Ko Matsumoto

MR imaging of multiple sclerosis simulating brain tumor

Multiple sclerosis may sometimes present as a mass lesion that is indistinguishable from brain tumor both clinically and radiologically. We describe two cases of multiple sclerosis simulating brain tumor on computed tomography (CT) scans and magnetic resonance (MR) images, one of which was proved and another was suggestive to be demyelinating disease by biopsy. Steroid therapy produced regression of the lesions of MR images and CT scans. Our cases and others in the literature suggest strategies for detecting multiple sclerosis presenting as a mass lesion.

Prognostic analysis of malignant pleural and peritoneal effusions

A total of 289 cases with malignant pleuroperitoneal effusions were reviewed, and their prognosis were analyzed in relation to the following factors: (1) chronologically divided series; (2) previous tumorectomy of the primary lesion; (3) presence or absence of other metastases; (4) site of effusion; (5) site of the primary lesion; (6) cytologic characteristics of effusion. Prognostic difference among each chronologically divided series was not noticed. Previous tumorectomy slightly improved the patients survival. Other distant metastases had no significant influence on the prognosis. Pleural effusion gave better prognosis than peritoneal effusion. Patients of breast and lung cancer had longer expectancies, contrasting with those of gastric cancer. Formation of large clusters of cancer cells on smear preparations obtained from the tapped effusions was interpreted as a sign of good prognosis. Frequencies of cancer cell and lymphocyte occurrence on smear preparation did not have any relationship with the prognosis. The results showed that some factors of the patients at malignant effusion accumulating stage did contribute a great deal to their prognosis.

Reye's syndrome with cortical laminar necrosis: MRI

Serial MRI findings are described in two patients with Reyes syndrome, demonstrating diffuse cortical and white matter changes. In the acute stage, T2-weighted images showed subtle but definite laminar high signal and contrast-enhanced T1-weighted images laminar enhancement, along the entire cerebral cortexbilateraly. In the chronic stage, unenhanced T1-weighted images showed diffuse cortical laminar high signal. These characteristic MRI features seemed very similar to those of laminar cortical necrosis in hypoxic brain damage. MRI also displayed delayed white matter changes with cerebral atrophy.

The anterior choroidal artery syndrome

We reviewed 12 cases of infarcts in the territory of the anterior choroidal artery (AChA) on CT and/or MRI. In each case vascular occlusion in the region was verified angiographically. Although the extent of the lesion on CT/MR images was variable, all were located on the axial images within an arcuate zone between the striatium anterolaterally and the thalamus posteromedially. The distribution of the lesions on mutiplanar MRI conformed well to the territory of the AChA demonstrated microangiographically. The variability of the extent of the infarcts may be explained by variations in the degree of occlusive changes in the AChA or the development of collateral circulation through anastomoses between the AChA and the posterior communicating and posterior cerebral arteries. The extent of the lesion appeared to be closely related to the degree of neurological deficit.

Evaluation of large intracranial aneurysm with three-dimensional MRI

Objective The purpose of this study was to evaluate large intracranial aneurysms by contrast-enhanced 3D MRI. Materials and Methods Eleven patients, nine women and two men, were examined. The aneurysms involved the internal carotid artery in seven patients, the middle cerebral artery in one, the basilar artery in two, and the posterior cerebral artery in one. Contrast-enhanced 3D MR images were obtained using FLASH (fast low angle shot) on a 1.5 T system. We obtained axial images first, then sagittal and coronal images by multiplanar reconstruction. Those images were reviewed for comparison with conventional and MR angiography. Results We could easily evaluate the true aneurysmal size, the intraaneurysmal constitution (patent lumen and intraluminal thrombus), and the detailed relationship of the aneurysm to the surrounding vascular and neural structures. Except for the cavernous internal carotid artery, we could identify the aneurysmal neck by carefully observing axial, sagittal, and coronal images. In addition, the progression of intraaneurysmal thrombosis and the patency of the parent arterial lumen after the endovascular treatment were well appreciated. Conclusion We consider that 3D MRI appears to be useful for evaluation of the large intracranial aneurysm.

MR imaging of middle ear cholesteatomas

We prospectively evaluated MR images of 14 patients who had chronic otitis media and who were suspected of having cholesteatomas on otologic examination and/or on high resolution CT. Cholesteatomas were verified in the middle ear and/or mastoid at surgery in nine patients. Cholesteatomas appeared isointense relative to gray matter on T1-weighted spin echo MR images (T1WI) and hyperintense on T2-weighted spin echo MR images (T2WI) in eight patients. Two cholesterol granulomas appeared hyperintense on both T1WI and T2WI. In three patients with chronic otitis media the associated mixed granulation tissue and fluid collection was revealed as nonspecific, heterogeneous signal intensity in two cases. In the third case the signal intensity was similar to that found in cholesteatomas.

