PET/CT assessment of neuroendocrine tumors of the lung with special emphasis on bronchial carcinoids.

Pulmonary neuroendocrine tumors (pNETs) arise from bronchial mucosal cells known as enterochromaffin cells which are part of the diffuse neuroendocrine system. The pathological spectrum of pNETs ranges from low-/intermediate-grade neoplasms such as bronchial carcinoids (BCs), also known as typical or atypical carcinoids, to high-grade neoplasms as large-cell neuroendocrine carcinoma and small-cell lung cancer. The tumor biology of pNETs still represents a matter of open debate. The distinct features among the different pNETs include not only their pathologic characteristics but also their clinical behavior, epidemiology, treatment, and prognosis. In this sense, a correct pathological identification in the preoperative setting is a key element for planning the best strategy of care in pNETs and especially in BCs. Controversial results have been reported on the diagnostic accuracy of fluorine-18-fluorodeoxyglucose positron emission tomography or positron emission tomography/computed tomography (F-18-FDG PET or PET/CT) in BCs. On the other hand, there is increasing evidence supporting the use of PET with somatostatin analogues (DOTA-TOC, DOTA-NOC, or DOTA-TATE) labeled with gallium-68 (Ga-68) in pNETs. Herein, we review the pertinent literature aiming to better define the current state of art of PET/CT in the detection and histological differentiation of pNETs with special emphasis on BCs.

[Multidetector computed tomography assessment of the degree of differentiation of bronchial carcinoid tumors]. / Hallazgos radiológicos en tomografía computarizada de los tumores carcinoides bronquiales típicos y atípicos.

OBJECTIVE: To define the CT findings for bronchial carcinoid tumors and to determine whether these findings enable these tumors to be classified as typical or atypical. MATERIAL AND METHODS: We reviewed the chest CT studies performed between 1 January 2001 and 31 December 2009 in patients at our hospital diagnosed with bronchial carcinoid tumors. The sample consisted of 52 patients (23 women and 29 men) with a mean age of 47 years (range 11-77 years). The 52 cases were classified as typical or atypical on the basis of the following radiological findings: size, location, focality, type of growth, calcifications, signs secondary to bronchial obstruction, and the presence of significant lymph node enlargement or metastases. These findings were then compared with the histological findings. RESULTS: Typical carcinoid tumors were the most prevalent (46 cases). The variables associated with atypical tumors were: male sex, advanced age at onset, and size >3cm. The accuracy of CT in classifying atypical tumors correctly increased with the number of variables indicative of atypical carcinoid tumors. A negative result for atypical nature made it possible to rule out an atypical carcinoid tumor in 95% of the cases. CONCLUSION: CT is useful for defining and characterizing carcinoid tumors into typical or atypical, although a precise formula for differentiating between the two types remains to be defined.

Radiologic signs in thoracic imaging: case-based review and self-assessment module.

OBJECTIVE: Chest imaging remains one of the most complicated sub-specialties of diagnostic radiology. The successful interpretation of thoracic imaging studies requires the recognition and understanding of the radiologic signs that are characteristic of many complex disease processes. CONCLUSION: The educational objectives for this case-based self-assessment module are for the participant to exercise, self-assess, and improve his or her understanding of important thoracic radiologic signs that are useful in establishing the diagnosis of particular diseases of the chest.

Gangliocytic paraganglioma of the bronchus: a case report with follow-up and ultrastructural assessment.

We report a case of gangliocytic paraganglioma of bronchus. A 54-year-old woman underwent bronchoscopy following two episodes of right lower lobe pneumonia over the previous 5 months with unresolved chest radiographic changes. A computerized tomographic scan showed a right lower lobe endobronchial lesion, and at bronchoscopy there was a mass partly occluding the lumen of the bronchus. The biopsy and subsequent bronchoscopic resection showed a tumor with morphologic, immunohistochemical, and ultrastructural features of paragangliomatous, gangliocytic, and Schwann cell differentiation consistent with a gangliocytic paraganglioma. The lesion was treated conservatively with bronchoscopic resection and laser therapy. Histopathologic examination of recurrent tumor at 6 months showed features consistent with paraganglioma. Ten months after initial diagnosis, there was no bronchoscopic evidence of residual tumor. The occurrence of gangliocytic paraganglioma in diverse sites gives cause for the reappraisal of the histogenesis of this fascinating lesion. The variable morphology of this lesion may be an expression of the potential for divergent differentiation of a pluripotent stem cell.

