Min-Hsiung Chen

Treatment of spinal cord ependymomas by surgery with or without postoperative radiotherapy.

AbstractPurpose: To evaluate the effectiveness of complete resection and postoperative radiotherapy in spinal cord ependymomas. Methods and materials: We conducted a retrospective study over 20 patients (13 males and 7 females) with histologically confirmed spinal cord ependymomas between July 1985 and April 2001. Among them, 13 patients had ependymomas, 6 had myxopapillary ependymomas, and 1 had anaplastic ependymoma. All patients received radical surgery for tumor removal with 13 patients achieving complete resection and 7 incomplete resection due to technical difficulty. Among those with incomplete resection, 6 patients received postoperative radiotherapy to tumor bed and only one patient with anaplastic ependymoma received surgery alone. The total tumor dose ranged from 50 to 60 Gy. Results: Among the 20 patients, 19 patients were alive and showed local control. The median survival time of all patients was 109 months, with 104 months in the complete resection alone group and 135 months in the incomplete resection with postoperative radiotherapy group. One patient with anaplastic ependymoma and no postoperative radiotherapy developed leptomeningeal seeding 9 months after surgery. Salvage therapy of radiotherapy and chemotherapy maintained normal neurological functions. The patient expired 34 months from the initial diagnosis due to progression of leptomeningeal seeding. Conclusion: Complete resection alone in spinal cord ependymoma can achieve excellent local control and survival. Patients should receive complete resection if technically possible. Postoperative radiotherapy is not recommended for complete resection. For incomplete resection, postoperative local radiotherapy is recommended and it can also achieve excellent local control and survival. Local radiotherapy with 50-60 Gy is effective and safe. Salvage radiotherapy improves quality of life for local recurrence or leptomeningeal seeding patients.

Decision model for acute appendicitis treatment with decision tree technology--a modification of the Alvarado scoring system.

Background: How to decide the proper time to do laparotomies for acute appendicitis patients is sometimes very difficult, especially in areas with no imaging diagnostic tools. The Alvarado scoring system (ASS) is a convenient and inexpensive decision making tool; however, its accuracy needs to be improved. The decision tree is the most frequently used data mining technology for diagnostic model building. This study used a decision tree to modify the ASS and to prioritize the variables. Methods: We collected 532 patients who underwent appendectomy. Patients who had undergone incidental appendectomy were excluded from the study. The decision tree algorithm was constructed with the data mining workbench Clementine version 8.1. It is a top‐down algorithm designed to generate a decision tree model with entropy. The algorithm chooses the best decision node with which to separate different classes from empirical data. The Wilcoxon signed rank test, Student t test and χ2 test were used for statistical analysis. Results: Among the 532 patients recruited into the study, 420 had acute appendicitis and 112 had normal appendix. Women with acute appendicitis were older than their male counterparts (p < 0.001). All patients had right lower quadrant tenderness. The new model was constructed with decision tree technology, and the accuracy of the diagnostic rate was better than that of ASS (p < 0.001). The sensitivity and specificity of the new model were 0.945 and 0.805, respectively. Conclusion: The new model is more convenient and accurate than ASS. Right lower quadrant tenderness is an inclusion criterion for acute appendicitis diagnosis. Migrating pain and neutrophil count > 75% were significant factors for acute appendicitis diagnosis if ASS score < 6. Although the criteria of nausea/vomiting and white blood cell count > 10,000/dL were significantly different between acute appendicitis and normal appendix, there was no significant contribution of entropy change below the “neutrophil count > 75%“ nodes in the model. So they were erased from the decision tree model. Further studies need to be conducted to investigate why older women are at higher risk for acute appendicitis.

Massive hemoptysis caused by endobronchial schwannoma in a patient with neurofibromatosis 2.

