Successful Treatment of Refractory Langerhans Cell Histiocytosis of the Choroid Plexus in a Child With Pulse Dexamethasone and Lenalidomide.

Refractory/relapsed Langerhans cell histiocytosis (LCH) has a difficult course with a guarded prognosis. Salvage treatments available are both expensive and highly toxic. On the basis of the pathophysiology of LCH, we used a novel protocol including pulse dexamethasone and lenalidomide in a child with refractory LCH involving the choroid plexus, which resulted in durable remission with minimal toxicity. The protocol was extrapolated from the FIRST trial for patients with multiple myeloma. We present the clinical course, treatment protocol, and outcome in this child, who is at present disease free and in remission 18 months posttreatment.

Computer-assisted delineation of cerebral infarct from diffusion-weighted MRI using Gaussian mixture model.

PURPOSE: Diffusion-weighted imaging (DWI) is a widely used medical imaging modality for diagnosis and monitoring of cerebral stroke. The identification of exact location of stroke lesion helps in perceiving its characteristics, an essential part of diagnosis and treatment planning. This task is challenging due to the typical shape of the stroke lesion. This paper proposes an efficient method for computer-aided delineation of stroke lesions from DWI images. METHOD: Proposed methodology comprises of three steps. At the initial step, image contrast has been improved by applying fuzzy intensifier leading to the better visual quality of the stroke lesion. In the following step, a two-class (stroke lesion area vs. non-stroke lesion area) segmentation technique based on Gaussian mixture model has been designed for the localization of stroke lesion. To eliminate the artifacts which would appear during segmentation process, a binary morphological post-processing through area operator has been defined for exact delineation of the lesion area. RESULT: The performance of the proposed methodology has been compared with the manually delineated images (ground truth) obtained from different experts, individually. Quantitative evaluation with respect to various performance measures (such as dice coefficient, Jaccard score, and correlation coefficient) shows the efficient performance of the proposed technique.

Magnetic resonance imaging of diabetic muscle infarction: report of two cases.

Diabetic muscle infarction (DMI) occurs as a rare complication of long standing or severe diabetes mellitus. The condition usually occurs spontaneously and patients usually present with acute pain and swelling of affected muscles which persists for weeks, and resolves spontaneously without intervention. Magnetic resonance (MR) imaging is the modality of choice in patients with suspected DMI based on appropriate clinical setting and plays a major role in the diagnosis, assessing the extent of involvement and differentiating DMI from other conditions. The DMI affected muscles are bulky and appear heterogeneous with hyperintense signals on T2-weighted and STIR sequences, hypo or isointense on T1-weighted images with loss of normal fatty intramuscular septae. Subcutaneous and perifascial edema can be present. On postgadolinium scans, there is diffuse heterogeneous enhancement with non-enhancing foci, which may represent areas of necrosis. Biopsy can be avoided as MR findings are highly sensitive and specific. Treatment is usually conservative. Surgical intervention is required only in patients who do not respond to conservative management. The common differential diagnosis includes cellulitis, abscess, necrotizing fasciitis and polymyositis. We present two cases below to highlight the clinical, MR imaging findings and differential diagnosis of DMI.

Cystic Lymphangioma of the Breast: Magnetic Resonance Imaging Features.

BACKGROUND: The aim of this study was to report magnetic resonance imaging (MRI) features of cystic lymphangiomas of the breast. METHODS: MRI of the breast was performed using a phased-array double breast coil with a 1.5-T MR scanner. Routine T1 and T2 and post-contrast sequential imaging was performed. RESULTS: The MRI characteristics of cystic lymphangioma in the breast are described. CONCLUSION: MR imaging provides for multiplanar evaluation and diagnosis of cystic lymphangioma of the breast, which is a rare occurrence.

A rare case of solitary fibrous tumour of the sigmoid mesocolon: imaging features and review of literature.

Solitary fibrous tumours are rare spindle cell tumours that generally arise from the pleura but on rare occasions arise in other locations such as the head and neck region, stomach and retroperitoneum. Very few reports exist on the imaging findings of these tumours in extra pleural sites such as the mesentery. We report the computed tomography (CT) imaging findings of a rare case of solitary fibrous tumour in a 68-year-old man who presented with a slowly enlarging painless pelvic mass. CT scan showed a well-defined, multilobulated, highly vascular pelvic mass with dense calcifications and central hypoatteunating areas arising from the mesentery.

Ovarian carcinoma metastasis to the breast and imaging features with histopathologic correlation: a case report and review of the literature.

