Hemorrhagic and nonhemorrhagic Rathke cleft cysts mimicking pituitary apoplexy

2008 ◽  
Vol 108 (1) ◽  
pp. 3-8 ◽  
Author(s):  
Mandy J. Binning ◽  
James K. Liu ◽  
John Gannon ◽  
Anne G. Osborn ◽  
William T. Couldwell
Keyword(s):  
Mr Imaging ◽  
Pituitary Tumor ◽  
Pituitary Apoplexy ◽  
Pituitary Tumors ◽  
Imaging Features ◽  
Mr Images ◽  
Acute Hemorrhage ◽  
Consistent Finding ◽  
Imaging Characteristics ◽  
Intracystic Hemorrhage

Object Rathke cleft cysts (RCCs) are infrequently symptomatic, and apoplexy is one of the most unusual presentations. Only a few cases of apoplexy associated with RCCs have been reported, and their clinical, imaging, surgical, and pathological features are poorly understood. In the cases that have been reported, intracystic hemorrhage has been a consistent finding. The authors report 6 cases of RCCs in which the presenting clinical and imaging features indicated pituitary apoplexy, both with and without intracystic hemorrhage. Methods The authors retrospectively reviewed charts and magnetic resonance (MR) imaging studies obtained in patients who underwent transsphenoidal surgery for RCC. Six patients were identified who presented with symptoms and MR imaging characteristics consistent with pituitary apoplexy but were found intraoperatively to have an RCC. All 6 patients presented with a sudden headache, 2 with visual loss, and 1 with diplopia. Review of the preoperative MR images demonstrated mixed signal intensities in the sellar masses suggestive of a hemorrhagic pituitary tumor. In all patients there was a presumed clinical diagnosis of pituitary tumor apoplexy and an imaging-documented diagnosis of hemorrhagic pituitary tumor. Results All 6 patients underwent transsphenoidal resection to treat the suspected pituitary apoplexy. Intraoperative and histopathological findings were consistent with the diagnosis of an RCC in all cases. Only 2 cases showed evidence of hemorrhage intraoperatively. In all cases, an intracystic nodule was found within the RCC at surgery, and this intracystic nodule was present on the initial MR imaging when retrospectively reviewed. The imaging characteristics of the intracystic nodules were similar to those of acute hemorrhage seen in cases of pituitary apoplexy. Conclusions The clinical and imaging features of RCCs appear similar to those of hemorrhagic pituitary tumors, making them often indistinguishable from pituitary apoplexy.

scholarly journals Unusual CT and MR Imaging Characteristics of Splenic Lymphoma

2011 ◽  
Vol 2011 ◽  
pp. 1-3 ◽  
Author(s):  
Chhavi Kaushik ◽  
Nitin Relia ◽  
Kedar Jambhekar ◽  
Tarun Pandey
Keyword(s):  
Mr Imaging ◽  
English Literature ◽  
Vascular Pathology ◽  
Low Density ◽  
Imaging Features ◽  
Focal Lesions ◽  
Imaging Characteristics ◽  
Splenic Lymphoma ◽  
Proven Case ◽  
Common Malignancy

Lymphoma is the most common malignancy of the spleen. The imaging features of splenic lymphoma are nonspecific and mostly lymphomas present as a diffusely enlarged spleen. Focal lesions are described but remain of low density or intensity on CT or MRI, respectively. We describe a histologically proven case of splenic lymphoma that showed an atypical hyperdense/hyperenhancing appearance on imaging suspicious for a vascular pathology. To the best of our knowledge and based on review of English literature, such an appearance of splenic lymphoma is extremely unusual and rare.

