A case of follicular thyroid cancer with tracheal stenosis responded to external radiation therapy.

We report the case of a 70-year-old man with follicular carcinoma of the thyroid who complained of worsening dyspnea and was successfully treated by external radiation therapy. The total dose given was 61 Gy in 28 fractions. This case suggests that external radiation therapy is effective for the management of differentiated thyroid cancer with critical stenosis of the trachea that is inoperable and difficult to treat with radioiodine.

Osseous primitive neuroectodermal tumor--a case report.

PNET and Ewing sarcoma are pathologically distinct entities with very similar clinical and radiological characteristics. Immunohistochemical studies are needed to distinguish PNET from Ewing sarcoma, with the former being characterized by neural differentiation. We present the case of a 17-year-old man with immunohistochemically confirmed PNET in the cervical vertebrae.

[MR imaging appearances of schwannoma: correlation with pathological findings].

Peripheral schwannomas are nerve sheath neoplasms that consist of focal proliferation of Schwann cells. We reviewed the MRI findings in 17 patients with pathologically proved peripheral schwannomas. When compared with the signal intensity of muscle, that of the mass was isointense or hyperintense on T1-weighted images and hyperintense in all 17 tumors on T2-weighted images. All of the masses showed heterogeneous enhancement following the intravenous injection of Gd-DTPA on T1-weighted images. On T1-weighted images, hyperintensity was observed in the tumors that contained predominantly hypercellular Antoni type A tissue, while isointensity was observed in the tumors that contained predominantly hypocellular Antoni type B tissue. Relatively high signal intensity seen on T2-weighted images and Gd-DTPA enhanced T1-weighted images was observed in the tumors that contained predominantly Antoni type B tissue when compared with the signal intensity of tumors that contained predominantly Antoni type A tissue. A capsule was pathologically identified in 15 of 17 tumors. MRI correctly identified the presence of a capsule in 11 of 15 tumors and the absence of a capsule in one of 2 tumors. Thus the diagnostic accuracy was 71% (12/17). The cause of 4 false negative results appeared to be a hemorrhage or cystic change around the peripheral portion of the tumor, and it appeared to be a chemical artifact in one false positive result. Thus the appearance of MRI may suggest the cellular type of schwannoma, Antoni type A or B. However, prediction of the presence or absence of tumor capsule may be relatively difficult with MRI.

[US and CT findings of mucinous carcinomas of the gallbladder].

Mucinous carcinomas of the gallbladder are relatively uncommon. Their radiological findings have not been described previously. We describe the CT and US findings of mucinous carcinoma of the gallbladder in 3 cases. Tumors (thickened wall and/or intraluminal polypoid mass) showed hyperechogeneity or isoechogeneity on US and water density on CT. US clearly detected large polypoid lesions, but CT was unable to detect these lesions in 2 cases. Therefore, we stressed the discrepancy between the findings of US and CT. These features can be explained by the fact that a tumor containing a large amount of mucin produces a mass of near-water density in the gallbladder on CT. It is of value to know the radiological findings of these tumors because the diagnosis is easily missed by CT study alone.

[CT findings of pulmonary inflammatory pseudotumors (plasma cell granulomas)].

Pulmonary inflammatory pseudotumor (plasma cell granuloma) is not a true neoplastic lesion, but is composed of a variety of inflammatory cells, predominantly plasma cells. The chest X-ray features resemble those of malignant lung tumors; therefore, CT is often necessary for further evaluation. We report the CT features of five cases with histologically proved pulmonary inflammatory pseudotumor, which can be summarized as follows: a solitary round or oval parenchymal mass with regular or irregular margin, and with or without calcifications. The calcifications are useful for differential diagnosis if present, but they are usually non-specific in shape and configuration. The mean CT attenuation value of the major portion of the mass was increased from 41 HU to 78 HU by the injection of contrast material. In one case, a linear extension of the lesion was seen from the mass to the lung hilum. In three cases, satellite lung nodules were seen. One of these nodules was also proved histopathologically to be inflammatory pseudotumor. The biopsy specimens obtained by using a 20 gauge cutting-needle and an automated biopsy gun were satisfactory for histopathological diagnosis.