Benign tumors of the lung

Pulmonary adenomyoma presenting as a right cardiophrenic angle mass

Pulmonary adenomyomas are rare adenomyomatous hamartomas. In the few cases described in the literature, these benign tumors are encapsulated by lung parenchyma. We describe a case of a 59 year-old woman with acetylcholine receptor antibody-negative myasthenia gravis and a right cardiophrenic mass initially thought to be a thymoma. Histopathology surprisingly revealed a pulmonary adenomyoma which involved the mediastinal fat at the cardiophrenic angle.

Intramural neurofibroma of the trachea treated by multiple stents

The case history is presented of a patient in whom an intramural tracheal neurofibroma developed, causing severe airway stenosis. The patient was treated with multiple stents over a period of 5 years because of progression of the disease and associated airflow limitation. Clinicians should be aware of this rare complication of neurofibromatosis.

Management of solitary pulmonary nodules

The solitary pulmonary nodule (SPN), a single intrapulmonary spherical lesion that is fairly well circumscribed, is a common clinical problem. About half of SPNs seen in clinical practice are malignant, usually bronchogenic carcinomas. Some nodules are primary tumors of other kinds or metastatic. Virtually all benign SPNs are tuberculous or fungal granulomas. The standard management of the SPN of unknown cause is prompt surgical removal unless benignity is established by prior chest roentgenograms showing that the nodule has been stable (i.e., showing no growth) for 2 years or by the presence of a "benign" pattern of calcification. Less universally accepted criteria for benignity include (1) transthoracic needle aspiration biopsy (TNAB) showing a specific benign process, and (2) patient's age under 30 to 35 years. Bronchoscopy has a low diagnostic yield, particularly for benign nodules. SPNs usually grow at constant rates, expressed as the "doubling time" (DT). A nodule with a DT between 20 and 400 days is usually malignant. Benign nodules usually have a DT greater than 400 days. The prospective determination of DT by serial chest roentgenograms (the "wait and watch" strategy) is widely criticized but has clinical utility in special circumstances, particularly if the likelihood of malignancy is low and/or the anticipated surgical mortality is high. The presence and pattern of calcification are best shown by high-resolution thin-section computed tomography (CT). Diffuse, laminated, central or "popcorn" patterns of calcification indicate benignity. An eccentric calcium deposit or a stippled pattern does not rule out malignancy. CT densitometry will often show "occult" calcification in nodules that show no direct visual evidence of calcium deposition. The characteristics of the edge of the nodule correlate with the likelihood of malignancy. Nodules with irregular or spiculated margins are almost always malignant. The probability that the nodule is malignant (pCA) is related to the age of the patient, the diameter of the nodule, the amount of tobacco smoke inhalation, the overall prevalence of malignancy in SPNs, the nature of the edge of the lesion, and the presence or absence of occult calcification. It is possible by Bayesian techniques to combine these factors to calculate a more precise and comprehensive prediction of pCA in any given nodule. The 5-year survival after nodule resection depends on the size of the nodule at the time of surgery; it may be as high as 80% with nodules that are 1 cm in diameter. Lymph node involvement is uncommon with small tumors, and many authorities question the need for CT staging in such cases.(ABSTRACT TRUNCATED AT 400 WORDS)

Oxidant gas injury to the lung: a discussion on the functional implications

Acute toxic inhalation by the oxidant gases, particularly ozone (O3), nitrogen dioxide (NO2) and oxygen (O2) at high tension, has been assumed to be no more than a chemical burn of the epithelial surface. More recently, oxidant toxic inhalation has been appreciated as a complex process involving biochemical, morphological and functional changes which are qualitatively similar although inducible by different agents. Recent advances in pulmonary pathophysiology, inhalation toxicology and particularly endothelial biology now challenge the validity of a theoretical framework which seemed almost complete just 5 years ago. Considerable attention has been paid in recent years to the biochemical events occurring at the moment of and immediately following exposure to the oxidant gases. Progress in elucidating the initial events has been rapid and promises a more complete picture in the near future. Studies of the pathophysiologic mechanisms associated with toxic inhalation by the oxidant gases have been relatively static, however. In this discussion, implications of recent findings in related fields were examined in an effort to identify new hypotheses and directions for investigation.

Subpleural pulmonary hamartoma: demonstration by computed tomography

A case of a subpleural pulmonary hamartoma demonstrated by computed tomography is presented. The literature on subpleural pulmonary lesions demonstrated by computed tomography is reviewed. Although peripheral pulmonary hamartomas have been well documented, we believe this is the first demonstration of a subpleural location by computed tomography scanning. In the appropriate clinical setting, pulmonary hamartoma should be included in the differential diagnosis of subpleural lesions identified on computed tomography scanning of the chest.

Endobronchial lipoma

An endobronchial lipoma has been studied with light, scanning, and transmission electron microscopes, and the literature has been reviewed. Endobronchial lipoma is a type of hamartoma unique only in terms of its specific adult-type fat cell and its location. Of 49 endobronchial lipomas, eight have been reported in obese persons. The neoplasm appears to propagate at its peripheral zone through continuous incorporation and fusion of globules of fat in the spindle-shaped precursor cells. Although benign pulmonary tumors make up about 3 percent and endobronchial lipomas only about 0.1 percent of all pulmonary tumors, benign endobronchial tumors may cause unnecessary morbidity and mortality if not properly managed.