Myoepithelioma and malignant myoepithelioma arising from the salivary gland: computed tomography and magnetic resonance findings.

We report the CT and MRI appearance of myoepithelioma and malignant myoepithelioma arising from accessory salivary glands of the soft palate and the submandibular gland. Correlation of the imaging features and histologic finding is presented. Radiologists should bear in mind that myoepithelioma and malignant myoepithelioma are included in radiological differential diagnosis of head and neck tumours.

MR imaging of synovial sarcoma arising from the floor of the mouth: a case report.

A previously unreported synovial sarcoma arising from the floor of the mouth occurred in a 46-year-old man. Preoperative MR imaging findings of the tumor reflected the macroscopic findings of the resected mass. MR imaging findings were helpful in the diagnosis of this malignancy.

[MALT-type lymphoma of the lacrimal gland: a case report].

We report a rare case of MALT-type lymphoma of the lacrimal gland in a 29-year-old woman. CT scan demonstrated a solid homogenous mass in the right lacrimal gland fossa and the palpebral lobe of the lacrimal gland with contrast enhancement. The mass displayed slight hyperintensity on T1-weighted images and hyperintensity on T2-weighted images with fat saturation. The mass demonstrated an arc-like contour, and involved both the palpebral lobe and orbital lobe of the lacrimal gland. These characteristic findings may be helpful in the diagnosis of this malignancy.

[Natural history of intracranial meningioma after radiotherapy].

The author examined the natural history of intracranial meningioma after radiotherapy using CT or MR imaging. Twenty patients with intracranial meningioma received radiotherapy from a high-energy linear accelerator (4-10 MV X rays) from 1980 to 1996. The total doses were 50 Gy to the tumor bed in single doses of 2 Gy in 5 weekly fractions. Meningiomas in 10 of 20 patients were reduced within 1 to 38 months after radiotherapy, the average being 11 months. The tumors were controlled for a median of 60 months after radiotherapy (range 19-126 months). Four other patients have shown no change in tumor size after radiotherapy. The tumors were controlled for a median of 70 months after radiotherapy (range 37-127 months). The other six patients have shown tumor growth within 3 to 25 months after radiotherapy, after which the tumors stopped growing for a median of 71 months (range 2-181 months). Neither tumor size nor histological type was related to response. The growth of tumors was controlled by radiotherapy for a median duration of 43 months in the meningothelial type, 52 months in the fibroblastic type, and 61 months in the transitional type. The median duration for all benign tumors was 52 months. A moderate correlation was noted between tumor response and functional outcome after radiotherapy in 9 patients with neurological deficits. The natural histories of intracranial meningiomas after radiotherapy were grouped into three categories. Some tumors showed no change in size over a long period. This was a characteristic response after radiotherapy that differed from that of other brain tumors. The results of this study provide important information for the follow-up of intracranial meningiomas after radiotherapy.

[Delineation of the white and gray matter of the normal human cervical spinal cord using diffusion-weighted echo planar imaging].

To delineate the white and gray matter of the normal human cervical spinal cord, diffusion-weighted echo planar imaging (DW-EPI) was performed in 11 healthy volunteers. Three axial (X-, Y- and Z-axis) anisotrophic diffusion-weighted images were obtained on a 1.5T superconducting clinical unit using a single-shot DW-EPI sequence. On X- and Y-axis DWIs the white and gray matter could be well differentiated: the former showed high intensity and the latter low intensity. Anterior columns were clearly visible, whereas posterior columns were not. On Z-axis DWI the white and gray matter could not be differentiated at all, because both showed low intensity. In conclusion, DW-EPI can clearly delineate the white and gray matter of the cervical spinal cord, and this technique will be useful to evaluate white matter disorders such as ischemic or demyelinating disease.

[Delineation of calf deep veins using 2D-TOF MR venography without contrast media: efficacy of tourniquet and leg-warming].

We evaluated the imaging quality of 2D-TOF MR venography of the lower part of the leg and the efficacy of a tourniquet around the knee and leg-warming. In 8 healthy volunteers, MR venography was carried out under the following four conditions: (a) usual MR venography, (b) MR venography with tourniquet around the knee, (c) MR venography after leg-warming and (d) MR venography with tourniquet after leg-warming. Our results suggested that MR venography with tourniquet after leg-warming is best suited for imaging the veins of the leg. We also compared the diagnostic image quality of MR venography and conventional contrast venography in 7 patients with varices. The results showed no significant differences between the two methods. We conclude that MR venography with tourniquet after leg-warming is a technique that provides reliable information about the veins of the leg.

