Nasopharyngeal undifferentiated carcinoma with sarcomatoid features: Pitfalls in the immunohistochemistry.

We present a case of an undifferentiated subtype of non-keratinizing squamous cell carcinoma (NK-SCC) with sarcomatoid features in the nasopharynx in a 69-year-old man who was difficult to diagnose due to spindle-shaped malignant cells. He was admitted because of a right nasal obstruction and right headache, and imaging revealed a heterogeneously enhanced irregularly shaped mass at the nasopharynx. Histopathologically, the tumour was partially organised, and the tumour cells were epithelioid or spindle-shaped. Initially, we erroneously diagnosed the tumour as an angiosarcoma owing to its false-negative immunoreaction for cytokeratins and a mistaken interpretation for CD31. After in situ hybridization for Epstein-Barr virus was positive, a consultation and additional immunostaining (including re-staining for cytokeratin with varying dilutions) were performed, and the diagnosis was revised to NK-SCC with sarcomatoid features. We believe that sarcomatoid features may be observed in nasopharyngeal carcinoma and in this case, immunostaining using various epithelial markers is necessary and careful attention should be paid to the interpretation of immunostaining.

Unrecognised IgG4 association in progressively transformed germinal centers of lymph nodes with subsequent full-blown IgG4-related chronic fibrosing pancreatitis: A case report.

Progressively transformed germinal centers (PTGC) is a benign process characterised by a morphological variant of reactive follicular hyperplasia in lymph nodes. It was recently shown that some cases of PTGC are associated with IgG4-related disease (IgG4-RD) or increased IgG4 plasma cells. Five years ago, a 57-year-old woman presented with enlargement of multiple lymph nodes in the left parotid, submandibular, and neck areas, pathologically diagnosed as PTGC after excisional biopsy. Since then, she has experienced numbness in her extremities, especially the left shoulder and arm, pruritus on the left side of the face and intermittent facial palsy, for which she has been receiving regular symptomatic treatment. Recently the patient developed diabetes mellitus (approximately seven months ago). In routine follow-up scans, a mass was detected in left kidney and magnetic resonance imaging of the abdomen prior to surgery revealed a slightly enhanced bulky mass replacing the pancreatic tail and uncinate process. The mass in left kidney was diagnosed as clear cell renal cell carcinoma, and the pathological features of the pancreatic lesion were those of IgG4-related chronic fibrosing pancreatitis. Retrograde examination of the neck lymph node diagnosed as PTGC showed increased deposition of IgG4-positive plasma cells.

Evaluation of In-Stent Restenosis After Stent Implantation in the Vertebral Artery Ostium by Multislice Computed Tomography Angiography: Factors Affecting Accurate Diagnosis.

PURPOSE: Few articles have evaluated vertebral artery ostium stents using multislice computed tomography (CT). The purpose of our study was to evaluate the diagnostic performance of 64- and 16-slice CT for detecting significant in-stent restenosis after vertebral artery ostium stenting, and to identify factors affecting the accurate diagnosis by CT. METHODS: We reviewed 57 stents scanned using 64-slice CT and 34 stents using 16-slice CT. The accuracy of CT for diagnosing significant in-stent restenosis (≥ 50% diameter narrowing) was calculated using conventional angiography as a reference standard. Possible factors influencing the diagnostic performance of CT were analyzed, such as CT scanner, image quality, and stent characteristics. RESULTS: With 64-slice CT, 46 (80.7%) of 57 stents were classified as evaluable, while with 16-slice CT, 28 (82.3%) of 34 stents were classified as evaluable. No stents with diameters ≤ 2.75 mm were evaluable. The respective results for 64- versus 16-slice CT were sensitivity 87.5% (95% confidence interval [CI] 47.3-99.7%) versus 100% (95% CI 15.8-100.0%), specificity 94.7% (95% CI 82.3%-99.4%) versus 96.2% (95% CI 80.4-99.9%). Factors reducing the accurate diagnosis were those associated with poor image quality, a diameter ≤ 2.75 mm, and drug-eluting stent type (p < 0.05). CONCLUSIONS: 64-slice and 16-slice CT scans are adequate in stents with diameters > 2.75 mm for the evaluation of in-stent restenosis after stent implantation in the vertebral artery ostium.

Spinal intradural extramedullary capillary hemangioma: MR imaging findings.

SUMMARY: Spinal intradural extramedullary capillary hemangiomas are extremely rare. We present the MR imaging and histologic findings in three patients with this abnormality. The three patients were men who had symptoms of either myelopathy (n = 2) or radiculopathy (n = 1). The tumors were well demarcated, 1.5-2.0 cm in diameter, and were located at the posterior or posterolateral portion of the thecal sac (one at the L1 level and the other two at the midthoracic level). On MR images, the tumor showed isointensity relative to the spinal cord on T1-weighted images, hyperintensity on T2-weighted images, and strong homogeneous enhancement on contrast-enhanced T1-weighted images in all three patients. In two patients, the dural tail sign was observed. Capillary hemangioma should be included in the differential diagnosis of a spinal intradural extramedullary tumor.

