An analysis of 155 solitary lung lesions illustrating the differential diagnosis of mixed tumours of the lung

Comparative analysis of three-dimensional and two-dimensional models for predicting the malignancy probability of subsolid nodules

AIM

To construct three-dimensional (3D) and two-dimensional (2D) models to predict the malignancy probability of subsolid nodules (SSNs) and compare their effectiveness.

MATERIALS AND METHODS

A total of 371 SSNs from 332 patients, collected between January 2020 and January 2024, were included in the study. The SSNs were divided into a training set for constructing the models and a test set for validating the models. Models were developed using binary logistic backward regression, based on factors that showed significant differences in univariate analyses. The performance of the models was assessed using the area under the curve (AUC) of the receiver operating characteristic (ROC). The AUCs of different models were compared using the DeLong test.

RESULTS

The AUCs for the two 3D models, one 2D model, and the Brock model were 0.785 (0.733-0.836), 0.776 (0.723-0.829), 0.764 (0.710-0.818), and 0.738 (0.679-0.798) in the training set. In the test set, these AUCs were 0.817 (0.706-0.928), 0.796 (0.679-0.913), 0.771 (0.647-0.895), and 0.790 (0.678-0.903). The two 3D models demonstrated statistically significant differences from the Brock model in the training set (P=0.024 and P=0.046). None of the four models showed significant differences in the test set (all P>0.05).

CONCLUSION

The 3D models outperform both the 2D model and the Brock model in predicting the malignancy probability of SSNs, and the 3D model incorporating volume, mean CT attenuation value, and lobulation as factors performed the best.

Evaluation of pulmonary nodules by magnetic resonance imaging sequences: which sequence will replace computed tomography?

OBJECTIVE

This study aimed to determine the role of magnetic resonance imaging in minimizing radiation exposure, especially in the follow-up of pulmonary nodules.

METHODS

Patients who applied to our hospital between April 2013 and August 2018 for various reasons and had lung-mediastinal dynamic magnetic resonance imaging and thoracic computed tomography were included in the study. A total of 194 patients were included in the study, involving 84 females and 110 males. Scanning of the nodules was done retrospectively. This study was conducted by two readers: a thoracic radiologist with 15 years of experience and a nonspecific radiologist with 4 years of experience. Evaluations were made using the double-blind method.

RESULTS

Of the 194 patients, 84 (43.3%) were female and 110 (56.7%) were male. For the first reader, 135 (69.5%) nodules were detected in postcontrast T1 vibe images, 130 (67%) in T2 fast spin echo, 128 (66%) in precontrast T1 vibe, and 98 (50.5%) in T2 turbo inversion recovery magnitude sequence. For the second reader, 133 (68%) nodules were detected in postcontrast T1 vibe images, 120 (61.9%) in T2 fast spin echo, 122 (62.9%) in precontrast T1 vibe, and 99 (51%) in T2 turbo inversion recovery magnitude sequence. Capability levels were examined in detecting nodules between the first and second readers, and the ratios were reached at 0.92 in T2 fast spin echo, 0.81 in postcontrast T1 vibe images, 0.93 in precontrast T1 vibe, and 0.96 in T2 turbo inversion recovery magnitude sequence.

CONCLUSION

In this study of detecting pulmonary nodules by magnetic resonance imaging, which we performed with two different readers, one of whom was an experienced thoracic radiologist, both readers found the highest detection rate in the postcontrast T1 vibe sequence.

Calcification sign for prediction of benignity in pulmonary nodules: A meta-analysis

BACKGROUND

The calcification sign assessed by computed tomography appears to be a potential marker for benignities among patients diagnosed with pulmonary nodules (PNs). The following meta-analysis has been purposefully designed to figure-out the diagnostic value of the calcification signature as a way of identifying benignities from PNs.

METHODS

Cochrane Library, Embase and PubMed were considered as a reference to obtain the required data from January 2000 until October 2020. Stata v12.0 was used as a standard tool for statistical assessment.

