Gregory L. Aughenbaugh

Utility of Integrated Computed Tomography—Positron Emission Tomography for Selection of Operable Malignant Pleural Mesothelioma

BACKGROUND Malignant pleural mesothelioma (MPM) is a primary malignancy characterized by local invasion of the pleura and metastasis. Despite advances in computed tomography (CT) and magnetic resonance imaging (MRI), accurately staging patients remains challenging. Recent studies have examined the use of integrated CT-positron emission tomography (PET) for staging patients. MATERIALS AND METHODS Mayo Clinic databases were queried to identify cases with a histologic diagnosis of MPM from 2000 to 2006. Inclusion criteria were a diagnosis of MPM, an available CT scan, and an initial staging integrated CT-PET scan. A total of 35 patients were identified who met the inclusion criteria. Computed tomography and integrated CT-PET scans were reviewed by experienced radiologists. Laboratory parameters were reviewed. The Mayo Clinic tumor registry and Social Security database were queried for survival data in patients in which no follow-up was available. RESULTS Findings on integrated CT-PET excluded 14 of 35 patients from surgical intervention. Extrapleural pneumonectomies (EPPs) were performed in 8 patients, and partial pleurectomies were performed in 2 patients. Upstaging from integrated CT-PET occurred in 70% of the patients when surgical pathology was available, 2 cases to an inoperable stage. Although not statistically significant, median survival was 20 months for patients undergoing an EPP and 12 months for patients excluded from surgical intervention by integrated CT-PET. CONCLUSION Malignant pleural mesothelioma is a difficult disease to accurately stage. The most common reason for upstaging in our series was an increase in T (tumor; tumor-node-metastasis staging system) disease. Our data suggest that integrated CT-PET is excellent for detecting nodal and distant metastases. However, the ability of this imaging modality to correctly stage locoregional disease is not superior to the combination of CT and MRI as reported in the literature.

Primary Mediastinal Neoplasms (Other Than Thymoma)

Primary mediastinal neoplasms encompass a long list of histologically diverse lesions that can arise from a wide variety of mediastinal structures. Recent advances in diagnostic techniques have considerably enhanced the evaluation of the mediastinum with use of noninvasive or minimally invasive procedures. In adults, most primary mediastinal neoplasms can be classified in one of four categories: thymus-derived neoplasms, neurogenic tumors, lymphomas, or germ cell neoplasms. In children, neurogenic tumors (especially neuroblastomas) and lymphomas are most frequently encountered. Because of the presence of many vital structures in the confined thoracic cavity, even benign mediastinal neoplasms can cause severe symptoms from the mass effect and therefore warrant a carefully planned management strategy. With modern therapeutic and surgical interventions, associated morbidity and mortality can often be substantially decreased.

CT reconstruction algorithm selection in the evaluation of solitary pulmonary nodules

Objective We have observed a significant CT artifact in the evaluation of lung nodules that occurred with the use of high-spatial-frequency reconstruction algorithms. We have seen this lead to a false-positive diagnosis of calcification in a small uncalcified lung nodule. Because of the seriousness of misinterpretation of benign calcification in an uncalcified nodule, we reviewed the various effects of several reconstruction algorithms on different scanners. Materials and Methods Using high-spatial-frequency, smoothing, and intermediate reconstruction algorithms, we studied standardized cylinders in a CT reference phantom and lung nodules in eight patients. Algorithms on four CT scanners were analyzed. Results We found peripheral edge enhancement artifact on some CT images of phantom cylinders and uncalcified lung nodules. The images with edge enhancement artifact were obtained from two scanners with the use of high-spatial-frequency algorithms (Picker 1200 SX and GE HiSpeed Advantage). Conclusion Use of high-spatial-frequency reconstruction algorithms for the analysis of lung nodules with thin-section CT may lead to an erroneous diagnosis of calcification.

Glomus tumor of the trachea: Value of multidetector computed tomographic virtual bronchoscopy

Glomus tumor of the trachea is extremely rare. We report a case of tracheal glomus tumor in a 39-year-old man who presented with hemoptysis. The diagnosis was made after bronchoscopic biopsy of a tumor involving the posterior wall of the upper trachea. Thin-section multidetector computed tomography of the chest was performed before surgical resection, with multiplanar re-formations and 3-dimensional virtual bronchoscopic reconstruction. Tracheal sleeve resection with reconstruction was successful, and pathological studies confirmed complete resection and the diagnosis of glomus tumor. The patient was disease-free 3 months postoperatively. To our knowledge, this is the first reported case in which additional computed postprocessing was used to help evaluate the extent of such a tumor.

Pulmonary Necrotizing Granulomas of Unknown Cause: Clinical and Pathologic Analysis of 131 Patients With Completely Resected Nodules

