Neuroendocrine carcinoma of the posterior mediastinum arising from a foregut cyst

Posterior mediastinal nodule diagnosed as a tuberculous granuloma infiltrating into the aorta

Although tuberculous infection rarely results in aortic aneurysm formation or rupture, its precursor lesion has never been identified in cases with tuberculosis. We incidentally encountered a case of a posterior mediastinal nodule with concomitant chest computed tomography (CT) findings of multiple pulmonary micronodular shadows. Since an enlargement of the mediastinal nodule was retrospectively apparent, we considered the lesion as malignant. Enhanced CT showed luminal irregularity in the descending aorta, located adjacent to the nodule, in addition to the disappearance of the fat plane between the lesion and the aorta. We successfully resected the nodule with the aorta under partial cardiopulmonary bypass. Based on the pathological and postoperative bacterial findings, the nodule was diagnosed as a tuberculous granuloma infiltrating into the medial layer of the aorta.

Primary small cell neuroendocrine carcinoma of the mediastinum: computed tomography and histopathological correlation

OBJECTIVES

The objectives of this study were to describe the computed tomographic (CT) and histopathological characteristics of neuroendocrine carcinomas of the mediastinum and to improve the diagnostic accuracy for these tumors.

MATERIALS AND METHODS

We retrospectively analyzed 9 patients with histopathologically confirmed primary small cell neuroendocrine carcinoma of the mediastinum.

RESULTS

Of the 9 tumors, 6 (67%) were located in the anterior-middle mediastinum; 2, in the anterior-middle-posterior mediastinum; and 1, in the middle-mediastinum. Eight tumors appeared inhomogeneous on CT, with large areas of necrosis, whereas 1 tumor had a uniform density. Four tumors (44%) had scattered punctate calcifications. Moderate, heterogeneous enhancement (range, 21-34 Hounsfield units) was present in 8 patients. All tumors compressed or invaded the adjacent mediastinal structures. Hematoxylin and eosin staining results revealed small tumor cells, with little cytoplasm, pale chromatin, and inconspicuous or absent nucleoli. Immunohistochemical analysis results showed that the tumor cells were positive for chromogranin A, synaptophysin, and neuron-specific enolase.

CONCLUSIONS

A large tumor located in the anterior-middle mediastinum, showing scattered punctate calcifications and compressing or invading the adjacent mediastinal structures, should arouse suspicion for a small cell neuroendocrine carcinoma. However, the diagnosis of such tumors requires a combination of pathological and immunohistochemical examination.

Adenocarcinoma arising in a mediastinal enteric cyst

A 39 year-old male was admitted to our hospital because of relapsing episodes of pneumonia. His chest roentgenogram showed a consolidated shadow and cavity formation in the left lower lobe. During a left lower lobectomy an enteric cyst in the posterior mediastinum involving lung was found. This cyst in the lung contained normal gastric parietal cells and pancreatic tissue, and was surrounded by adenocarcinoma characteristic of gastric cancer. This is a rare case in which an adenocarcinoma arise from an enteric cyst in the mediastinum.