[The usefulness of radiotherapy in the management of intracranial meningioma: a review of 29 patients].

Twenty-nine patients with intracranial meningiomas were treated with a high-energy linear accelerator (4-10 MV. X rays and electron beams) between 1980 and 1992 at the Hiroshima Prefectural Hiroshima Hospital. We investigated the relationships between tumor size and tumor response, histological type and tumor response, and grade of operation using Simpson's classification and recurrence rate. Meningiomas were greatly reduced between 1 month and 46 months after radiotherapy, the average being 14 months. In the group with a tumor size of less than 5 cm2, 3 patients obtained CR, 5 patients NC and 1 patient PD. Tumor response was 89% in the group with a combination of CR with NC. In the group with a tumor size of 5 to 20 cm2, 2 patients obtained PR, 1 patient NC and 1 patient PD. Tumor response was 75% in the group with a combination of PR with NC. In the group with a tumor size of more than 20 cm2, 3 patients showed NC, 3 patients PD. Tumor response was 50% in the group with NC. In the group with a tumor size of less than 20 cm2, tumor response was 85%. In the group with a tumor size of more than 20 cm2, it was 50%. Though there were no statistically significant differences between the two groups, a tumor size of less than 20 cm2 had a tendency to be more responsive than one of more than 20 cm2. The response of meningioma of the transitional type was worse than that of the meningothelial type and fibroblastic type. Fourteen patients after Simpson grade II or III operation were free of recurrence. The results of this study support the role of radiotherapy for meningioma which is less than 20 cm2, and also for treatment after Simpson grade II or III operation.

[Uterine cervical cancer: usefulness of MR imaging after the initial radiation therapy].

To evaluate the usefulness of magnetic resonance imaging (MRI) in diagnosing residual or recurrent tumors of cervical cancer after radiation therapy, we investigated the time difference between MRI and gynecologic findings in the diagnosis of residual or recurrent tumor in 12 patients with invasive cervical cancer. We defined a positive finding for residual or recurrent tumor as an uterine cervical mass isointense to muscle on T1-weighted images and hyperintense on T2-weighted images, and when a positive biopsy specimen was obtained. Two patients were diagnosed as having a residual or recurrent tumor by MRI. Positivity was demonstrated four and seven months later, respectively. MRI was more useful in the earlier diagnosis of residual or recurrent tumor of cervical cancer after radiation therapy than uterine biopsy. There was one patient whose differentiation from residual tumor or radiation-induced necrosis or inflammation on MRI was difficult. MRI and gynecologic check-up at a regular interval after radiation therapy was needed to distinguish them. One patient was diagnosed as having a recurrent tumor by gynecologic finding three month earlier than by MRI. Follow-up MRI examinations at a regular interval in addition to gynecologic examination is necessary for the early detection of recurrent cervical cancer after radiation therapy.

Intraarterial infusion of cisplatin with and without preoperative concurrent radiation for urinary bladder cancer: a preliminary report.

We evaluated the clinical efficacy of treating urinary bladder cancer by intraarterial infusion of cisplatin using an implanted reservoir with and without preoperative concurrent radiation. No previous reports have compared the results obtained by these two methods of treatment. Twenty-three patients with bladder cancer were treated by intraarterial infusion of cisplatin using an implanted reservoir with (n = 13) and without (n = 10) concurrent radiation. The cisplatin plus radiation group received intraarterial cisplatin at a total dose of 200-400 mg and concurrent radiation to a total dose to 30 Gy. The cisplatin group received intraarterial cisplatin at a total dose of 100-600 mg. In the cisplatin plus radiation group, the overall tumor response rate was 92%. Seven of 13 (53%) patients obtained complete response (CR), and the 2-year actuarial survival rate was 92%. Only one of the seven complete responders has had a local recurrence. In the cisplatin group, the overall tumor response rate was 90%. Four of 10 (40%) patients obtained CR, and median survival was 8 months. Three of the four complete responders have had local recurrence. There was no significant difference between these two groups in the frequency of side effects. Concurrent radiation therapy with intraarterial cisplatin resulted in a very low rate of recurrence of bladder cancer compared with intraarterial cisplatin therapy alone. This method was useful for urinary bladder cancer and may become the treatment of choice for this type of cancer.