Comparative analysis of MR imaging, positron emission tomography, and ictal single-photon emission CT in patients with neocortical epilepsy.

BACKGROUND AND PURPOSE: MR imaging, positron emission tomography (PET), and single-photon emission CT (SPECT) play important roles in presurgical localization of epileptic foci. However, comparative study of these imaging methods for cases of neocortical epilepsy has been limited. The purpose of this study was to compare the sensitivities of these three imaging methods for presurgical localization of neocortical epileptogenic foci. METHODS: We studied 117 consecutive patients who underwent surgery for intractable neocortical epilepsy. The pathologic substrates were neuronal migration disorder (n = 77), tumor (n = 15), and others (n = 25). MR imaging was compared retrospectively with (18)F-fluorodeoxyglucose PET and ictal technetium-99m hexamethylpropyleneamine oxime SPECT regarding their capability to correctly localize the epileptogenic foci. The pathologic findings were used as the standard of reference. RESULTS: Overall, MR imaging, PET, and ictal SPECT correctly localized the lesions for 59.8%, 77.7%, and 70.3% of the patients, respectively, with a 38% concordance rate among the three methods. PET was most sensitive (71-100%) in detecting all substrates. MR imaging was as sensitive (100%) as PET in detecting tumor but was least sensitive (48.1%) in detecting neuronal migration disorder. Ictal SPECT was more sensitive (75.8%) than MR imaging in detecting neuronal migration disorder. Patients with imaging abnormalities achieved good outcomes in 81.4% of the cases, in contrast to 59.5% for those without imaging abnormalities (P <.05). CONCLUSION: PET and ictal SPECT were overall more sensitive than was MR imaging, despite the low concordance rate and variable sensitivity depending on substrates. The detection of abnormalities by MR imaging was associated with good outcome. PET or ictal SPECT can be well used as complementary tools, particularly in cases of negative MR imaging findings.

Lateralizing ability of single-voxel proton mr spectroscopy in hippocampal sclerosis: comparison with mr imaging and positron emission tomography.

BACKGROUND AND PURPOSE: Proton MR spectroscopy (MRS) is still in the early stages in the evaluation of epilepsy, and comparisons with MR imaging and positron emission tomography (PET) in the same patients have rarely been documented. The purpose of this study was to evaluate the lateralizing ability of single-voxel MRS in comparison with MR imaging and PET in patients with hippocampal sclerosis. METHODS: Thirty-three patients with intractable temporal lobe epilepsy whose MR imaging diagnosis was unilateral hippocampal sclerosis and who underwent anterior temporal lobectomy and had good postsurgical outcome over 1-year follow-up were included in the study. MR spectra were obtained from the hippocampus bilaterally, using the point-resolved spectroscopy sequence. Metabolite ratios of NAA/Cho and NAA/Cr were calculated from the relative peak height measurements. An NAA/Cho ratio of 0.8 or less and an NAA/Cr ratio of 1.0 or less were regarded as abnormal. The MRS results were compared retrospectively with those of MR imaging and PET as to the ability to lateralize the epileptogenic focus. RESULTS: The sensitivity of MRS and PET (concordance with MR imaging) was 85% each in the lateralization of the ipsilateral lesion side. Bilateral abnormalities were seen in 30% of the patients. False-lateralization rates for MRS and PET were 3% and 6%, respectively. The concordance rate of MRS and PET was 73%, when comparing the results of the ipsilateral lesion side. CONCLUSION: MRS may be used as an adjunct tool in the evaluation of hippocampal sclerosis, like PET, although its sensitivity has to be improved and the clinical significance of bilateral abnormality is still to be determined.

Usefulness of single voxel proton MR spectroscopy in the evaluation of hippocampal sclerosis.