Neurogenic tumor of the lung is very uncommon. To the best of our knowledge, endobronchial schwannoma complicated by massive hemoptysis in a patient with neurofibromatosis 2 has not been reported previously. We report a case of endobronchial schwannoma complicated by massive hemoptysis in an 18-year-old man with neurofibromatosis 2. The diagnosis of neurofibromatosis 2 was established by demonstration of bilateral vestibular schwannomas on magnetic resonance imaging of the brain and pathologic examination of the resected brain tumors. Massive hemoptysis developed after surgical removal of the brain tumors in this patient. Bronchoscopy was done immediately after the first episode of hemoptysis and a tumor protruding from the orifice of the right lower lobe bronchus was found. Despite 2 additional bronchoscopies to stop bleeding and ameliorate airway obstruction in the consecutive 2 days, hemoptysis recurred rapidly and caused profound oxygen desaturation. The patient was subjected to right lower lobectomy and endobronchial schwannoma was evidenced pathologically.

Olfactory ensheathing cell tumor with neurofibroma-like features: a case report and review of the literature

A 32-year-old man had seizure attack since April 2008 and radiographic examination revealed a heterogeneous enhancing mass at the left subfrontal region. He underwent craniotomy for tumor removal on October 1, 2008. The tumor, which was grayish white with glistening appearance and rubbery consistency, was traced to the proximal part of left olfactory tract. Histopathological examination revealed a hypocellular tumor with dense hyalinization in most areas. The tumor cells had ovoid to elongate and often comma-shaped nucleus. Myxoid change of the stroma was apparent in places. Most of the tumor cells were immuno-reactive for S-100 protein. Staining for Leu 7 (CD57 or HNK-1) was negative. Bodian method illustrated many axons within the tumor. Ultrastructural study of the tumor cells showed features compatible with those of olfactory ensheathing cell. The tumor was designated as olfactory ensheathing cell tumor with neurofibroma-like features. There have been 14 nerve sheath tumors arising from the olfactory nerve reported in the literature; all of them had the morphology of schwannoma. Our case, which had the morphology simulating neurofibroma was the first of its kind to be recorded.

Direct measurement of the signal intensity of diffusion-weighted magnetic resonance imaging for preoperative grading and treatment guidance for brain gliomas

Background: Magnetic resonance diffusion‐weighted imaging (DWI) has been widely used clinically in imaging diagnosis of intracranial disorders. The purpose of current study was to present a quantitative method of direct measuring the DWI signal intensity of brain gliomas on the monitors of hospital picture archiving and communicating system (PACS) for grading gliomas. Methods: This study recruited 135 patients with treatment‐naïve brain gliomas. Direct measurement of the signal intensity of selected tumoral regions of interest (ROIs) by DWI on the monitors of the hospital PACS was performed for all patients. From the measurements, we obtained three values, defined as DWIT (tumor), DWIN (the homologous normal‐appearing area of the tumor ROI in the contralateral hemisphere), and DWIWM (normal‐appearing white matter) in the contralateral frontal lobe. Two ratios, DWIT/WM and DWIT/N, were obtained for each tumoral ROI. The same method was used for apparent diffusion coefficient (ADC) ratios of the tumoral ROI. Fractional polynomial regression and the Mann–Whitney U test were applied to determine the correlation between tumor grading, MIB‐1 labeling index, and DWI and ADC ratios. Logistic regression models and receiver operating characteristic curve analysis were used to establish diagnostic models. Measurements of intraobserver and interobserver agreement were also made at 1‐month interval. Results: The DWI ratios correlated positively with tumor grade and MIB‐1 value (p < 0.01). Cut‐off ratios of 1.62 for DWIT/WM and 1.47 for DWIT/N generated the optimal combination of sensitivity (0.82, 0.80), specificity (0.79, 0.86), and sound discriminating power, with an area under the curve of 0.87 and 0.84, respectively, to differentiate low‐grade from high‐grade gliomas. ADC ratios showed relatively worse sensitivity, specificity, and discriminating power than DWI ratios. Almost all intraobserver and interobserver measurements were within 95% agreement. Conclusion: The proposed method – direct measuring of tumor signal intensity of DWI on PACS monitors – is feasible for grading gliomas in clinical neuro‐oncology imaging services and has a high level of reliability and reproducibility.

