Extramedullary hematopoiesis encasing the pelvicalyceal system: CT findings

A rare case of symmetric renal extramedullary hematopoiesis is hypothesized in a patient with longstanding Vaquez' disease and myelofibrosis. At CT, soft tissue densities were found in the renal hilar area encasing the pelvicalyceal system. Although there is nothing specific about the CT findings, the diagnosis can be suggested in the proper clinical setting. The association with generalized osteosclerosis is another diagnostic clue.     

CT of nasopharyngeal carcinoma: significance of widening of the preoccipital soft tissue on axial scans

Axial CT scans of 60 patients with biopsy-proved nasopharyngeal carcinoma were reviewed with particular reference to sites of origin and routes of spread of disease. In all patients there was involvement of the pharyngeal space with blunting of the fossa of Rosenmuller and usually associated thickening of the adjacent levator veli palatini muscle. Tumor infiltration through the pharyngobasilar fascia manifested by obliteration or displacement of the parapharyngeal fat space was seen in 65% of the patients. T-staging by CT showed T1 (28%), T2 (20%), T3 (5%), and T4 (47%) involvement. In three patients there was bilateral symmetric blunting of the fossa of Rosenmuller with no evidence of tumor infiltration into the parapharyngeal space. The scans were initially interpreted as normal except for widening of the preoccipital soft-tissue area in the midline of more than 1.5 cm and up to 2.0 cm in the anteroposterior plane. Biopsy of the postnasal space was positive for tumor in these patients. With symmetric, early stage nasopharyngeal carcinoma, a confident radiologic diagnosis on CT can be difficult. If there is asymmetry of pharyngeal mucosal space or evidence of deep infiltration this should not be a problem. Although lymphoid adenoid tissue can sometimes result in widening of the preoccipital area, it is proposed that widening of this area of greater than 1.5 cm is an additional CT sign of nasopharyngeal carcinoma not previously emphasized. It is the result of early submucosal infiltration of the disease, and a patient with clinically suspected nasopharyngeal carcinoma should have aggressive deep biopsies of the fossa of Rosenmuller.     

Penetrating keratoplasty for bilateral acute corneal calcification.

A 76-year-old man with bilateral practolol-induced dry eyes developed atypical acute bilateral corneal calcification. Serum calcium, phosphate, and urea levels were within normal limits. The calcium deposition progressed rapidly to involve 90% of the right cornea. Right penetrating keratoplasty was performed with subsequent visual rehabilitation of the patient. Left tectonic penetrating keratoplasty was performed 8 weeks later after corneal perforation. The corneal specimens were examined by light and electron microscopy, which showed an atypical calcareous degeneration involving Bowman's layer as well as the full thickness of the stroma. Transmission electron microscopy showed the granular calcification to consist of extracellular, radially orientated aggregates of fine, needle-shaped crystals. Both transplants remained clear with no evidence of postoperative recurrence. To our knowledge this is the first report of bilateral penetrating keratoplasty for acute calcareous degeneration.     

Spiral CT of intracranial aneurysms: Correlation with digital subtraction and magnetic resonance angiography

Spiral CT and magnetic resonance angiography (MRA) were performed in ten patients with 14 intracranial aneurysms known from conventional angiography. All lesions, the smallest 3 mm in diameter, were visible on spiral CT and MRA. The neck of the aneurysm and its anatomical relations could very accurately be determined in all cases. Advantages of spiral CT over MRA are: a short acquisition time with reduction of motion artefacts, no dependence on flow rate or cardiac output, and excellent visualisation of calcification, thrombus and bony landmarks. Disadvantages are the necessity for iodinated contrast medium, long postprocessing and reconstruction time and the possibility of overlap of bone and venous blood.     

Solitary true cyst of the pancreas

We report a case of a woman diagnosed with a solitary true cyst of the pancreas. CT and especially MRI guided us in the diagnosis of this benign lesion. The cyst has been surgically removed because of secondary bile-duct obstruction causing painless jaundice. Clinical history, laboratory, imaging, and histological findings are reported. Received 28 May 1997; Revision received 21 December 1997; Accepted 24 December 1997     

Metastasis of transitional cell carcinoma to the lower abdominal wall 20 years after cystectomy

Iatrogenic implantation has been the main cause in the majority of cases of transitional call carcinoma (TCC) with metastasis to the abdominal wall. A 66-year-old woman had undergone radical cystectomy 20 years prior to presenting. Radiological investigations revealed one mass in the left lower abdominal wall and one mass in the right inguinal area. She underwent wide excision of the lesions that revealed metastasis of TCC. This report describes this case of a woman with bladder carcinoma who developed a metastasis in the anterior abdominal wall following an apparent disease-free interval of 20 years.     

NKT cells promote antibody-induced joint inflammation by suppressing transforming growth factor beta1 production

Although NKT cells has been known to exert protective roles in the development of autoimmune diseases, the functional roles of NKT cells in the downstream events of antibody-induced joint inflammation remain unknown. Thus, we explored the functional roles of NKT cells in antibody-induced arthritis using the K/BxN serum transfer model. NKT cell-deficient mice were resistant to the development of arthritis, and wild-type mice administrated with alpha-galactosyl ceramide, a potent NKT cell activator, aggravated arthritis. In CD1d-/- mice, transforming growth factor (TGF)-beta1 was found to be elevated in joint tissues, and the blockade of TGF-beta1 using neutralizing monoclonal antibodies restored arthritis. The administration of recombinant TGF-beta1 into C57BL/6 mice reduced joint inflammation. Moreover, the adoptive transfer of NKT cells into CD1d-/- mice restored arthritis and reduced TGF-beta1 production. In vitro assay demonstrated that interleukin (IL)-4 and interferon (IFN)-gamma were involved in suppressing TGF-beta1 production in joint cells. The adoptive transfer of NKT cells from IL-4-/- or IFN-gamma-/- mice did not reverse arthritis and TGF-beta1 production in CD1d-/- mice. In conclusion, NKT cells producing IL-4 and IFN-gamma play a role in immune complex-induced joint inflammation by regulating TGF-beta1.     

T cell expression of CIITA represses Th1 immunity

Despite the fact that major histocompatibility complex class II transactivator (CIITA) has been known to be involved in Th1/Th2 balance in addition to its major role as a master regulator for the expression of MHC class II genes, the exact role of CIITA in Th1/Th2 balance is still controversial. To investigate whether the Th1/Th2 balance could be modulated by T cell specific expression of CIITA, we generated CIITA-transgenic mice, in which the CIITA expression is controlled by the distal promoter of p56lck, resulting in constitutive expression of CIITA predominantly in peripheral T cells. Naive CD4+ T cells from CIITA-transgenic mice exhibited a low level of IFN-gamma secretion as well as impaired Th1 polarization in vitro, while IL-4 secretion was enhanced under Th2 condition. In addition, the development of experimental autoimmune encephalomyelitis (EAE), a prototype of Th1-mediated disease, was repressed in CIITA-transgenic mice. Resistance to EAE was correlated with reduced production of IFN-gamma in response to MOG35-55, while the proliferation of MOG35-55 -specific T cells was not affected in CIITA-transgenic mice. Together, these data demonstrate that overexpression of CIITA in T cells inhibits Th1 differentiation and function, suggesting that the expression of CIITA in T cells might play a role in the regulation of the Th1/Th2 balance during the T cell lineage commitment.