BACKGROUND The cause of pulmonary necrotizing granulomas is often unclear, even after histologic examination. Our aim was to determine the clinical significance of histologically unexplained necrotizing granulomas. METHODS Pulmonary necrotizing granulomas surgically resected at the Mayo Clinic (1994-2004) were retrieved and reviewed retrospectively. Cases in which a cause was evident at the time of initial histologic examination were excluded. The analysis cohort comprised 131 completely resected histologically unexplained pulmonary necrotizing granulomas. Clinical and laboratory information was abstracted from medical records, chest CT scans were reviewed, histologic slides were reexamined, and additional ancillary studies were performed in selected cases. RESULTS A cause was determined on review in more than one-half of the histologically unexplained necrotizing granulomas (79 of 131, 60%) by reexamining histologic slides (47), incorporating the results of cultures (26), fungal serologies (14), and other laboratory studies (eight), and correlating histologic findings with clinical and radiologic information (13). Infections accounted for the majority (64 of 79), the most common being histoplasmosis (37) and nontuberculous mycobacterial infections (18). Noninfectious diagnoses (15 of 79) were rheumatoid nodule (five), granulomatosis with polyangiitis (Wegener) (five), sarcoidosis (four), and chronic granulomatous disease (one). Many cases remained unexplained even after extensive review (52 of 131, 40%). Most of these patients received no medical therapy and did not progress clinically or develop new nodules (median follow-up, 84 months). CONCLUSIONS A cause, the most common being infection, can be established in many surgically resected pulmonary necrotizing granulomas that appear unexplained at the time of initial histologic diagnosis. Patients whose granulomas remain unexplained after a rigorous review have a favorable outcome. Most do not develop new nodules or progress clinically, even without medical therapy.

High-Resolution Computed Tomography of the Lung

High-resolution computed tomography (HRCT) and thin-section CT are techniques that are particularly suited for evaluation of the pulmonary parenchyma. These techniques have been found useful in the assessment of bronchiectasis and solitary pulmonary nodules. HRCT offers promise in evaluation of diffuse and focal pulmonary parenchymal disease. The principles and applications of HRCT of the lung are reviewed.

Computed tomography of benign mature teratomas of the mediastinum

The computed tomography (CT) findings of five benign, mature teratomas of the anterior mediastinum collected during a ten-year period are described, and their case histories are reviewed. Three of the five were primarily cystic, with only small soft tissue components. One of the five contained equal cystic and solid elements. All cysts had a higher attenuation than water. Three tumors contained small foci of dense calcification or ossification. Only two contained fat. Computed tomography accurately predicted the presence of adherence to adjacent structures in all five. Four of five patients were less than 22 years of age, and benign teratoma of the mediastinum was not a common neoplasm at any age. The origin and pathology of germ cell tumors of the mediastinum are briefly reviewed.

Carcinoid Tumors and Sarcoidosis—Does a Link Exist?

OBJECTIVE To attempt to determine whether a relationship exists between carcinoid tumors and sarcoidosis. MATERIAL AND METHODS We present a series of seven case reports and discuss hypotheses about possible disease associations. RESULTS Certain malignant lesions have tended to occur in patients with sarcoidosis. Seven patients who were encountered at Mayo Clinic Rochester between 1950 and 1994 had both sarcoidosis and carcinoid tumors. These patients ranged in age from 31 to 66 years, and three of the patients had a history of benign thyroid disorders. Malignant tumors have been thought to be related to sarcoidosis in one of two ways: (1) immunologic abnormalities in sarcoidosis may promote the development of neoplasms or (2) malignant disease may promote the onset of sarcoidosis either by causing local sarcoid reactions that progress or by directly initiating the manifestations of systemic sarcoidosis. Because the chronology of events differed in our seven cases, various mechanisms of action may have a role in the manifestations of these two disease entities. Our cases emphasize the importance of avoiding the diagnosis of disseminated malignant disease in patients with cancer and associated hilar and mediastinal lymphadenopathy without biopsy confirmation of metastatic disease. CONCLUSION Application of the knowledge gained about the mechanisms of disease in sarcoidosis will perhaps facilitate identification of the pathogenesis of carcinoid tumors and other neuroendocrine tumors.

Solitary Pulmonary Metastasis Presenting 20 Years After Primary Resection of Wilms Tumor

Wilms tumor is the most common renal malignancy of childhood. Relapse occurs most often within 4 years of initial diagnosis, and the most common site of metastasis is the lung. We describe a 22-year-old man who presented with hemoptysis and a solitary pulmonary lesion 20 years after primary resection of Wilms tumor. Computed tomography of the chest showed an indeterminate pulmonary mass of heterogeneous attenuation with no other intrathoracic abnormalities. Surgical resection revealed a solitary pulmonary metastasis from Wilms tumor. Further evaluation yielded no evidence of extrathoracic metastases. This case shows that late relapse in the form of a solitary pulmonary mass can occur in patients with Wilms tumor.

Screening for lung cancer with low-dose spiral computed tomography

Studies suggest that screening with spiral computed tomography can detect lung cancers at a smaller size and earlier stage than chest radiography can. To evaluate low-radiation-dose spiral computed tomography and sputum cytology in screening for lung cancer, we enrolled 1,520 individuals aged 50 yr or older who had smoked 20 pack-years or more in a prospective cohort study. One year after baseline scanning, 2,244 uncalcified lung nodules were identified in 1,000 participants (66%). Twenty-five cases of lung cancer were diagnosed (22 prevalence, 3 incidence). Computed tomography alone detected 23 cases; sputum cytology alone detected 2 cases. Cell types were: squamous cell, 6; adenocarcinoma or bronchioalveolar, 15; large cell, 1; small cell, 3. Twenty-two patients underwent curative surgical resection. Seven benign nodules were resected. The mean size of the non-small cell cancers detected by computed tomography was 17 mm (median, 13 mm). The postsurgical stage was IA, 13; IB, 1; IIA, 5; IIB, 1; IIIA, 2; limited, 3. Twelve (57%) of the 21 non-small cell cancers detected by computed tomography were stage IA at diagnosis. Computed tomography can detect early-stage lung cancers. The rate of benign nodule detection is high.