with possible myeloma that was not overt on hematoxylin-and-eosin section and in confirming the presence or source of metastatic carcinoma. We therefore recommend the use of semi-thin (1-2 mu) paraffin sections for routine examination of bone core biopsy specimens.

Adenomyoma of the common bile duct.

We report an unusual case of biliary obstruction secondary to adenomyoma of the common bile duct. Adenomyomas are benign tumors, found infrequently in the biliary tree. Clinical presentation, biochemical, radiographic, and endoscopic investigations do not distinguish adenomyomas from malignant or other lesions; diagnosis requires histological examination. The natural history and optimal treatment of these tumors have not been established.