Metastasis to the breast from primary ovarian carcinoma is rare. We describe a case in which the patient developed breast metastasis 3 years after initial treatment of a primary ovarian cancer.

Neuroimaging patterns of central nervous system metastases in neuroblastoma: report of 2 recent cases and literature review.

The authors describe imaging patterns of intracranial metastases in 2 children with grade 4 neuroblastoma. Central nervous system metastases from neuroblastoma are extremely rare and may involve the cerebral parenchyma, leptomeninges, or dura. Cerebral parenchymal metastases can be cystic with mural nodules or solid with hemorrhagic elements. The first patient in our study had multiple cystic parenchymal metastases with calcific mural nodules, while the second patient developed solid hemorrhagic parenchymal metastatic lesions along with extensive leptomeningeal and dural deposits. Central nervous system involvement in both patients occurred within a time span ranging from 12 to 14 months from the time of initial diagnosis.

Imaging of desmoplastic infantile ganglioglioma: a spectroscopic viewpoint.

PURPOSE: Desmoplastic infantile gangliogliomas (DIG) are rare benign intracranial neoplasms of early childhood with involvement of superficial cerebral cortex and leptomeninges. The purpose of the study was to determine the alterations in metabolite ratios occurring in the neoplasm and combine with magnetic resonance (MR) imaging features to narrow down the diagnosis. METHODS: MR imaging sequences include T1- and T2-weighted sequences, fluid-attenuated inversion recovery sequences, and post-gadolinium-contrast T1-weighted imaging. Single-voxel short TE (1)H MR spectroscopy was used to study the changes in metabolite ratios in the tumor. RESULTS: Comparison of metabolite ratios between normal brain tissue and tumor-affected region showed lower N-acetyl aspartate to creatine (Cr; 1.58 vs.1.28), higher choline to Cr (0.82 vs.2.03), and no significant change in myo-inositol to Cr (0.42 vs.0.39). CONCLUSION: MR spectroscopy and imaging provide valuable information in the diagnosis of DIG.

Magnetic Resonance Imaging of a Benign Phyllodes Tumor of the Breast.

SUMMARY: BACKGROUND: The aim of this study was to evaluate a phyllodes tumor of the breast with magnetic resonance imaging (MRI) and magnetic resonance spectroscopy. METHODS: MRI of the breasts was performed using a phased array double breast coil with spectroscopic capability on a 1.5T MR scanner. Post-contrast sequential imaging was done, and the subtracted images were evaluated. Timesignal intensity curves were obtained. MR spectroscopy using BREASE software was also performed. RESULTS: MRI combined with MR spectroscopy was used in the diagnosis and characterization of a phyllodes tumor of the breast. CONCLUSION: MRI and MR spectroscopy may offer an in vivo imaging technique for the characterization of phyllodes tumors of the breast.

CT imaging of malignant metastatic hemangiopericytoma of the parotid gland with histopathological correlation.

We report an extremely rare case of malignant hemangiopericytoma (HPC) of the parotid gland and its metastatic spread to lung, liver, and skeletal muscle. Computed tomography (CT) imaging, histopathological and immunohistochemical methods were employed to study the features of malignant HPC and its metastases. CT imaging was helpful to determine the exact location, involvement of adjacent structures and vascularity, as well as evaluating pulmonary, hepatic, peritoneal, and muscular metastases. Immunohistochemical and histopatholgical features of the primary tumor as well as the metastases were consistent with the diagnosis of malignant HPC.

Longitudinal CT and MR appearances of hemimegalencephaly in a patient with tuberous sclerosis.

CASE REPORT: A 3-day-old baby was referred to our institution with seizures since birth and a presumptive diagnosis of cerebral tumor detected by prenatal ultrasound. Computed tomography (CT) and Magnetic Resonance (MR) imaging performed immediately after birth revealed the presence of an enhancing mass in the left cerebral hemisphere. DISCUSSION: The possibility of a congenital malignant brain tumor was considered. Although surgery was advised, the parents opted for conservative medical management. The infant was under treatment for seizures with antiepileptic drugs. At 7-month follow-up, there was a noticeable increase in the seizure activity with signs of developmental delay and increased head circumference. Repeat CT and MR imaging showed features of hemimegalencephaly with a calcified mass involving the left hemisphere. The patient was diagnosed to have tuberous sclerosis. This case report illustrates how an enhancing mass (possibly a tuber) over a period of time diminishes in size and becomes calcified in a patient with tuberous sclerosis and associated hemimegalencephaly.