Preoperative bronchoscopic assessment of airway invasion by esophageal cancer: a prospective study.

BACKGROUND: Bronchoscopy is frequently used to assess invasion of esophageal cancer into the tracheobronchial tree. Prospective studies evaluating the role of bronchoscopy in pretherapeutic staging of esophageal cancer are lacking. STUDY OBJECTIVES: To evaluate the diagnostic utility of fiberoptic bronchoscopy for the assessment of airway involvement by esophageal carcinoma and its resectability. PATIENTS AND METHODS: In a prospective study, we analyzed 150 bronchoscopies in 116 consecutive patients with potentially operable esophageal carcinoma, and correlated the findings with other staging modalities, intraoperative evaluation, and histopathologic data. RESULTS: One unknown additional bronchial cancer was found. In 32% of bronchoscopies performed in patients with esophageal cancer located above the tracheal bifurcation, some macroscopic abnormality was detected in the trachea and main bronchi, with mobile protrusion of the posterior tracheal wall being the most frequent abnormality (20.7%). When compared with histologic results, normal macroscopic appearance of the trachea and main bronchi had a negative predictive value of 98.5%, but the positive predictive value of all macroscopic abnormalities for the diagnosis of airway involvement was low, particularly after radiation therapy. The overall accuracy of bronchoscopy with multiple brush cytology and biopsy sampling in proving or excluding airway invasion in patients with otherwise operable conditions was 95.8% (95% confidence interval, 88.3 to 99.1%). Bronchoscopy was the sole decisive staging procedure, resulting in exclusion from surgery because of airway invasion, in 9.7% of patients with otherwise potentially operable conditions. The results of bronchoscopy and CT were discordant in 40% of the patients; the specificity and positive predictive value were higher for bronchoscopy than for CT. CONCLUSIONS: When performed as the last investigation in the staging workup, bronchoscopy with biopsy and brush cytology is a very accurate procedure in evaluating possible airway invasion of esophageal cancer; macroscopic findings alone are not reliable.

Scintigraphic assessment of pituitary adenomas and several diseases by indium-111-pentetreotide.

The aim of this study was to identify the specific somatostatin receptors expressed by several tumors, utilizing 111In-octreotide, a long acting somatostatin analogue. We studied two different groups of patients: the first group was composed of 21 patients suffering from different pituitary adenomas, while the second group consisted of 12 patients affected by several different neoplasms. In vivo scintigraphy showed pentetreotide receptors only in large GH-secreting adenomas and several macroadenomas. Concerning the endocrine activity of the adenomas, 111In-octreotide showed a good sensibility in detecting GH-secreting tumors. In the second group, 111In-octeotride proved to be a good diagnostic tool to show carcinoid lesions which were missed by other complementary methodologies.

Bronchial carcinoid tumors: assessment with CT of location and intratumoral calcification in 31 patients.

Bronchial carcinoid tumors (BCT) have long been regarded as predominantly central and rarely calcified. The authors retrospectively reviewed computed tomographic (CT) findings in 31 patients (thin-section CT studies in 18) who were seen at their institution with the histopathologic diagnosis of BCT (27 typical, four atypical) during the years 1978-1989. Eighteen BCT (58%) were central and 13 (42%) peripheral, with peripheral defined as located more than 2 cm distal to the origin of the appropriate segmental bronchus. CT scans revealed varied patterns of calcification in seven (39%) of the 18 central BCT and in one (8%) of the 13 peripheral BCT (P less than .1); overall, CT scans revealed calcification in eight (26%) of the BCT. The eight calcified tumors were each of the typical histopathologic type. Peripheral BCT (42%) were nearly as common as central BCT (58%), and CT detection of calcification in BCT was not uncommon (39% of central lesions; 26%, overall).

Accuracy of computed tomographic scanning in assessment of the mediastinum in bronchial carcinoma.