Interpretation of magnetic resonance images in diffuse intrinsic pontine glioma: a survey of pediatric neurosurgeons

2011 ◽  
Vol 8 (1) ◽  
pp. 97-102 ◽  
Author(s):  
Todd C. Hankinson ◽  
Elizabeth J. Campagna ◽  
Nicholas K. Foreman ◽  
Michael H. Handler
Keyword(s):  
Mr Imaging ◽  
Online Survey ◽  
Multicenter Trial ◽  
Diffuse Intrinsic Pontine Glioma ◽  
Magnetic Resonance Images ◽  
Imaging Findings ◽  
Mr Images ◽  
Pontine Glioma ◽  
Tumor Biopsy ◽  
Imaging Characteristics

Object The current management paradigm for children with newly diagnosed diffuse intrinsic pontine glioma (DIPG) is to establish a diagnosis and begin therapy based on MR imaging findings correlated with an appropriate clinical presentation, and without a tissue diagnosis. This strategy assumes that pediatric neurosurgeons and neurooncologists uniformly interpret MR imaging findings in this population. This study sought to examine the consistency of North American pediatric neurosurgeons in assessing MR images in this patient population, and in their surgical plans based on the interpretation of those images. Methods The authors created an online survey and invited all members of the American Society of Pediatric Neurosurgeons and the American Association of Neurological Surgeons/Congress of Neurological Surgeons Joint Section for Pediatric Neurosurgery to participate. The survey consisted of 58 questions, and 48 pertained to representative MR images from 16 children who presented to The Children's Hospital of Colorado with diffuse pontine tumors. Based on the imaging presented and a standard clinical scenario, the respondent was asked if she or he believed a lesion to be “typical” or “atypical,” whether she or he would biopsy the lesion, and what surgical approach would be chosen. The remaining 10 questions pertained to respondent demographics and his or her practice regarding tissue preservation and interest in participating in a multicenter trial that included tumor biopsy in selected cases. Rates at which each lesion was considered to be typical or atypical and rates of recommended biopsy were calculated. Results Surveys were received by 269 individuals. Eighty-six responses were received (32.0%). No tumor was judged to be either typical or atypical by all respondents. Individual surgeons varied widely regarding how many of the tumors were judged as typical or warranted a biopsy. The percentage of respondents who disagreed with the majority opinion regarding whether a tumor qualified as typical ranged from 2.3% to 48.8%, with a median of 28.6%. More than 75% agreement regarding whether a tumor was typical or atypical was found in 7 (43.8%) of 16 cases. The κ statistic regarding typicality was 0.297 ± 0.0004 (mean ± SEM), implying only fair agreement. For every tumor, at least 1 respondent who believed the lesion to be typical in appearance would nevertheless biopsy the lesion. Of those respondents who considered a lesion to be typical, a median of 5.1% (range 1.2%–66.7%) would choose to biopsy this lesion. Of those respondents who considered a lesion atypical, a median of 18.3% (range 3.7%–100%) would choose not to biopsy the lesion. Of 85 responses to the question, “Would you be willing to biopsy a typical diffuse pontine glioma as a part of a multicenter trial?,” 59 (69.4%) of 85 respondents answered that they would. Conclusions Although making a diagnosis based on radiographic evidence alone represents a well-established management paradigm for children with suspected DIPG, this study demonstrates considerable inconsistency on the part of pediatric neurosurgeons in the application of this strategy to individual patients. As such, the practice of diagnosing DIPG based on imaging characteristics and clinical history alone does not reach the appropriate threshold to be considered a standard of care.

scholarly journals Differential Diagnosis of Sinonasal Extramedullary Plasmacytoma, Non-Hodgkin’s Lymphoma, and Squamous Cell Carcinoma Using CT Scan and MRI

2021 ◽  
Vol 18 (2) ◽  
Author(s):  
Dong-Joo Lee ◽  
Sang Duk Hong ◽  
Myeong Sang Yu ◽  
Sung Jae Heo ◽  
Joo-Yeon Kim ◽  
...  
Keyword(s):  
Squamous Cell Carcinoma ◽  
Mr Imaging ◽  
Cell Carcinoma ◽  
Tumor Volume ◽  
Cell Lymphoma ◽  
Bone Destruction ◽  
Extramedullary Plasmacytoma ◽  
Imaging Features ◽  
Mr Images ◽  
Waldeyer’S Ring