OBJECTIVE: The purpose of our study was to determine the ability of H-1 MR spectroscopy (MRS) to lateralize the lesion in patients with hippocampal sclerosis. MATERIALS AND METHODS: Twenty healthy volunteers and 25 patients with intractable temporal lobe epilepsy whose MR imaging diagnosis was unilateral hippocampal sclerosis were included. This diagnosis was based on the presence of unilateral atrophy and/or high T2 signal intensity of the hippocampus. Singlevoxel H-1 MRS was carried out on a 1.5-T unit using PRESS sequence (TE, 136 msec). Spectra were obtained from hippocampal areas bilaterally with volumes of interest (VOIs) of 6.0 cm(3) and 2.25 cm(3) in healthy volunteers, and of either 6.0 cm(3) (n = 14) or 2.25 cm(3) (n = 11) in patients. Metabolite ratios of NAA/Cho and NAA/Cr were calculated from relative peak height measurements. The capability of MRS to lateralize the lesion and to detect bilateral abnormalities was compared with MR imaging diagnosis as a standard of reference. RESULTS: In healthy volunteers, NAA/Cho and NAA/Cr ratios were greater than 0.8 and 1.0, respectively. In patients, the mean values of these ratios were significantly lower on the lesion side than on the contralateral side, and lower than those of healthy volunteers (p <.05). The overall correct lateralization rate of MRS was 72% (18/25); this rate was lower with a VOI of 6.0 cm(3) than of 2.25 cm(3) (64% versus 82%, p <.05). Bilateral abnormalities on MRS were found in 24% (6/25) of cases. CONCLUSION: Although its rate of correct lateralization is low, single-voxel H-1 MRS is a useful and promising diagnostic tool in the evaluation of hippocampal sclerosis, particularly for the detection of bilateral abnormalities. To improve the diagnostic accuracy of H-1 MRS, further investigation, including the use of a smaller VOI and measurement of the absolute amount of metabolites, are needed.

Hippocampal sclerosis: correlation of MR imaging findings with surgical outcome.

OBJECTIVE: Atrophy and a high T2 signal of the hippocampus are known to be the principal MR imaging findings of hippocampal sclerosis. The purpose of this study was to determine whether or not individual MRI findings correlate with surgical outcome in patients with this condition. MATERIALS AND METHODS: Preoperative MR imaging findings in 57 consecutive patients with pathologically-proven hippocampal sclerosis who underwent anterior temporal lobectomy and were followed-up for 24 months or more were retrospectively reviewed, and the results were compared with the postsurgical outcome (Engel classification). The MR images included routine sagittal T1-weighted and axial T2-weighted spin-echo images, and oblique coronal T1-weighted 3D gradient-echo and T2-weighted 2D fast spin-echo images obtained on either a 1.5 T or 1.0 T unit. The images were visually evaluated by two neuroradiologists blinded to the outcome; their focus was the presence or absence of atrophy and a high T2 hippocampal signal. RESULTS: Hippocampal atrophy was seen in 96% of cases (55/57) [100% (53/53) of the good outcome group (Engel class I and II), and 50% (2/4) of the poor outcome group (class III and IV)]. A high T2 hippocampal signal was seen in 61% of cases (35/57) [62% (33/53) of the good outcome group and 50% (2/4) of the poor outcome group]. All 35 patients with a high T2 signal had hippocampal atrophy. 'Normal' hippocampus, as revealed by MR imaging, occurred in 4% of patients (2/57), both of whom showed a poor outcome (Engel class III). The presence or absence of hippocampal atrophy correlated well with surgical outcome (p<0.01). High T2 signal intensity did not, however, significantly correlate with surgical outcome (p>0.05). CONCLUSION: Compared with a high T2 hippocampal signal, hippocampal atrophy is more common and correlates better with surgical outcome. For the prediction of this, it thus appears to be the more useful indicator.

Diffusion MR imaging of hypoglycemic encephalopathy.

BACKGROUND AND PURPOSE: MR imaging features of HE have not been fully established. The purpose of this study was to determine the topographic distribution and DWI findings of HE. MATERIALS AND METHODS: We retrospectively evaluated HE MR imaging (n = 11). The topographic distribution of the lesions was evaluated on routine MR imaging, and DWI SI and ADC values were assessed. The ADC value of involved lesions was compared with the noninvolved subcortical WM area by use of the paired t test. RESULTS: MR images demonstrated bilateral diffusion-restrictive lesions in the posterior limb of the IC (n = 6), cerebral cortex (n = 8), CR (n = 7), CS (n = 9), hippocampus (n = 4), and BG (n = 1). The mean ADC value of lesions was 448.82 +/- 92.34 x 10(-6) mm(2)/s compared with the mean ADC value of noninvolved lesions (837.72 +/- 62.14 x 10(-6) mm(2)/s); this difference was statistically significant (P < .000). The lesions showed complete resolution on follow-up DWI for 6 patients. Three patients with cortical involvement of > or = 2 lobes showed partial recovery or death, but most of the other patients with WM involvement or cortical involvement in only 1 lobe experienced complete recovery. CONCLUSIONS: The topographic localization of the lesions was the posterior limb of the IC, cerebral cortex, CR, CS, hippocampus, and BG. Most HE lesions probably correspond to areas of reversible cytotoxic edema as seen on DWI, which can predict the prognosis of HE according to the degree of lesion extent.