RESULTS

Eleven retrospective studies were assessed via this meta-analysis, which included 6136 PNs (1827 benign and 4309 malignant). The pooled diagnostic odd ratios, positive likelihood ratio (PLR), negative likelihood ratio (NLR), sensitivity and specificity were 6.79, 6.06, 0.89, 13% and 98%, respectively. The value obtained for the area under the curve was 0.65, showing moderate overall diagnostic accuracy. A significant heterogeneity was found while calculating the pooled sensitivity (I²  = 85.5%), specificity (I²  = 75.0%), PLR (I²  = 59.0%), NLR (I²  = 79.5%) and DOR (I²  = 100.0%) in the current analysis. Sub-group analyses presented better PLR and specificity values for the study with a sample size ≥ 400. Deeks' funnel plot asymmetry test detected no potential evidence of significant publication bias (p = 0.091).

CONCLUSIONS

Calcification signs have been identified as moderate regulators corresponding to overall diagnostic performance (via marking a distinct differentiation between malignant and benign) for PNs. However, the manifestation of the calcification sign had a good directive property for benign PNs.

Cocaine-induced pulmonary complications: A diagnosis of waiting and watching

Pulmonary complications of cocaine among users are common. Manifestations include lung congestion, intra-alveolar edema, and diffuse alveolar hemorrhage (DAH). Direct cellular toxicity, eosinophilia, barotrauma, and vasoactive effects of cocaine are believed to induce DAH. We present a rare case of cocaine-associated focal alveolar hemorrhage mimicking malignancy on imaging. Initially contemplated biopsy was avoided based on rapid growth of concerning lung lesion, with subsequent near resolution on follow-up. This case illustrates the importance of epidemiologic and temporal multimodality correlation when evaluating indeterminate lung lesions.

Rare pulmonary tumors and carcinoma mimickers; experience from an interventional radiology unit with radiologic-pathologic correlation-A pictoral essay

BACKGROUND

Although imaging findings along with patients' clinical history may give clue for the etiology of a pulmonary lesion, the differentiation of benign pulmonary lesions from lung cancer could be challenging.

OBJECTIVE

The aim of this review article was to increase the awareness of the carcinoma mimicking lung lesions.

METHODS

This paper was designed to illustrate rare pulmonary tumors and carcinoma mimickers with emphasis on radiologic-pathologic correlation. Pitfalls encountered on CT images and also false positivity of PET-CT scans were also presented.

CONCLUSION

Several benign pulmonary lesions may grow in size on follow-up and some may show pathologic FDG (18F-fluorodeoxyglucose) uptake, which makes them indistinguishable from lung carcinoma by imaging. In addition, some slow-growing malignant lesions, such as carcinoid, may be false-negative on PET/CT scans.

Benign tumours of the bronchopulmonary system

The vast majority of tumours arising in the bronchopulmonary system are malignant in nature. Benign tumours of the lung are relatively rare and are often incidental findings during clinical investigations for unrelated conditions. These lesions can arise in the bronchial tree or the pulmonary parenchyma and may be of epithelial, mesenchymal, salivary gland-type or unknown differentiation. Although the spectrum of these lesions is wide, the clinical, pathological and immunohistochemical characteristics of the most relevant will be the subject of this review. In addition, the most important features allowing differentiation from malignant pulmonary neoplasms will be discussed.

Neoplastic pathology at the crossroads between neck imaging and cardiothoracic imaging

The thoracic inlet is located at the crossroads between imaging of the neck and the chest. Its location is an important anatomic landmark, serving as the central conducting pathway for many vital structures extending from the neck into the chest and vice versa. Many critical body systems, including the respiratory, lymphatic, neurologic, enteric, musculoskeletal, endocrine, and vascular systems, are located within this region. Neoplasms, both benign and malignant, can arise in any of the body systems located in this area. Due to the small size of this anatomic location, pathology is easily overlooked and imagers should be aware of the imaging appearance of these neoplasms, as well as which imaging modality is the most appropriate for neoplasm evaluation. This article will present an image rich, system-based discussion of the neoplastic pathology that can occur in this region. The anatomy of the thoracic inlet and the non-neoplastic pathology of the thoracic inlet have been covered in our companion article.

Visual assessment of calcification in solitary pulmonary nodules on chest radiography: correlation with volumetric quantification of calcification

PURPOSE

To assess the ability of digital chest radiography (CXR) to reveal calcification in solitary pulmonary nodules (SPNs), and to examine the correlation between a visual assessment and volumetric quantification of the calcification.

