Microcystic meningiomas: radiological characteristics of 16 cases

Summary Background. As a rare subtype of meningioma, only a few reports deal with radiological characteristics of microcystic meningiomas and the problem remains controversial. The authors have analyzed the radiological findings of a series of microcystic meningiomas with a special focus on magnetic resonance images (MRI) and conventional angiography.Method. Sixteen patients of histologically proven microcystic meningiomas were included. Analysis of preoperative MRI including signal intensity characteristics, enhancement patterns and peritumoural edema were performed and correlated with angiographic and histological findings. Peritumoural edema was graded using edema index (EI) which was defined as the ratio of V_E/V_T.Findings. The tumours were uniformly visualized as a high-signal mass lesion in T2-weighted images and as a low-signal mass lesion in T1-weighted images regardless of tumour vascularity shown by angiography. T2-weighted images revealed that peritumoural brain edema was severe in 11, moderate in 1, mild in 2 and negligible in 2 patients and this was closely related to the co-existence of irregular tumour marginal enhancement. However, other features failed to distinguish these lesions from other subtypes of meningioma.Conclusions. The cases presented demonstrate that characteristic MRI findings suggestive of microcystic meningiomas are; (1) low signal intensity mass in T1- and high signal intensity mass in T2-weighted images; (2) high incidence of peritumoural edema.     

Unilocular macrocystic serous cystadenoma of the pancreas: a morphologic variant to be considered

Serous cystadenoma of the pancreas is a benign cystic tumor, which radiological diagnosis is easy in its typical microcystic variant. The macrocystic variant is uncommon and raises diagnostic problems with other macrocystic lesions of the pancreas such as pseudocysts and mucinous cystadenomas. We report the case of a young woman with a unilocular macrocystic serous cystadenoma of the pancreas which was identified on pathologic examination of the surgical specimen, after unconclusive abdominal ultrasound and CT-scan. This case describes an unusual clinical presentation of this cystic tumor and emphasizes that the diagnosis of such an entity is still based on pathological examination after cyst removal.     

Unique Imaging Features of Spinal Neurenteric Cyst

A 50-year-old male presented with acutely progressed paraplegia. His magnetic resonance imaging demonstrated two well-demarcated components with opposite signals in one cystic lesion between the T1- and T2-weighted images at the T1 spine level. The patient showed immediately improved neurological symptoms after surgical intervention and the histopathological exam was compatible with a neurenteric cyst. On operation, two different viscous drainages from the cyst were confirmed. A unique similarity of image findings was found from a review of the pertinent literature. The common findings of spinal neurenteric cyst include an isointense or mildly hyperintense signal relative to cerebrospinal fluid for both T1- and T2-weighted images. However, albeit rarer, the signals of some part of the cyst could change into brightly hyperintensity on T1-weighted images and hypointensity on T2-weighted images due to the differing sedimentation of the more viscous contents in the cyst.     

Serous Adenoma of the Pancreas With Multiple Microcysts Communicating With the Pancreatic Duct

The rare neoplastic cystic adenomas of the pancreas form two groups of tumors: macrocystic mucinous and microcystic serous adenomas. Both entities show specific radiologic and histologic features. Several recent case reports, however, suggest some diversity within the group of microcystic serous adenomas. We present the case of a young man operated because of epigastric pain for 12 months and a palpable microcystic tumor of the pancreatic head. Multiple cysts communicating with branches of the pancreatic duct in an alveolar-like pattern were demonstrated on endoscopic retrograde cholangiopancreatography. Histologic examination of the specimen confirmed the diagnosis of a serous adenoma of the pancreas. The tumor morphology in this case may suggest a ductal origin of microcystic serous adenomas.     

胰腺囊性肿瘤的诊断与治疗

自１９６５～１９９４年，作者收治了１６例胰腺囊性肿瘤病人。男性４例，女性１２例，平均年龄５０９岁。１６例中浆液性囊腺瘤２例，良性的粘液性囊腺瘤７例，粘液性囊腺癌４例，乳头状囊腺癌１例，低分化腺癌１例，未分化癌１例。Ｂ超和ＣＴ检查对于肿物的检出、浆液性囊腺瘤内多发小囊的分辨，以及肿物周边钙化的显示具有一定价值。囊肿壁不完全的活组织检查可导致冰冻甚至石腊切片的误诊。除了个别已被确诊的无症状的浆液性囊腺瘤可进行观察，其余各种类型的病变均要行手术切除。本文对各种类型囊性肿瘤的特征、囊性肿瘤与假性囊肿的鉴别诊断以及各类手术方式进行了讨论。     