Brain CT and MR findings in hyperphenylalaninemia due to dihydropteridine reductase deficiency (variant of phenylketonuria).

Two siblings with malignant hyperphenylalaninemia were examined by magnetic resonance (MR) imaging and CT of the brain. Both techniques demonstrated diffuse cerebral atrophy and cystic loss of parenchyma with surrounding white matter changes. T2-weighted MR images demonstrated the white matter changes better than CT. However, MR images gave no definite indication of the presence of calcification, and CT demonstrated the characteristic calcifications in the basal ganglia and subcortical region bilaterally. Both MR and CT are complementary in the evaluation of this disease.

Retrospective observational study of occult cervical lymph-node metastasis in T1N0 tongue cancer

Objective: Delayed neck metastasis is the most significant prognostic factor for early tongue cancer. The main strategies for controlling cervical lymph nodes in Japan are elective neck dissection or watchful waiting. Elective neck dissection offers significantly better survival, but adversely impacts patient quality of life; consequently, here we investigated how to identify high‐risk patients warranting elective neck dissection. Methods: We retrospectively evaluated 67 patients with T1N0 oral tongue squamous cell carcinoma who underwent primary treatment in our department from April 2001 to March 2015. All the patients underwent watchful waiting alone for neck management. We investigated the rates of occult neck metastasis, prognosis and circumstances of recurrence, and associations with pathological tumor thickness, depth and muscle invasion by the primary tumor. Correlation between the thickness in pathological specimens and that at magnetic resonance imaging was additionally investigated. Results: Neck recurrence was evident in 20 patients, of which 19 developed within 1 year. Therefore, the rate of occult neck metastasis was 29.9%. Patients with muscle invasion, tumor thickness ≥2 mm or tumor depth ≥2 mm on surgical specimens were significantly more likely to develop delayed neck metastasis. Prognosis was significantly worse for patients with muscle invasion or tumor thickness ≥2 mm. Thickness using magnetic resonance imaging was well correlated with pathological thickness. Conclusions: Patients with tumors ≥2 mm in thickness or muscle invasion developed neck metastasis, suggesting that elective neck dissection may be warranted for patients with these findings. For preoperative assessment of the need for elective neck dissection, magnetic resonance imaging would be a potential modality for T1N0 tongue cancer.

Clear cell carcinoma of the nasal cavity: A case report from histopathological viewpoint

We report an extremely rare case of primary clear cell carcinoma (CCC), not otherwise specified (NOS) of the nasal cavity. An 80-year-old woman was referred to our hospital with left nasal obstruction caused by a nasal cavity tumor. The tumor was resected completely with lateral rhinotomy approach. Histopathological examination revealed CCC. CCC metastasis from renal cell carcinoma (RCC), which is at the top of differential diagnosis, was ruled out by the absence of renal tumor at computed tomography (CT). Also, immunohistochemical results of the specimen with vimentin negative and CK7 focally positive excluded the possibility of RCC metastasis. The patient is free from recurrence 1 year after the surgery, and there is no evidence of RCC. In this report histopathological characteristics, especially immunohistochemical properties of primary CCC, NOS of the nasal cavity are presented together with some clinical features of this rare tumor. Also, we refer to histopathogenesis of primary CCC of nasal cavity in relation to myoepithelial carcinoma. Histopathological discussion is further extended to include other CCC and CCC-resembling histologies to confirm the uniqueness of the present case.

MRI of acoustic neuromas

MRI of 51 acoustic neuromas verified surgically or neuro-otologically was reviewed. Tumours were classified according to their size into small ( 25 mm). Twenty-two small neuromas were best demonstrated on T1-weighted images (T1WI) with gadolinium-DTPA. Nineteen medium-sized tumours appeared hypo- to isointense on T1WI and iso- to hyperintense on T2-weighted images (T2WI), and half of them appeared heterogeneous on both T1WI and T2WI. Ten large tumours appeared heterogeneous on both sequences. In 4 of these a hypointense area was seen on T2WI, representing haemosiderin deposition, verified histologically. Signal void was noted at the periphery of 8 tumours, representing the “abnormal veins” described in earlier angiographic studies of acoustic neuroma.