MATERIALS AND METHODS

This study was a retrospective review of 220 SPNs identified by both CXR and chest CT. Eleven observers did blind review of the CXR images and scored nodule calcification on a confidence scale of 1 to 5. The area under the receiver operating characteristics (ROC) curve (AUC) was obtained to analyze the diagnostic performance. The intraclass correlation coefficient (ICC) for interrater reliability was calculated. The AUC and ICC were calculated according to the following nodule diameter groups: group 1 (< 10 mm), group 2 (≥ 10 mm and < 20 mm), and group 3 (≥ 20 mm).

RESULTS

Of the 220 SPNs, 145 SPNs (65.6%) were identified as non-calcified and 75 (34.4%) as calcified. The average percentage of calcification volume in SPN > 160 HU (Vol160HU) among the 75 calcified nodules was 47.5%. The mean Vol160HU of the 68 SPNs classified as having definite calcification was 51.1%. The overall AUC was 0.71. The AUCs for groups 1, 2, and 3 was 0.835, 0.639, and 0.620, respectively. The ICCs for groups 1, 2, 3 was 0.65, 0.48, and 0.33, respectively.

CONCLUSION

The overall diagnostic performance of digital CXR to predict calcification in SPNs was moderately accurate and the diagnostic performance for predicting calcification in SPNs was significantly higher, and interobserver reproducibility was good when SPN < 10 mm compared with ≥ 10 mm in diameter.

KEY POINTS

• The misdiagnosis of a non-calcified nodule as a calcified one by CXR could lead to poor management choices for the SPN. • The diagnostic performance of CXR in predicting calcification was best for nodules < 10 mm in diameter. SPNs with calcification of approximately 50% of their volume tend to be considered calcified. • The diagnostic performance of CXR in identifying calcification was low for nodules ≥ 10 mm in diameter; therefore, we should carefully evaluate calcification carefully for nodules ≥ 10 mm.

The Solitary Pulmonary Nodule

Due to the high etiological diversity and the potential for malignancy, pulmonary nodules represent a clinical challenge, becoming increasingly frequent as the number of CT examinations rises. The topic gains even more importance as clear evidence for the effectiveness of CT screening was provided by the National Lung Screening Trial (NLST). Yet, the results were tempered by the high false-positive rate and the requirement of performing further diagnostic procedures. The management of those detected solitary pulmonary nodules is currently based on the individuals' risk of developing lung cancer, the pulmonary nodule characteristics and the capability of diagnostic and therapeutic approaches.

An update on the evaluation and management of small pulmonary nodules

The widespread utilization of chest CT scans has increased the importance of the proper evaluation of incidentally found lung nodules. The primary goal in the evaluation of these nodules is to determine whether they are malignant or benign. Clinical factors such as older age, tobacco smoking, and current or remote history of malignancy increase the pretest likelihood of malignancy. Radiological features of these nodules are important in differentiating benign from malignant lesions. However, the etiology of the lung nodules frequently remains indeterminate and requires further evaluation. The approach to the management of indeterminate lung nodules ranges between observation with repeat chest CT scan, further diagnostic studies such as PET scan or invasive procedures to obtain tissue diagnosis. This article reviews the importance of the different radiological features of lung nodules. This is followed by an update on the approach to the management of the different types of small lung nodules.

Primary lung and large airway neoplasms in children: current imaging evaluation with multidetector computed tomography

Multidetector computed tomography (MDCT) offers an important noninvasive imaging modality for confirmation and further characterization of primary lung and large airway neoplasms encountered in pediatric patients. Children represent a unique challenge in imaging, not only because of unique patient factors (eg, inability to follow instructions, motion, need for sedation) but because of the technical factors that must be optimized to reduce radiation dose. This article reviews an MDCT imaging algorithm, up-to-date imaging techniques, and clinical applications of MDCT for evaluating benign and malignant primary neoplasms of lung and large airway in infants and children.

A mathematical model for predicting malignancy of solitary pulmonary nodules

BACKGROUND

The goal of the present study was to differentiate between benign and malignant solitary pulmonary nodules (SPN) by developing a mathematical prediction model.

METHODS

Records from 371 patients (197 male, 174 female) with SPN between January 2000 and September 2009 were reviewed (group A). Clinical data were collected to estimate the independent predictors of malignancy of SPN with multivariate logistic regression analysis. A clinical prediction model was subsequently developed. Between October 2009 and May 2011, data from an additional 145 patients with SPN were used to validate this new clinical prediction model (group B). The same data were also estimated with two previously published models for comparison with our new model.