We believe that malignant involvement of mediastinum is a contraindication to attempted resection of bronchial carcinoma. It was hoped that computed tomographic (CT) scanning might improve our ability to assess the mediastinum prior to thoracotomy. The accuracy of CT scanning, performed with modern techniques, in assessment of the mediastinum of 22 patients with bronchial carcinoma has therefore been determined. In all the patients CT scan impressions have been correlated with the histologic findings at thoracotomy or mediastinoscopy. In detection of malignant involvement of the mediastinum, the CT scan had a sensitivity of 80% and a specificity of 76%. There was only one false negative CT scan report, and in this case the mediastinum was involved at a site which could not have been inspected at anterior cervical mediastinoscopy. We conclude that a negative CT scan makes mediastinoscopy an unnecessary screening procedure in determining resectability. Since there was a significant number of false positive CT scans, we feel that such a report necessitates tissue confirmation before the decision to withhold thoracotomy is made. The CT scan may help to determine the best test to achieve this tissue confirmation.

Computerized axial tomography in the pretreatment assessment of small-cell carcinoma of the bronchus.

Computerized axial tomographic scans (CAT scans) of thorax and abdomen were used as part of the initial staging procedure of 50 consecutive patients with small-cell bronchogenic carcinoma (SCBC). The aims were to define the extent of the primary tumor and metastatic spread, and to compare the information obtained from CAT scans with conventional staging procedures. With CAT scanning, spread of the primary tumor was found to be far more extensive than originally believed when defined by conventional assessment. Of 35 patients conventionally staged as localized T1 or T2 tumors, 27 (77%) had their stage increased to extensive T3 disease. similarly, subcarinal lymph nodes were found in one patient when conventional methods were used (2%), but 16 patients (32%) were found when CAT scan was used. Unsuspected adrenal metastases were found in eight patients (16%) and retrocrural nodes in four patients (8%). Thirty-seven patients (74%) were found to have Stage III tumors when conventional staging was used; 47 patients (94%) were found to be Stage III following CAT scanning, demonstrating that, within the thorax, localized tumors are very uncommon. CAT scanning demonstrates the degree of intrathoracic spread very clearly, and has a valuable role in the initial investigation of patients with SCBC if the planned treatment includes radiotherapy.

Ventilation and perfusion scans in the preoperative assessment of bronchial carcinoma.

Ventilation (krypton -81m) and perfusion (technetium -99m) lung scans were obtained in a consecutive series of 21 patients shortly before thoracotomy for proven or suspected carcinoma of the bronchus. In most patients ventilation and perfusion were impaired equally and the scan abnormality corresponded to the bronchoscopic and radiological findings. Unexpectedly large defects in the perfusion scan were seen in three patients, all of whom had extensive neoplastic involvement of the mediastinum at thoracotomy, but 11 other patients had mediastinal involvement which was not suspected from the scan. Ventilation scanning was useful in the prediction of postoperative ventilatory capacity in two patients who underwent pneumonectomy. We conclude that ventilation and perfusion scans are not sensitive indicators of neoplastic involvement of the mediastinum but they are valuable for the prediction of postoperative lung function.

[Mediastinoscopy in preoperative assessment of operability in patients with bronchial neoplasms (author's transl)]. / Die Mediastinoskopie in der präoperativen Beurteilung der Operabilität des Bronchialkarzinoms

The results and conclusions of the endoscopic exploration of mediastinum in 352 patients suffering from bronchogenic cancer are analysed. The importance of mediastinoscopy is emphasized especially in the assessment of operability. In the opinion of the authors the cancer is not operable, if metastases are found in the paratracheal and contralateral lymphnodes. Only in young men the extended resection should be done in individual cases if mediastinal lymphnode metastases are detected. Regarding these indications the rate of explorative thoracotomy could be reduced to 10%. The particular importance of preoperative examination of load capacity of the heart and circulatory system is stressed. Finally it is concluded, that an decisive improvement of the common prognosis of the bronchogenic cancer is only possible by an earlier detection and a more rapid introduction of therapy, but not by the extension of the surgical procedures. The enlargement of the surgical procedure should be decided individually. The great possibilities hencefollowing for the mass x-ray examinations are emphasized.