A Dorsally Located Endodermal Cyst in the Foramen Magnum Mimicking an Arachnoid Cyst: A Case Report.

INTRODUCTION: Endodermal cysts are congenital benign cystic lesions in the central nervous system and cause various symptoms. Although some have been reported in the posterior fossa, endodermal cysts located dorsal to the brainstem are extremely rare. CASE PRESENTATION: The case was of a 10-year-old girl who presented with bilateral upper limb weakness and tremor. Magnetic resonance imaging demonstrated a 4.5-cm cystic lesion with T1-weighted hypointense and T2-weighted hyperintense content in the midline of the cisterna magna dorsal to the medulla oblongata. The cyst was cerebrospinal fluid-like, causing us to suspect a symptomatic arachnoid cyst. The lucent cyst wall had no apparent attachment, and complete recovery ensued following total excision of the cyst wall. Pathology confirmed a diagnosis of endodermal cyst. DISCUSSION/CONCLUSION: Herein, we review the past literature on this rare entity. An endodermal cyst in the cisterna magna tends to be less strongly attached and to show a cerebrospinal fluid-like component on magnetic resonance images that mimics an arachnoid cyst. The characteristics of dorsally located endodermal cysts may differ from those in other locations.

A Presenile Patient with Filar Lipoma Who Developed Tethered Spinal Cord Syndrome Triggered by Lumbar Canal Stenosis.

Lumbar canal stenosis (LCS) has been reported as a precipitating factor by which a tethered spinal cord, which is asymptomatic during childhood, develops into tethered cord syndrome (TCS) in adulthood. However, only a few reports on surgical strategies for such cases are available. A 64-year-old woman presented with unbearable pain in the left buttock and dorsal aspect of the thigh approximately 1 year ago. Magnetic resonance imaging showed cord tethering with a filar-type spinal lipoma and LCS due to the thickening of the ligamentum flavum at the L4-5 vertebral level. Five months after the decompressive laminectomy for the treatment of LCS, an untethering surgery was performed at the dural cul-de-sac at the S4 level. The severed end of the filum was elevated rostrally by 7 mm, and the pain subsided postoperatively. This case study shows that surgeries for both lesions should be indicated for adult-onset TCS triggered by LCS.

High prevalence of acetabular retroversion in both affected and unaffected hips after Legg-Calvé-Perthes disease.

BACKGROUND: Acetabular retroversion is observed in hips after various pediatric hip diseases. This study sought to examine the frequency of acetabular retroversion in both affected and unaffected hips after Legg-Calvé-Perthes disease and its correlation with the prominence of the ischial spine. METHODS: We retrospectively investigated the version and morphological features of the acetabulum using pelvic radiographs after Legg-Calvé-Perthes disease (107 affected hips treated non-operatively and 72 unaffected hips from the contralateral side). The diagnosis of acetabular retroversion was made based on the presence of a positive cross-over sign on anteroposterior pelvic radiographs. The correlation between the presence of a positive cross-over sign and modified Stulberg classes, the onset age of Legg-Calvé-Perthes disease, radiographic parameters for acetabular dysplasia and the prominence of the ischial spine were examined. RESULTS: The prevalence of a positive cross-over sign was 49.5 % (45 of 91 hips) in affected hips and 45.8 % (33 of 72 hips) in unaffected hips. Hips with a positive cross-over sign were significantly coexistent bilaterally. The prevalence of prominence of the ischial spine in the positive cross-over sign group was 71.4 % in the affected side and 81.8 % in the unaffected side, indicating a significant correlation between the cross-over sign and the prominence of the ischial spine in both affected and unaffected hips. The positive cross-over sign did not have any correlation with the parameters for acetabular dysplasia and the onset age, however, had a significant correlation with the severity of the femoral head deformity. CONCLUSIONS: High prevalence of acetabular retroversion in both affected and unaffected hips after Legg-Calvé-Perthes disease was demonstrated. Symmetric acetabular deformity and the coexistence of prominence of the ischial spine suggested the effects of the Legg-Calvé-Perthes disease lesions on the skeletal development of the whole pelvis. Further follow-up is needed to clarify the pathological significance of acetabular retroversion after Legg-Calvé-Perthes disease.

Solitary fibrous tumor of the pineal region in the elderly: A case report.

INTRODUCTION: Solitary fibrous tumor (SFT) is a mesenchymal tumor with spindle cells that is often detected in the subcutaneous area and rarely in the central nervous system. Intracranial SFTs rarely occur in individuals older than 80 years, and there are only a few cases reports involving the pineal region. PRESENTATION OF CASE: The present case was an 80-year-old man with lightheadedness, headache, and vomiting. Magnetic resonance imaging showed a tumor in the pineal region extending along the falx and tentorium cerebelli with homogenous enhancement. Subtotal resection was performed via the occipital transtentorial approach. A histopathological examination showed the proliferation of oval- to spindle-shaped tumor cells with bland nuclei arranged in a haphazard pattern and accompanied by staghorn-like branching vessels. Immunohistochemically, tumor cells were positive for CD34 (focal), CD99, and STAT6, but negative for epithelial membrane antigen (EMA) and S-100. Based on these findings, the tumor was diagnosed as SFT (WHO grade I). DISCUSSION: Although difficulties are associated with differentiating SFT from meningioma on imaging, recurrence and metastasis are more common with SFT than with meningioma; therefore, histological and immunohistochemical analyses are important. A correlation has been reported between postoperative adjuvant radiotherapy and longer progression-free survival; however, this needs to be confirmed in further studies. CONCLUSION: SFT involving the pineal region is rare in the elderly, but needs to be considered as a preoperative diagnosis. Since high rates of postoperative recurrence and metastasis have been reported, long-term follow-ups are required after surgery.