RESULTS

The median patient age was 57.1 years in group A; 54% of the nodules were malignant and 46% were benign. Logistic regression analysis identified six clinical characteristics (age, diameter, border, calcification, spiculation, and family history of tumor) as independent predictors of malignancy in patients with SPN. The area under the receiver operator characteristic (ROC) curve for our model (0.874 ± 0.028) was higher than those generated using the other two reported models. In our model, sensitivity = 94.5%, specificity = 70.0%, positive predictive value = 87.8%, and negative predictive value = 84.8%).

CONCLUSIONS

Age, diameter, border, calcification, spiculation, and family history of tumor were independent predictors of malignancy in patients with SPN. Our prediction model was sufficient to estimate malignancy in patients with SPN and proved to be more accurate than the two existing models.

Frequency and significance of pulmonary nodules on thin-section CT in patients with extrapulmonary malignant neoplasms

PURPOSE

To determine the frequency and significance of pulmonary nodules detected on thin-section CT in patients with extrapulmonary malignant neoplasms.

MATERIALS AND METHODS

The institutional review board approved this study. This study retrospectively evaluated 308 patients with extrapulmonary carcinomas or sarcomas and had undergone thin-section chest CT (2mm slice thickness) for staging. Three radiologists identified non-calcified nodules and evaluated the size, the growth and the distance from the nearest pleural surface. The characteristics of the nodules were defined based on the results of either a diagnostic biopsy or nodule growth.

RESULTS

One or more non-calcified pulmonary nodules were detected in 75% of the patients (233/308). One hundred and thirty-seven of these patients had nodules that met the criteria of either benign or malignant nodules. Nodules smaller than 10mm were more likely to be benign, whereas those 10mm or greater were more likely to be malignant (22/26, 85%; P<.0001). Most nodules less than 10mm from the pleura were benign (91%), whereas approximately half of the nodules 10mm or more away from the pleura were malignant (20/43, 47%; P<.0001). Patients with melanoma, sarcoma, or testicular carcinoma were more likely to have malignant nodules. A multivariable analysis demonstrated the nodule size (P<.0001) and distance from the pleura were predictive of malignancy.

CONCLUSION

The nodule detection rate on thin-section CT in patients with extrapulmonary malignancy is high. Most of the nodules smaller than 10mm or less than 10mm from the pleura are benign.

Surgical treatment and outcome of pulmonary hamartoma: a retrospective study of 20-year experience

BACKGROUND

Controversy still exists in the indication and timing of surgical treatment of pulmonary hamartoma (PH). The objective of this study is to summarize the experience and the outcome of the surgical treatment for pulmonary hamartomas, and to assess the effectiveness and necessity of surgical therapy administered in patients with pulmonary hamartoma as well as clinical and pathological features and long-term follow-up results.

METHODS

This retrospective report has reviewed a 20-years clinical history of surgical treatment for 39 patients with PH from 1985 to 2006. These thirty-nine patients underwent 40 operations as follows: wedge resection (23), enucleation (10), segmentectomy (3), lobectomy (3), and pneumonectomy (1).

RESULTS

The PH occurred most frequently (78.1%) in the patients aged 40 to 60 years and the sex ratio (male/female) was 2.25/1 in our series. No postoperative death was encountered. One patient with pleural effusion was cured after thoracentesis. All of these 39 patients were proved with pathologic diagnosis of PH and the popcorn calcification was found in 6 cases before operation. In 38 cases having the mean follow-up of 7.3 years, a patient was operated thrice for regional recurrence.

CONCLUSION

Fast frozen section in operation is critical for acquire accurate pathological diagnosis. Due to potential trend of recurrence or malignancy, patients with hamartoma should be submitted to a complete evaluation and a regular follow-up.

Distinguishing benign from malignant pulmonary nodules with helical chest CT in children with malignant solid tumors

PURPOSE

To retrospectively assess whether computed tomographic (CT) findings can indicate the benign or malignant nature of pulmonary nodules in pediatric patients with malignant solid primary tumors.