[An afterloading procedure using 137Cs needle for tongue carcinoma].

We have developed an afterloading procedure using Cs needle for tongue carcinoma. Seven patients with T1-2NO squamous cell carcinoma of the oral tongue were treated by this method at the Oita Medical University between 1988 and 1994. This method reduced the radiotherapist's radiation exposure and resulted in good local control in the primary site. We have found no other report of a case treated in this way. We emphasize that cesium therapy using an afterloading procedure is very useful in treating tongue carcinoma.

Sebaceous carcinoma responds to radiation therapy.

We describe a patient with an eyelid tumor that responded well to radiation therapy. The histopathological diagnosis was poorly differentiated sebaceous carcinoma. The patient received 52 Gy electron beam irradiation in a 5-week period; thereafter, the tumor diminished. The histopathological findings after radiation showed that most tumor cells underwent massive necrosis with hyalinized obstructive vessels. The tumor was under control at the 9-month follow-up examination.

[CT findings of pulmonary paragonimiasis westermani].

The CT findings of six patients (three symptomatic and three asymptomatic) with pulmonary paragonimiasis westermani were reviewed in correlation with the findings of radiography. Pleural changes were recognized in all cases on CT. In addition to pleural fluid collection and hydropneumothorax, which were demonstrated on plain radiograph, CT showed minimal pleural thickening and adhesion adjacent to the parenchymal lesions. CT showed round nodules of lower attenuation within a subpleural consolidation of triangular shape in two patients. Small air-filled cavities in a parenchymal lesion with central dense spots were demonstrated in two patients, and multiple cavities with irregular wall were seen in one patient. CT also demonstrated the parenchymal lesion with a tunnel-like cavity in one patient. These may represent the worm nodules, the worm within worm cysts, and the worm migration tract, respectively. These pulmonary lesions were located adjacent to the localized pleural thickening or adhesion in all six cases. CT was more useful than radiography in the diagnosis of pulmonary paragonimiasis westermani.

Hydronephrosis caused by a left renal vein in a patient with horseshoe kidney: a case report.

We report a rare case of hydronephrosis secondary to ureteropelvic stenosis caused by a branch of the left renal vein in horseshoe kidney. We were unable to determine the etiology of hydronephrosis of the horseshoe kidney by means of radiological images. When radiological images fail to show any etiology of hydronephrosis in horseshoe kidney, the possibility of compression of the ureteropelvic junction by a branch of the renal vein should be borne in mind, and re-assessment of the venous phase of angiography and evaluation by coronal or sagittal images of MRI is recommended.

[The effectiveness of radiotherapy for Merkel cell carcinoma].

Merkel cell carcinoma is a high-grade malignant tumor of the skin that tends to extend locally and metastasize to regional lymph nodes. Surgical resection is the treatment of choice, and the effectiveness of radiotherapy for this disease has not yet been established. We report two cases of biopsy-proven Merkel cell carcinoma effectively treated with radiotherapy. Histopathological examination of the resected specimens after radiotherapy of 50 Gy and 38 Gy, respectively, using 6 approximately 15 MeV electrons showed no malignant cells in either case. No evidence of recurrence or metastasis has been noted in 11 to 21 months after radiotherapy. To our knowledge, no case of Merkel cell carcinoma in which complete cure was obtained by radiotherapy alone has been reported previously. It is considered that preoperative radiotherapy would contribute to the management of this locally invasive but radiosensitive tumor.

Dilated posterior superior pancreaticoduodenal vein: recognition with CT and clinical significance in patients with pancreaticobiliary carcinomas.

The authors retrospectively reviewed computed tomographic (CT) scans, angiograms, and surgical-pathologic records of 226 patients without and 64 patients with pathologically proved pancreaticobiliary carcinoma to evaluate frequency of depiction, normal range of size, and causes of dilatation of the posterior superior pancreaticoduodenal vein (PSPDV) at CT. Among the patients with pancreaticobiliary carcinoma, CT demonstrated enlarged PSPDVs (diameter, greater than or equal to 8 mm) in seven patients. CT and angiography showed that the portal-superior mesenteric vein (P-SMV) was occluded or stenotic at its confluence in three patients and was normal in four patients. Among the latter four patients, localized tumor invasion was found surgically-pathologically along the right lateral wall of the P-SMV in three. A dilated PSPDV with obliteration of the P-SMV at CT may confirm tumor extension to the P-SMV. In patients with a normal P-SMV at CT, a dilated PSPDV indicates that the tumor has extended beyond the pancreatic parenchyman and occluded other pancreaticoduodenal veins or extended to the wall of the P-SMV.