Background: The imaging features of sinonasal extramedullary plasmacytoma (EMP) are non-specific and similar to those of other lesions, such as sinonasal non-Hodgkin’s lymphoma (NHL) and squamous cell carcinoma (SCC). Objectives: To analyze the computed tomography (CT) and magnetic resonance (MR) images of patients with EMP, NHL, and SCC to identify the radiological characteristics differentiating sinonasal EMP from NHL and SCC. Patients and Methods: In this cross-sectional study, the CT and MR imaging features of 37 patients with sinonasal EMP, 46 patients with NHL, and 44 patients with SCC were analyzed. Sinonasal NHL was categorized into two distinct types, namely, natural killer/T-cell lymphoma (n = 32) and diffuse large B-cell lymphoma (n = 14). The tumor volume was determined by measuring the region of interest (ROI) in the PACS program. Besides, homogeneity, apparent diffusion coefficient (ADC) in the ADC maps, degree of enhancement, adjacent bone destruction, and invasion to Waldeyer’s ring and cervical or retropharyngeal lymph nodes were evaluated. Results: Although the tumor volume was larger in the EMP group as compared to the NHL and SCC groups, the difference was not statistically significant. The NHL group showed the highest tumor homogeneity on both CT and MR images. EMP was more heterogenous than NHL, with moderate signal intensity on T1-weighted MR images. On the other hand, EMP and NHL showed significantly lower ADCs as compared to SCC. The majority of patients with sinonasal EMP, NHL, and SCC showed an avid enhancement. Also, destructive tumor growth involving the adjacent bone was more frequent in SCC than in EMP or NHL. However, there were no significant differences among sinonasal EMP, NHL, and SCC in terms of invasion to Waldeyer’s ring and cervical or retropharyngeal lymph node metastasis. Conclusion: Marked heterogeneity on T1-weighted images, low ADCs, and lack of adjacent bone destruction were the CT and MR imaging features that favored the diagnosis of EMP over NHL or SCC.

Resection of insular gliomas: the importance of lenticulostriate artery position

2008 ◽  
Vol 109 (5) ◽  
pp. 825-834 ◽  
Author(s):  
Yaron A. Moshel ◽  
Joshua D.S. Marcus ◽  
Erik C. Parker ◽  
Patrick J. Kelly
Keyword(s):  
Mr Imaging ◽  
Surgical Techniques ◽  
Brain Parenchyma ◽  
Growth Patterns ◽  
Normal Brain ◽  
Imaging Features ◽  
Mr Images ◽  
Presenting Symptoms ◽  
Group I ◽  
Neurological Morbidity

Object The object of this study was to identify characteristic preoperative angiographic and MR imaging features of safely resectable insular gliomas and describe the surgical techniques and postoperative clinical outcomes. Methods Thirty-eight patients with insular gliomas underwent transsylvian resection between 1995 and 2007. Patient demographics, presenting symptoms, pathological findings, and neurological outcomes were retrospectively reviewed. Preoperative MR imaging–defined tumor volumes were superimposed onto the preoperative stereotactic cerebral angiograms to determine whether the insular tumor was confined lateral to (Group I) or extended medially around (Group II) the lenticulostriate arteries (LSAs). Results Twenty-five patients (66%) had tumors situated lateral to the LSAs and 13 (34%) had tumors encasing the LSAs. Insular gliomas situated lateral to the LSAs led to significant medial displacement of these vessels (161 ± 39%). In 20 (80%) of these 25 cases the boundaries between tumor and brain parenchyma were well demarcated on preoperative T2-weighted MR images. In contrast, there was less displacement of the LSAs (130 ± 14%) in patients with insular gliomas extending around the LSAs on angiography. In 11 (85%) of these 13 cases, the tumor boundaries were diffuse on T2-weighted MR images. Postoperative hemiparesis or worsening of a preexisting hemiparesis, secondary to LSA compromise, occurred in 5 patients, all of whom had tumor volumes that extended medial to the LSAs. Gross-total or near-total resection was achieved more frequently in cases in which the insular glioma remained lateral to the LSAs (84 vs 54%). Conclusions Insular gliomas with an MR imaging–defined tumor volume located lateral to the LSAs on stereotactic angiography displace the LSAs medially by expanding the insula, have well-demarcated tumor boundaries on MR images, and can be completely resected with minimal neurological morbidity. In contrast, insular tumors that appear to surround the LSAs do not displace these vessels medially, are poorly demarcated from normal brain parenchyma on MR images, and are associated with higher rates of neurological morbidity if aggressive resection is pursued. Preoperative identification of these anatomical growth patterns can be of value in planning resection.