Association d’un kyste arachnoïdien et d’une hétérotopie de tissu glial dans le méat auditif interne

ObjectivesWe report a case of an association of an arachnoid cyst with heterotopic neuroglial tissue in the internal auditory canal.Material and methodsA 66-year-old woman consulted for cochleovestibular syndrome.ResultsMRI demonstrated a lesion with spontaneous hypersignal on T1- and T2-weighted images, instigating surgical exploration. We discovered a hematic arachnoid cyst associated with heterotopic neuroglial tissue arising in the internal auditory canal.ConclusionAn arachnoid cyst arising within the cerebellopontine angle or the internal auditory canal is a rare occurrence. Clinical manifestations are identical with those produced by a cochleovestibular schwannoma. MRI usually demonstrates a nonenhancing isointense cystic mass with cerebrospinal fluid on all sequences (hypointense on T1-weighted and hyperintense on T2-weighted images). These lesions are usually monitored. Spontaneous hypersignal on T1- and T2-weighted images makes diagnosis difficult, as in our case, leading to surgical exploration.     

A Case of Intraosseous Microcystic Meningioma Without a Mass Lesion

Both intraosseous and microcystic meningiomas are rare tumor types. We report the case of a 66-year-old woman with intraosseous microcystic meningioma without a mass lesion. She presented with a rare intraosseous microcystic meningioma manifesting as pain. Radiological examination revealed an osteolytic lesion in the right parietal bone. Magnetic resonance (MR) images showed iso- to hypointensity on T₁-weighted images and hyperintensity on T₂-weighted images corresponding to the lesion. T₁-weighted MR imaging with gadolinium enhancement better defined the marginal area. The inner table of the skull was disrupted prominently, and both sides of the outer table were eroded. There was fluid leakage during surgery but no obvious tumor mass. Histological examination revealed microcystic meningioma in the inner part of the defective bone. A macroscopic lesion was not found, because most of the tumor comprised microcysts, and their contents leaked out during the surgical procedure. Intraosseous microcystic meningioma may be considered as one of the differential diagnoses when the intraosseous tumor in the skull has fluid leakage and does not have a mass lesion during the surgery.     

Xanthogranulomatous pancreatitis mimicking a malignant cystic tumor of the pancreas: report of a case

Xanthogranulomatous pancreatitis (XGP) is a rare inflammatory disease of the pancreas. A correct diagnosis is usually made only after pathological examination. A 76-year-old man was referred to our hospital for investigation of erythroderma, muscle weakness, and weight loss. We suspected dermatomyositis as a paraneoplastic phenomenon and investigated accordingly. Computed tomography showed a cystic lesion encapsulated by a thick wall in the pancreatic body. On magnetic resonance imaging, the lesion had low intensity on the T1-weighted images and heterogeneously high intensity on the T2-weighted images. ¹⁸F-Fluorodeoxyglucose positron emission tomography showed abnormal uptake with a maximum standardized uptake value of 9.1. Based on these findings, we made a preoperative diagnosis of intraductal papillary-mucinous carcinoma and performed a distal pancreatectomy. Macroscopically, the cyst was surrounded by a yellow-tan mass with an unclear border, and was filled with hemorrhagic and necrotic tissue. Microscopically, the mass contained an aggregation of many foamy histiocytes, lymphocytes, and plasma cells. These microscopic findings were consistent with xanthogranulomatous inflammation, and the lesion was diagnosed as XGP. Although it is a rare benign pancreatic lesion, XGP should nevertheless be considered in the differential diagnosis of cystic lesions of the pancreas.     