Cellular senescence, radiation damage to mitochondria, and the compensatory response in ripening pear fruits.

A compensatory response, viz. in vivo recovery from radiation damage to mitochondria, occurs in preclimacteric pear fruits (Pyrus communis L.) treated with ionizing radiation. The compensatory response is absent or markedly impaired in senescent fruits irradiated at or near the climacteric peak. Senescent cells failed to recover from harmful effects of radiation on: 1) mitochondrial yield, 2) in vivo incorporation of amino acids into mitochondrial protein, and 3) mitochondrial respiratory control and ADP/O. A diminished response to "split-dose" irradiation and a delayed rate of recovery confirmed the degeneracy and loss of compensatory power with cell age.A loss of restorative activity, especially in mitochondria that supply the cell with essential energy, may underlie the more obvious signs of cumulative stress that accompany cellular senescence. Use of ionizing radiation as an investigative tool and the molecular implications of radiation damage, recovery, and cellular senescence are discussed.

MRI features of choroid plexitis.

Four cases of choroid plexitis of the brain (two with cryptococcosis and two with tuberculosis) are presented. The four patients showed either unilateral enlargement (3) or bilateral enlargement (1) and dense enhancement of the choroid plexus in the lateral ventricles (4) and fourth ventricle (1) in association with clinical findings of leptomeningitis. All patients had unilateral cystic dilatation of the temporal horn of the lateral ventricle presumably secondary to entrapment of the temporal horn and extensive oedema around the ipsilateral ventricle.

Mediastinal tuberculous lymphadenitis: MR imaging appearance with clinicopathologic correlation.

OBJECTIVE: The purpose of our study was to determine the MR imaging appearance of mediastinal tuberculous lymphadenitis and to compare these findings with clinical and pathologic findings. MATERIALS AND METHODS: MR images of 23 consecutive patients with mediastinal tuberculous lymphadenitis were retrospectively analyzed with regard to homogeneity, signal intensity, and enhancement of diseased nodes after injection of contrast material (n = 19), and the imaging findings were grouped by patterns and correlated with clinical signs or symptoms and with pathologic (n = 9) findings. RESULTS: Three imaging patterns of mediastinal tuberculous lymphadenitis (113 nodes) were seen of MR images. In six patients, nodes (type 1, n = 25) were relatively homogeneous and hyperintense to muscle on both T1- and T2-weighted images and enhanced homogeneously after injection of contrast material. The patients had mild (n = 2) or no (n = 4) constitutional symptoms. The nodes corresponded pathologically to tuberculous granulomas without or with minimal necrosis. In 14 patients, nodes (type 2, n = 71) were inhomogeneous with a strong peripheral enhancement after injection of contrast material. Enhancing areas were of intermediate intensity on T1-weighted images and hypointense on T2-weighted images, and corresponded pathologically to peripheral granulation tissue within the nodes. Unenhanced areas were relatively hypointense on T1-weighted images and markedly hyperintense on T2-weighted images, and corresponded pathologically to central caseation or liquefaction necrosis within the nodes. All but one patient with type 2 nodes had moderate to severe clinical signs and symptoms. In the remaining three patients, nodes (type 3, n = 17) were homogeneously hypointense on both T1- and T2-weighted images and did not enhance after injection of contrast material. No patient with type 3 nodes had clinical signs or symptoms. The nodes corresponded pathologically to fibrocalcified nodes. CONCLUSION: The most common MR imaging appearance of mediastinal tuberculous lymphadenitis was as inhomogeneous nodes with marked hyperintensity on T2-weighted images and peripheral enhancement after injection of contrast material. This typical MR imaging appearance was mostly seen in severely symptomatic patients and was due to caseation necrosis of the tuberculous nodes.

Undifferentiated embryonal sarcoma of the liver: US and CT findings.

Six cases of undifferentiated embryonal sarcoma (UES) were reviewed to determine their characteristic features on ultrasonography (US) (n = 5) and computed tomography (CT) (n = 6). US demonstrated a single large, echogenic mass with some anechoic spaces. Contrast-enhanced CT scan revealed a well-demarcated low-attenuation mass with hyperdense septations of variable shape and thickness. Discrepancy of internal architecture on US and CT was one of the important characteristics of UES. CT numbers were 25-47 HU in low-attenuation areas. Enhancing peripheral rim was found in four cases and some solid portions at the periphery or adjacent to the septa were found in all cases. Two patients who had follow-up US and CT without treatment showed enhancing solid portions, changing to hypodense as the tumor grew. When compared with the pathologic findings, US showed a more accurate representation of internal architecture than did CT. Familiarity with these US and CT findings of UES of the liver will be helpful in the differential diagnosis of primary hepatic tumors in childhood.