Pediatric presacral tumors with intraspinal extension: a rare entity with diagnostic challenges.

The presacral space is a potential space located between the rectum and the lumbosacral spine. It contains various primitive germ cell types that serve as the origin for a range of tumors. Imaging is crucial in characterizing, assessing the extent of and evaluating the treatment response to these tumors. We report a series of six cases of pediatric presacral tumors with intraspinal extension, including an immature sacrococcygeal teratoma (Altman type II), a malignant sacrococcygeal teratoma (Altman type IV), a neuroblastoma, a rhabdomyosarcoma, a clear cell sarcoma and an Ewing's sarcoma of the ilium. These tumors can be broadly categorized as tumors of germ cell, neuroblastic, mesenchymal and osteogenic origin. Despite overlapping imaging features, a review of the existing literature and careful retrospective observation revealed several distinctive features that aid in the optimal characterization of tumors. These include the tumor's epicenter, the pattern and degree of bone involvement, the status of sacral foramina and neural elements, and internal tumor characteristics such as the presence of fat, calcification, hemorrhage and necrosis.

Cerebrospinal Fluid Flow Analysis in Tuberculous Meningitis Using Phase Contrast Technique on 3 Tesla MRI: A New Paradigm and Our Initial Experience.

Background: Phase-contrast magnetic resonance imaging (PC-MRI) has been used for studying cerebrospinal fluid (CSF) dynamics in various CSF related disorders at aqueduct of Sylvius. Objective: To analyze the CSF flow dynamics qualitatively and quantitatively using PC-MRI across the aqueduct of Sylvius in diagnosed patients of tuberculous meningitis. Methods: Thirty patients, clinically diagnosed with tuberculous meningitis and mean age of 24 years (range: 12-60 years) were taken up to study the changes in CSF flow dynamics using PC-MRI with retrospective cardiac gating. Thirty age and sex matched healthy volunteers were also included for comparison and reference values. Flow quantification was done by through-plane scans acquired in the axial plane perpendicular to the aqueduct. For qualitative examination, in-plane phase contrast scans were acquired in the mid-sagittal plane. Encoding velocity was kept in craniocaudal direction. Calculated parameters were peak velocity (cm/s), average velocity (cm/s), average flow (mL/s), net forward volume (mL), and stroke volume (µL). Results: Qualitatively, loss of normal sinusoidal waveform of CSF flow was noted in two cases of hydrocephalus with exaggerated flows. Quantitatively, CSF flow parameters showed marked numerical difference in tuberculous meningitis patients with hydrocephalus on comparison with healthy volunteers and with cases without hydrocephalus. Conclusion: PC-MRI is a sensitive technique to analyze altered CSF flow dynamics in tuberculous meningitis patients. This is a useful adjunct in imaging these patients to extract both the qualitative and quantitative information about CSF flow for comprehensive evaluation.

Incidentally Diagnosed Extraluminal Leiomyosarcoma of Infrarenal Inferior Vena Cava: A Case Report and Literature Review from a Radiologist's Perspective.

Background: Vascular leiomyosarcoma is a rare but most common vascular tumor of the inferior vena cava. Case presentation: We present the case of an incidentally diagnosed extraluminal leiomyosarcoma of the inferior vena cava in a 62 year old patient who presented with abdominal pain following blunt trauma. Ultrasonography showed a lobulated hypoechoic lesion in the upper abdomen. Computed tomography (CT) and magnetic resonance imaging (MRI) showed a circumscribed lobulated near homogeneously enhancing retroperitoneal lesion in anterior relation to the infrarenal inferior vena cava, right paramedian in location with imperceptible vena caval lumen at the site of maximum contact. In positron emission tomography (PET) CT the lesion showed mild fluorodeoxyglucose (FDG) uptake with no distant metastases. CT guided biopsy with immunohistochemical analysis showed leiomyosarcoma. Patient underwent surgical resection with inferior vena cava reconstruction. Conclusions: Leiomyosarcoma of the inferior vena cava is a rare tumor of vascular origin. Imaging plays an imperative role in the diagnosis and preoperative evaluation. This article also provides a comprehensive literature review of the radiological features of inferior vena caval leiomyosarcoma that would aid in optimal preoperative characterization and evaluation.