scholarly journals Imaging Features of Intracranial Meningiomas with Histopathological Correlation: A Relook into Old Disease

2013 ◽  
Vol 3 (1) ◽  
pp. 14-32
Author(s):  
K Gangadhar ◽  
D Santhosh ◽  
GM Fatterpekar
Keyword(s):  
Mr Imaging ◽  
Signs And Symptoms ◽  
Intracranial Meningioma ◽  
Imaging Features ◽  
Imaging Findings ◽  
Histopathological Correlation ◽  
Imaging Characteristics ◽  
Dural Tail ◽  
Atypical Meningiomas ◽  
Weighted Sequences

Background and Purpose: Imaging characteristics of meningiomas have been discussed previously in many studies; however complete imaging features involving general features, MRS and DWI of both typical and atypical meningiomas have been discussed in very few studies. CT and MR imaging findings in 46 cases of intracranial meningioma are reviewed to define specific imaging features. Methods: The present study was carried on 46 patients in the Department of Radiodiagnosis and Imaging, Institute of Medical Sciences, Banaras Hindu University during June 2009 to July 2011.The investigation was carried out by GE-VCT 64 Slice Scanner machine and Magnetic resonance imaging was contemplated using 1.5 Tesla SIEMENS-MAGNETOM AVANTO. CT and MR imaging studies were reviewed to characterize mass location, imaging characteristics, atypical features and advanced imaging features. Clinical presenting signs and symptoms were correlated with imaging findings. Results: a). Forty six cases of intra cranial meningiomas were studied prospectively in 24 women and 22men, aged 11 – 80 years. Meningiomas were stratified into typical and atypical and also depending upon intra cranial location. b). 73.91% of the cases in showed supratentorial location, rest were infratentorial (26.08%).CT/MRI revealed well defined margins in 84.78% with homogenous consistency in 73.91% of lesions. Foci of necrosis were noted in 32.60% of cases and 15.22% of cases showed calcification foci in meningioma. Sinus invasion noticed in 15.22% of cases, whereas adjacent bony reaction noticed in 30.43% of cases. c). Majority of Meningioma showed broad dural base (89.10%), adjacent white matter buckling (71.74%) and surrounding CSF cleft (52.17%). Displaced subarachnoid vessels were demonstrated in 30.43%, where as the pathognomonic dural tail was present in only 23.91% of the cases. d). All the cases of Meningioma demonstrated restriction on diffusion weighted sequences suggestive of high cellularity of the lesions. On CT angiography, neovascularity was noticed in 85.71% and tumor blush was noticed in 71.42% incidence. On MR Spectroscopy, all demonstrated choline peak and in one third cases alanine peak was discernible. Conclusion: In view of the observed evidence, it was concluded that understanding the classification, pathology and imaging appearance meningioma are essential for treatment planning. CT and MR imaging play indispensable role in the localization & characterization of these tumors, and MR have virtually yielded its position of dominance in characterizing these tumors. Nepalese Journal of Radiology / Vol.3 / No.1 / Issue 4 / Jan-June, 2013 / 14-32 DOI: http://dx.doi.org/10.3126/njr.v3i1.8713

Lhermitte-Duclos disease mimicking adult-onset aqueductal stenosis

1994 ◽  
Vol 80 (6) ◽  
pp. 1095-1098 ◽  
Author(s):  
Shah N. Siddiqi ◽  
Michael G. Fehlings
Keyword(s):  
Mr Imaging ◽  
Benign Lesion ◽  
Aqueductal Stenosis ◽  
Cerebellar Hemisphere ◽  
Imaging Features ◽  
Adult Onset ◽  
Full Spectrum ◽  
Content Type ◽  
Weighted Image ◽  
Imaging Characteristics