MATERIALS AND METHODS

With institutional review board approval, waived parental and patient consent, and HIPAA compliance, the authors determined the incidence of malignancy among 81 pulmonary nodules that were sampled at biopsy within 3 weeks after chest CT (January 1999 to September 2003) in 41 young patients with malignant solid tumors. Three radiologists independently and retrospectively reviewed these scans and the available previously obtained scans, classifying nodules as benign, malignant, or indeterminate on the basis of their number, unilateral versus bilateral distribution, size, margins (indistinct vs distinct), calcification, growth, and associated adenopathy. These classifications were compared with nodule histologic type, and interreviewer agreement was assessed.

RESULTS

The median patient age was 14.8 years (mean, 13.7 years; range, 5-21 years). Twenty-four of the 41 patients (58%) had at least one biopsy-proved malignant nodule. Four (10%) patients had both benign and malignant nodules; 17 (42%) had only benign nodules. Reviewer 1 classified 65% (39 of 60) of nodules correctly; reviewer 2, 57% (37 of 65); and reviewer 3, 67% (43 of 64). Interreviewer agreement was slight to moderate (kappa </= 0.43, P </= .03). In contrast to findings in adults, sharply defined nodules in younger individuals were more likely to be malignant (P = .03) and nodule size was not associated with malignancy (P >/= .32).

CONCLUSION

The frequency of benign nodules and the inconsistency of predictions based on CT features suggest the need for better predictors of pulmonary nodules being malignant or benign, so as to reduce unnecessary thoracotomy in pediatric patients with solid malignancy. .

The solitary pulmonary nodule

The imaging evaluation of a solitary pulmonary nodule is complex. Management decisions are based on clinical history, size and appearance of the nodule, and feasibility of obtaining a tissue diagnosis. The most reliable imaging features are those that are indicative of benignancy, such as a benign pattern of calcification and periodic follow-up with computed tomography for 2 years showing no growth. Fine-needle aspiration biopsy and core biopsy are important procedures that may obviate surgery if there is a specific benign diagnosis from the procedure. In using the various imaging and diagnostic modalities described in this review, one should strive to not only identify small malignant tumors--where resection results in high survival rates--but also spare patients with benign disease from undergoing unnecessary surgery.

The solitary pulmonary nodule

The solitary pulmonary nodule will be found increasingly by the use of newer imaging techniques, including computed tomography (CT) screening. The aim must be to have an approach that avoids unnecessary surgery or biopsy with their attendant risks. Plain films characterisation, CT assessment, including densitometry and enhancement, and growth patterns are discussed and evaluated. The use of Bayes theorem to guide these assessment strategies is also described.

Atypical lipomatous tumour (lipoma-like well-differentiated liposarcoma) arising in a pulmonary hamartoma and clinically presenting with pneumothorax

We document an uncommon variant of pulmonary hamartoma (PH), discovered in the left upper lobe of a 60-year-old man after an episode of pneumothorax, a unique clinical presentation for such an occurrence. The tumour showed a prominent leaf-like pattern and was mainly composed of mature fat with adipocytes of different size and scattered throughout lipoblasts and floret-like cells. A lobectomy was performed and more than 7 years after surgery the patient's course is still uneventful. This case represents an exceedingly rare example of an histologically malignant change in PH and bears a close clinicopathologic resemblance to atypical lipomatous tumours of soft tissues.

Unusual primary lung neoplasms

Bronchial carcinoids and hamartomas are, respectively, the most common malignant and benign unusual primary lung neoplasms. These tumors are often asymptomatic but can cause central airway obstruction. Helical computed tomographic and radionuclide scintigraphic advances in their detection and evolution, together with newer interventional bronchoscopy techniques such as neodymium:yttrium-aluminum-garnet laser phototherapy and cryotherapy, represent important improvements in the diagnosis and management of patients with such tumors.

Computerized analysis of the likelihood of malignancy in solitary pulmonary nodules with use of artificial neural networks

PURPOSE

To develop a computer-aided diagnostic scheme by using an artificial neural network (ANN) to assist radiologists in the distinction of benign and malignant pulmonary nodules.

MATERIALS AND METHODS

Fifty-six chest radiographs of 34 primary lung cancers and 22 benign nodules were digitized with a 0.175-mm pixel size and a 10-bit gray scale. Eight subjective image features were evaluated and recorded by radiologists in each case. A computerized method was developed to extract objective features that could be correlated with the subjective features. An ANN was used to distinguish benign from malignant nodules on the basis of subjective or objective features. The performance of the ANN was compared with that of the radiologists by means of receiver operating characteristic (ROC) analysis.