Spontaneous intramural intestinal haematoma

An 83-year-old man presented with a 3-day history of progressive abdominal pain and vomiting. He had a 20year history of hypertension and atrial fibrillation andwas taking antihypertensive agents and warfarin. The physical examination showed diffuse abdominal tenderness without rigidity. The routine complete blood count, serum biochemistry profiles were unremarkable except for an increased C reactive protein and prolonged prothrombin time. A plain abdominal radiograph showed distended small bowel loops (Fig. 1). Computed tomography (CT) of the abdomen, without i.v. contrast, showed marked thickening of the wall of the upper jejunum (Fig. 2). The density of the thickened bowel wall ranged from 40 to 60 Hounsfield Units (HU), similar to the density of blood in the abdominal aorta. Anticoagulant-induced intramural intestinal haematomawas diagnosed. The patient received conservative treatment with i.v. fluids and was discharged after7 days.A follow-upabdominalCTscanshowed that the intramural intestinal haematoma had largely resolved (Fig. 3).Hehashadno recurrences and continues todowell. Spontaneous intramural intestinal haematoma is a rare complication of anticoagulant therapy. It is often not suspected clinically and the diagnosis is usually made after abdominal imaging or when exploratory laparotomy is carried out. The non-contrast CT appearance of spontaneous intramural intestinal haematoma was originally described by Plojoux et al. as a hyperdense bowel wall with density ranging from 50 to 80 HU, depending on the time interval between the onset of bleeding and the CT examination. The following CT characteristics should suggest the diagnosis: circumferential wall thickening, intramural hyperdensity, luminal narrowing and intestinal obstruction. In general, conservative therapy is the treatment of choice, whereas surgical intervention is indicated

Fluorescence-assisted visualization of facial nerve during mastoidectomy: A novel technique for preventing iatrogenic facial paralysis

OBJECTIVE Mastoidectomy can be risky due to the chance of iatrogenic facial nerve dysfunction. Avoiding injuries to the mastoid segment of the facial nerve is mandatory when drilling the bone. With advancements in intraoperative near-infrared indocyanine green (ICG) video angiography, we describe the application of a novel fluorescent guidance technique during mastoidectomies to identify the facial canal with safety. METHODS Mastoidectomies were performed as the key step in the presigmoid, petrosal or translabyrinthine approaches in 16 patients with different pathologies located at the cerebellopontine angle or petroclival region. After the facial canal was drilled to paper thin, ICG was injected via the central venous catheter. Compared with the dark bony portion, the vessels inside the vasa nervorum were highlighted as a result. The fluorescence guides the operator through the course of the facial nerve and facilitates opening of the internal auditory canal and the dissection of tumors. RESULTS All 16 facial nerves were recognized during mastoidectomies under fluorescence guidance for varied periods of enhancing time (range, 23-50s). In all, one to four attempts after repeated drilling works to enhance the facial nerve were required before these nerves could be clearly seen. The tumor resection procedure yielded the following results: grossly total removal in seven patients, near total removal in five, and subtotal removal in three. Complete obliteration of a giant vertebral artery aneurysm in one patient was seen in the follow-up angiogram. The post-mastoidectomy facial nerve function, examined by triggered EMG, was preserved in all 16 patients, and no patients had postoperative facial palsy worse than House-Brackmann grade IV after 6 months of follow-up. CONCLUSION With this novel technique, the course of the facial nerve can be confirmed during mastoidectomy, which reduces the possibility of iatrogenic facial nerve dysfunction. This fluorescence technique is especially helpful in establishing confidence and shortening the learning curve for beginners at mastoidectomies.