✓ Lhermitte-Duclos disease is a rare lesion characterized by enlarged cerebellar folia containing abnormal ganglion cells. This case report describes a 51-year-old woman who was initially misdiagnosed as having adult-onset aqueductal stenosis. There were no abnormal findings on computerized tomography (CT), but subsequent magnetic resonance (MR) imaging showed a midline cerebellar lesion extending to the brain stem. This is a unique case of Lhermitte-Duclos disease arising within the cerebellar vermis. The characteristic feature of an enlarged cerebellar hemisphere is absent on CT scans; thus MR imaging is needed to confirm the diagnosis. If diagnosed late, this generally benign lesion becomes difficult to resect totally and has a poorer prognosis. Only two reports have mentioned the MR imaging characteristics of Lhermitte-Duclos disease; both described only T2-weighted images. This case illustrates the full spectrum of MR imaging features of this disease. Both T1- and T2-weighted studies showed enlarged cerebellar folia within the lesion. The T1-weighted image showed a mixed iso- and hypodense signal and the T2-weighted image a homogeneously increased signal; with gadolinium administration the lesion did not enhance. The latter feature supports the theory that this disease is a hamartoma rather than a tumor.

Symptomatic intracystic hemorrhage in pineal cysts

2009 ◽  
Vol 4 (2) ◽  
pp. 130-136 ◽  
Author(s):  
Sevgi Sarikaya-Seiwert ◽  
Bernd Turowski ◽  
Daniel Hänggi ◽  
Giesela Janssen ◽  
Hans-Jakob Steiger ◽  
...  
Keyword(s):  
Mr Imaging ◽  
Severe Headache ◽  
Neurological Symptoms ◽  
Surgical Removal ◽  
Fluid Interface ◽  
Mr Images ◽  
Pineal Cyst ◽  
Cerebral Disease ◽  
Characteristic Structure ◽  
Intracystic Hemorrhage

Pineal cysts are benign and often asymptomatic intracranial entities. Occasionally they can lead to neurological symptoms through growth or due to intracystic hemorrhage. The purpose of the current report is to describe their clinical characteristics and treatment options. In the current study, the authors illustrate the course of disease in 3 patients who developed neurological symptoms due to hemorrhage into a pineal cyst. Two of their patients had additional cerebral disease, and regular MR imaging examinations were conducted. This circumstance allowed documentation of growth and intracystic hemorrhage. After the occurrence of new neurological symptoms with severe headache, MR images showed a fluid-fluid interface due to intracystic hemorrhage. The third patient presented with acute triventricular hydrocephalus and papilledema due to aqueductal stenosis caused by intracystic hemorrhage. In all 3 cases, excision of the pineal cysts via an infratentorial/supracerebellar approach was performed. Histological examination revealed the characteristic structure of pineal cyst in all cases, with hemorrhagic residues in the form of hemosiderin deposits. All patients recovered fully after surgical removal of the cysts. Furthermore, resolution of occlusive hydrocephalus could be demonstrated in those cases with ventricular enlargement. Pineal cysts without neurological symptoms are often discovered as incidental findings on cranial MR images. In contrast, neurological symptoms such as severe headache, diplopia, or Parinaud syndrome, may occur as a result of pineal apoplexy due to intracystic hemorrhage. The authors' cases confirm that MR imaging can identify intracystic hemorrhage by a characteristic fluid-fluid interface. Their experience suggests that microsurgical resection of cysts may be an effective and curative treatment option.

scholarly journals Hyponatremia as the Initial Presentation of Evolving Pituitary Apoplexy

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. A586-A586
Author(s):  
Jovan Milosavljevic ◽  
Asha Mary Thomas
Keyword(s):  
Mental Status ◽  
Pituitary Apoplexy ◽  
Pituitary Tumors ◽  
Altered Mental Status ◽  
Clinical Syndrome ◽  
Medical Emergency ◽  
Fluid Restriction ◽  
Free T4 ◽  
Acute Hemorrhage ◽  
Initial Testing