[Intracranial accumulation of 99mTc-phosphorous compound on bone scintigraphy].

Bone scintigrams of 99mTc-phosphorous compound in 4,579 cases were reviewed concerning the intracranial accumulation. Intracranial accumulations were demonstrated in 8 cases (0.17%). The lesions with intracranial accumulation were two cases of primary brain tumor (1 meningioma and 1 astrocytoma), five cases of metastatic brain tumor (1 rectal cancer, 1 gastric cancer, 1 uterine cervical cancer and 2 lung cancers) and one case of cerebral infarction. Calcification was detected in one of eight cases on CT scans. It is important to pay attention to the intracranial accumulation on routine bone scintigram because brain tumor or infarction may be detected.

[Ultrasonography and CT of thyroglossal duct cysts].

A retrospective analysis of pathologically proved 7 cases of thyroglossal duct cysts was performed in an attempt to determine the characteristics of these lesions using both ultrasonography (US) and computed tomography (CT). US showed cystic mass with variable internal echoes or debris in 6 of 7 cases and internal septation in two. CT showed hypodense mass in all 4 cases of which attenuation value were higher than that of water, and rim-enhancement of the wall in one case. CT and US also showed calcification of the wall in one patient. To our knowledge, calcification of the wall of thyroglossal duct cyst was not reported previously. These findings described above may be due to complicated inflammation, and may enable to differentiate the thyroglossal duct cyst from the other neck masses.

[CT and sonographic diagnosis of retained surgical sponge].

Seven cases of pathologically proven retained surgical sponge were reviewed and classified into four types, depending on CT and US findings. Type I: CT shows a mass with tiny gas bubbles, and sonogram shows an echogenic area with strong posterior shadow. Type II: CT shows an irregular high density mass with no gas bubble, and sonogram shows an echogenic area with strong posterior shadow. Type III: CT shows a low density mass with irregular internal high density areas, and sonogram shows a cystic mass with zigzag internal components. Type IV: CT shows an elliptic high density mass with low density area internally. Judging from the experiment and operative findings, these patterns were decided by the number and status of the gauze, volume of the exudate and hematoma, and status of the granulation. The author concludes that these characteristic CT and US findings, together with a history of surgery, permit the correct diagnosis of retained surgical sponge.

[Sclerotic changes in bone tumors following radiation therapy].

54 cases of osteolytic bone tumors were investigated concerning sclerotic change after radiotherapy. Particular attention was paid to the frequency and the appearance time of sclerotic change, and also to the effects of sclerotic change on pathological fracture and prognosis. There was no correlation between the sclerotic change and the frequency of pathological fracture. However, the interval between radiotherapy and pathological fracture tended to be longer in the group with sclerotic change. Sclerotic change after radiotherapy is considered as a sign of good therapeutic local effect and better prognosis.

[Radiosensitivity of soft tissue sarcomas].

The correlation between the effectiveness of radiation therapy and the histology of soft tissue sarcomas was investigated. Of 31 cases with a soft tissue sarcoma of an extremity treated by conservative surgery and postoperative radiation of 3,000-6,000 cGy, local recurrence occurred in 12; 5 out of 7 synovial sarcomas, 4 of 9 MFH, one of 8 liposarcomas, none of 4 rhabdomyosarcomas and 2 of 3 others. As for the histological subtyping, the 31 soft tissue sarcomas were divided into spindle cell, pleomorphic cell, myxoid and round cell type, and recurrence rates were 75%, 33.3%, 16.7% and 0%, respectively. From the remarkable difference in recurrence rate, it was suggested that round cell and myxoid type of soft tissue sarcomas showed a high radiosensitivity compared to the spindle cell type with low sensitivity. Clarifying the degree of radiosensitivity is helpful in deciding on the management of limb salvage in soft tissue sarcomas of an extremity.