Rhabdoid glioblastoma: a recently recognized subtype of glioblastoma

BackgroundRhabdoid glioblastoma is a rare type of recently described malignant brain tumor. It is characterized by a glioblastoma associated with rhabdoid components.MethodsHere we report two cases of rhabdoid glioblastoma and a brief literature review. The first patient was a 19-year-old boy who initially presented with a foul-smelling odor and progressive right-side weakness. The second case was a 29-year-old male patient who presented only with a severe headache.ResultsBoth of these patients were young, and the disease progression was quick despite optimal treatment.ConclusionThe diagnosis of rhabdoid glioblastoma was confirmed after microscopic and immunohistochemical findings.

Comparison of the effectiveness of using the optic strut and tuberculum sellae as radiological landmarks in diagnosing paraclinoid aneurysms with CT angiography.

OBJECTIVE The treatment of paraclinoid aneurysms remains challenging. It is important to determine the exact location of the paraclinoid aneurysm when considering treatment options. The authors herein evaluated the effectiveness of using the optic strut (OS) and tuberculum sellae (TS) as radiographic landmarks for distinguishing between intradural and extradural paraclinoid aneurysms on source images from CT angiography (CTA). METHODS Between January 2010 and September 2013, a total of 49 surgical patients with the preoperative diagnoses of paraclinoid aneurysm and 1 symptomatic cavernous-clinoid aneurysm were retrospectively identified. With the source images from CTA, the OS and the TS were used as landmarks to predict the location of the paraclinoid aneurysm and its relation to the distal dural ring (DDR). The operative findings were examined to confirm the definitive location of the paraclinoid aneurysm. Statistical analysis was performed to determine the diagnostic effectiveness of the landmarks. RESULTS Nineteen patients without preoperative CTA were excluded. The remaining 30 patients comprised the current study. The intraoperative findings confirmed 12 intradural, 12 transitional, and 6 extradural paraclinoid aneurysms, the diagnoses of which were significantly related to the type of aneurysm (p < 0.05) but not factors like sex, age, laterality of aneurysm, or relation of the aneurysm to the ophthalmic artery on digital subtraction angiography. To measure agreement with the correct diagnosis, the OS as a reference point was far superior to the TS (Cohens kappa coefficients 0.462 and 0.138 for the OS and the TS, respectively). For paraclinoid aneurysms of the medial or posterior type, using the base of the OS as a reference point tended to overestimate intradural paraclinoid aneurysms. The receiver operating characteristic curve indicated that if the aneurysmal neck traverses the axial plane 2 mm above the base of the OS, the aneurysm is most likely to grow across the DDR and present as a transitional aneurysm (sensitivity 0.806; specificity 0.792). CONCLUSIONS High-resolution thin-cut CTA is a fast and crucial tool for diagnosing paraclinoid aneurysms. The OS serves as an effective landmark in CTA source images for distinguishing between intradural and extradural paraclinoid aneurysms. The DDR is supposed to be located 2 mm above the base of the OS in axial planes.

Gamma knife radiosurgery for lymphoplasmacyte-rich meningioma

Lymphoplasmacyte-rich meningioma with the features of lasmocytoma was first described in 1971 [1]. In 1993, ymphoplasmacyte-rich meningioma was proposed as a variant f meningioma in the World Health Organization classification 2]. Since lymphoplasmacyte-rich meningioma has neoplastic and nflammatory features simultaneously, its biological behavior and rognosis are not so clearly understood. We report a case of ymphoplasmacyte-rich meningioma in a 60-year-old female who nderwent a subtotal surgical resection. However, the residual umor progressed on the suprasellar region one year after opertion, and we arranged Gamma-Knife radiosurgery (GKS) for er. Seven months after GKS, significant tumor shrinkage was oted without any adverse radiation effects (ARE). There is a diference in response to radiation between benign meningiomas nd lymphoplasmacyte-rich meningiomas. This interesting clinical ourse may help us understand more about this rare meningioma.