Abstract Pituitary apoplexy (PA) is a known, often under-recognized medical emergency and is characterized by ischemic or hemorrhagic necrosis of the pituitary gland. It is a rare clinical syndrome that occurs in 2-12% of pituitary tumors. Hyponatremia can occur secondary to hypocortisolism (12-40%) or, rarely, to the syndrome inappropriate antidiuretic hormone (ADH) secretion. We present the case of a 69-year-old man who presented with altered mental status on post-operative day 3 from total knee replacement surgery. Initial testing revealed hyponatremia of 124 mmol/L, low serum osmolality of 266 mOsm/kg, and high urine osmolality of 664 mOsm/kg with urine sodium of 179 mmol/L. Head computerized tomography revealed a sellar mass of 1.8 x 2.4 cm. Initial testing revealed low prolactin (0.7 ng/mL), normal TSH (0.458 mcIU/mL) with borderline low free T4 of 0.72 ng/dL. Morning cortisol was 12.7 mcg/dL with ACTH of 8.5 pg/mL. Cosyntropin stimulation test was done revealing baseline cortisol of 5.8 mcg/dL (at midnight), increasing to 25.8 mcg/dL after 30 minutes and to 30.9 mcg/dL 60 minutes after cosyntropin administration. His sodium and mental status initially improved with fluid restriction and salt tablets, for the assumed syndrome of inappropriate ADH secretion. The patient remained hemodynamically stable. On the fourth day, however, his mental status deteriorated. Magnetic resonance imaging revealed expansion of sella with hyperintense mass 2.2 x 2.0 x 2.8 cm with compression of the optic chiasm. He was given stress dose hydrocortisone and levothyroxine and underwent emergency transsphenoidal resection. Biopsy revealed acute hemorrhage within infarcted adenoma. Postoperatively, both the patient’s sodium and mental status improved significantly and he was discharged to home on hydrocortisone and levothyroxine. The main clinical concern in the management of PA remains under-diagnosis at presentation. Prognosis is dependent on management during the acute phase. PA can present as hyponatremia even in the absence of overt hypocortisolism, presumably due to inappropriate ADH secretion. Therefore, PA should be considered as one of the differential diagnoses in hemodynamically stable patients with altered mental status and hyponatremia.

The natural history of familial cavernous malformations: results of an ongoing study

1994 ◽  
Vol 80 (3) ◽  
pp. 422-432 ◽  
Author(s):  
Joseph M. Zabramski ◽  
Thomas M. Wascher ◽  
Robert F. Spetzler ◽  
Blake Johnson ◽  
John Golfinos ◽  
...  
Keyword(s):  
Natural History ◽  
Mr Imaging ◽  
Ongoing Study ◽  
Mr Images ◽  
Cavernous Malformations ◽  
Content Type ◽  
Imaging Characteristics ◽  
Familial Form ◽  
Fine Print

✓ Cavernous malformations are congenital abnormalities of the cerebral vessels that affect 0.5% to 0.7% of the population. They occur in two forms: a sporadic form characterized by isolated lesions, and a familial form characterized by multiple lesions with an autosomal dominant mode of inheritance. The management of patients with cavernous malformations, particularly those with the familial form of the disease, remains a challenge because little is known regarding the natural history. The authors report the results of an ongoing study in which six families afflicted by familial cavernous malformations have been prospectively followed with serial interviews, physical examinations, and magnetic resonance (MR) imaging at 6- to 12-month intervals. A total of 59 members of these six families were screened for protocol enrollment; 31 (53%) had MR evidence of familial cavernous malformations. Nineteen (61%) of these 31 patients were symptomatic, with seizures in 12 (39%), recurrent headaches in 16 (52%), focal sensory/motor deficits in three (10%), and visual field deficits in two (6%). Twenty-one of these 31 patients underwent at least two serial clinical and MR imaging examinations. A total of 128 individual cavernous malformations (mean 6.5 ± 3.8 lesions/patient) were identified and followed radiographically. During a mean follow-up period of 2.2 years (range 1 to 5.5 years), serial MR images demonstrated 17 new lesions in six (29%) of the 21 patients; 13 lesions (10%) showed changes in signal characteristics, and five lesions (3.9%) changed significantly in size. The incidence of symptomatic hemorrhage was 1.1% per lesion per year. The results of this study demonstrate that the familial form of cavernous malformations is a dynamic disease; serial MR images revealed changes in the number, size, and imaging characteristics of lesions consistent with acute or resolving hemorrhage. It is believed that the de novo development of new lesions in this disease has not been previously reported. These findings suggest that patients with familial cavernous malformations require careful follow-up monitoring, and that significant changes in neurological symptoms warrant repeat MR imaging. Surgery should be considered only for lesions that produce repetitive or progressive symptoms. Prophylactic resection of asymptomatic lesions does not appear to be indicated.