RESULTS

Performance of the ANN was considerably greater with objective features (area under the ROC curve, Az = 0.854) than with subjective features (Az = 0.761). Performance of the ANN was also greater than that of the radiologists (Az = 0.752).

CONCLUSION

The computerized scheme has the potential to improve the diagnostic accuracy of radiologists in the distinction of benign and malignant solitary pulmonary nodules.

Benign intrathoracic tumours. A population survey in northern Finland

Benign intrathoracic tumours are uncommon, but their occurrence in unselected populations is poorly defined. We reviewed all cases of suspected intrathoracic tumour in a population (440,000) in northern Finland during 1990 through 1992. Diagnostic investigations included fiberoptic bronchoscopy and computed tomography in all cases. Of the 653 intrathoracic tumours, 36 were benign. The male/female ratio in these 36 cases was 1.25; the mean age was 54 years. Twenty-three of the lesions were symptomless, found at health check or examination for other disease. Bronchoscopy did not confirm the diagnosis of any benign tumour. Thoracotomy was considered necessary in most cases and histologic diagnosis was therefore available in 24 (67%). Hamartoma was the most common benign lung tumour. This prospective study in an unselected population confirms previous findings in surgical series concerning benign intrathoracic tumours and their histology.

Approach to the solitary pulmonary nodule

Because many malignant and benign processes may manifest as a solitary pulmonary nodule on a chest roentgenogram, this finding presents a diagnostic challenge. The major concern is whether the lesion is malignant. The likelihood of a malignant tumor correlates with the age of the patient, the size of the nodule, a history of a prior malignant lesion, and a history of smoking. Recent advances in radiologic techniques, such as the detection of calcium or the inference of the presence of calcium by high attenuation values on computed tomography, provide assistance in identifying benign lesions. The history, physical examination, and radiographic information can help determine an appropriate course of action. The goals are to remove malignant nodules promptly and to avoid surgical intervention in patients whose nodules are benign.

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)

Evaluation of pulmonary and mediastinal masses

This article discusses the radiographic evaluation of pulmonary and mediastinal masses by the following modalities: plain radiography, fluoroscopy, conventional tomography, computed tomography, and magnetic resonance imaging. The author surveys digital and conventional angiographic techniques for assessing vascular masses within the thorax, and discusses the role of percutaneous needle biopsy of the thorax.

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.

Benign tumors of the lung and bronchus

Benign tumors of the lung and bronchus are a heterogeneous group of lesions that usually present as asymptomatic, solitary, peripheral lung nodules or, less commonly, as endobronchial lesions causing obstructive symptoms. All endobronchial lesions should be removed surgically to alleviate symptoms and to prevent destruction of distal lung tissue. Parenchymal lesions may present challenging problems in clinical diagnosis and management. Most patients will ultimately require thoracotomy for histologic confirmation of benignity. It is probable that newer diagnostic procedures will allow a more accurate nonoperative diagnosis in certain patients in the near future. At the present time, expeditious limited thoracotomy affords a safe, rapid, and effective treatment for patients with a benign tumor of the lung or bronchus.

Peripheral pulmonary carcinoid tumors

The light microscopic and ultrastructural features of five asymptomatic peripheral carcinoids presented as distinct pulmonary solitary nodules are described. By conventional microscopy the tumors displayed a variety of histologic patterns, the most unusual one showing tumor cells embedded in a richly vascular hyalinized stroma and forming papillary structures or cystic spaces lined by low cuboidal cells which ultrastructurally bore a strong resemblance to intermediate or transitional forms between types I and II pneumocytes. A striking feature of these tumors was their rich vasculature associated with a marked perivascular sclerosis composed of basement membrane-like material and collagen fibrils most likely produced by the increased numbers of pericytes surrounding these sclerotic vessels. The clinical implications, biologic behavior, and association of these tumors with other pulmonary neoplasms are also discussed.

Pulmonary arteriovenous fistula. A review

A successfully treated case of an arteriovenous fistula of the lung is reported. An exhaustive review is made of the pertinent literature and the pathophysiology, embryology, clinical aspects, diagnosis and treatment are discussed.