scholarly journals Peroneal and tibial intraneural ganglia: correlation between intraepineurial compartments observed on magnetic resonance images and the potential importance of these compartments

2007 ◽  
Vol 22 (6) ◽  
pp. 1-10 ◽  
Author(s):  
Robert J. Spinner ◽  
Kimberly K. Amrami ◽  
Diana Angius ◽  
Huan Wang ◽  
Stephen W. Carmichael
Keyword(s):  
Magnetic Resonance ◽  
Sciatic Nerve ◽  
Mr Imaging ◽  
Tibial Nerve ◽  
Cyst Formation ◽  
Magnetic Resonance Images ◽  
Imaging Features ◽  
Mr Images ◽  
Superior Tibiofibular Joint ◽  
Tibiofibular Joint

Object Previously the authors demonstrated that peroneal and tibial intraneural ganglia arising from the superior tibiofibular joint may occasionally extend proximally within the epineurium to reach the sciatic nerve. The dynamic nature of these cysts, dependent on intraarticular pressures, may give rise to differing clinical and imaging presentations that have remained unexplained until now. To identify the pathogenesis of these unusual cysts and to correlate their atypical magnetic resonance (MR) imaging appearance, the authors retrospectively reviewed their own experience as well as the published literature on these types of intraneural ganglia. Methods A careful review of MR images obtained in 22 patients with intraneural ganglia located about the knee region (18 peroneal and four tibial intraneural ganglia) allowed the authors to substantiate three different patterns: outer (epifascicular) epineurial (20 cases); inner (interfascicular) epineurial (one case); and combined outer and inner epineurial (one case). In these cases serial MR images allowed the investigators to track the movement of the cyst within the same layer of the epineurium. All lesions had connections to the superior tibiofibular joint. Nine patients were identified as having lesions with sciatic nerve extension. Seven patients harboring an outer epineurial cyst (six in whom the cyst involved the peroneal nerve and one in whom it involved the tibial nerve) had signs of sciatic nerve cross-over, with the cyst seen in the sciatic nerve and/or other terminal branches. In only two of these cases had the cyst previously been recognized to have sciatic nerve involvement. In contrast, in one case an inner epineurial cyst involving the tibial nerve ascended within the tibial division of the sciatic nerve and did not cross over. A single patient had a combination of both outer and inner epineurial cysts; these were easily distinguished by their distinctive imaging patterns. Conclusions This anatomical compartmentalization of intraneural cysts can be used to explain varied clinical and imaging patterns of cleavage planes for cyst formation and propagation. Compartmentalization elucidates the mechanism for cases of outer epineurial cysts in which there are primary ascent, sciatic cross-over, and descent of the lesion down terminal branches; correlates these cysts' atypical MR imaging features; and contrasts a different pattern of inner epineurial cysts in which ascent and descent occur without cross-over. The authors present data demonstrating that the dynamic phases of these intraneural ganglia frequently involve the sciatic nerve. Their imaging features are subtle and serve to explain the underrecognition and underreporting of the longitudinal extension of these cysts. Importantly, cysts extending to the sciatic nerve are still derived from the superior tibiofibular joint. Combined with the authors' previous experimental data, the current observations help the reader understand intraneural ganglia with a different, deeper degree of anatomical detail.

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