Cystic cavernous angiomas

Cystic cavernous angiomas are rarely found in patients. We have reviewed 25 cases of cystic cavernous angiomas, including our case. The patients were predominantly women (15 women and 10 men). The patients’ ages ranged from 4 months to 75 years (mean age, 44.0 years). The most frequent symptoms were headache (32%) and cerebellar signs (32%), followed by papilledema (24%), hemiparesis (20%), and seizures (20%). The cystic cavernous angiomas were located in the supratentorial region in 16 (64%) cases, the cerebellopontine angle in 4 (16%) cases, and the cerebellum in 5 (20%) cases. Multiple cystic lesions were observed in only two cases (8%). The typical magnetic resonance images of these patients showed a mixed-intensity nodule on the T1- and T2-weighted images, iso- to high-intensity cysts on the T1-weighted images, and high-intensity cysts on the T2-weighted images. In some of the images, the nodules and cyst walls were enhanced. On the T2-weighted images, the periphery of the cyst showed low intensity. The approach involving total removal of the nodule, partial resection of the cyst, and drainage of the content of the cyst is considered a preferable strategy. Histologically, the nodule showed a network of thin-walled vascular channels lined by endothelium. Hemosiderin deposits and calcification were observed in some cases, and neural tissue was absent. The cyst wall was composed of neocapillary-containing fibrous tissue and showed a proliferation of inflammatory cells and hemosiderin deposits. The etiology of cyst formation remains unclear; however, recurrent hemorrhage from the sinusoids of the vascular malformation or from the neocapillary of the cyst wall and the osmotic transport of water into the cyst are thought to induce the growth of the cyst.     

Involuted intraosseous lipoma of the sacrum showing high signal intensity on T1-weighted magnetic resonance imaging (MRI)

Involuted intraosseous lipoma with extensive fat necrosis resulting in cyst formation (Milgram stage III) is distinguishable from lesions without necrosis (stage I) or lesions with focal fat necrosis (stage II), based on differences in signal intensity on magnetic resonance imaging (MRI). Fat tissue has a high signal intensity on both T1- and T2-weighted MR images, whereas the extensive fat necrosis that results in cyst formation shows high signal intensity on T2-weighted images and low intensity on T1-weighted images. We report a patient in whom an intraosseous lipoma with high signal intensity on both T1- and T2-weighted MRI was found to be extensively involuted on histopathologic examination. Intraosseous lipoma appears to undergo spontaneous involution. In some patients, therefore, surgical excision may not be necessary. A correct preoperative diagnosis should reduce the necessity for a biopsy or surgery. Although lesions classified as stage I or II are easily identified by MRI, those of stage III are difficult to diagnose preoperatively by this method. Received: May 12, 1998 / Accepted: November 7, 2000     

Cystic tumors of the pancreas. New clinical, radiologic, and pathologic observations in 67 patients.

Within a 12-year period we treated 67 patients (49 women, 18 men; mean age, 61 years) with cystic neoplasms of the pancreas, including 18 serous cystic adenomas, 15 benign mucinous cystic neoplasms, 27 mucinous cystadenocarcinomas, 3 papillary cystic tumors, 2 cystic islet cell tumors, and 2 cases of mucinous ductal ectasia. Mean tumor size was 6 cm (2 to 16 cm). In 39% the patients had no symptoms, and in 37% the lesions had been misdiagnosed as a pseudocyst. Computed tomography was useful for detection, for distinguishing the microcystic subgroup of serous cystadenoma, and for showing rim calcification (all 7 cases were malignant) but was not reliable for distinguishing neoplasm from pseudocyst, serous from mucinous tumors, or benign from malignant. Arteriography showed hypervascularity in 4 of 10 serous adenomas, 3 of 11 mucinous carcinomas, and 1 of 1 papillary cystic tumors. Endoscopic pancreatography showed no communication with the cyst cavity in 37 of 37 cases of cystic neoplasms but opacified the ectatic ducts in 2 of 2 cases of mucinous ductal ectasia. Stenosis or obstruction of the pancreatic duct indicated cancer. The tumor was resected by distal pancreatectomy in 25 patients, by proximal resection in 29, and by total pancreatectomy in one, with no operative deaths. Forty-four per cent of the tumors were malignant. In 10 cases the tumor was unresectable because of local extension or distant metastases, and those patients died at a mean of 4 months. Seventy-five per cent of those resected for cure are alive without evident recurrence. Because the epithelial lining of the tumor was partially (5% to 98%) absent in 40% to 72% of cases of the major tumor types, and the mucinous component comprised only about 65% of mucinous cystadenoma lining, misdiagnoses on frozen and even permanent sections were made. Mitoses and histologic solid growth correlated with malignancy. Neuroendocrine elements were seen in 87% of benign and 47% of malignant mucinous tumors. It is recommended that the terms macrocystic and microcystic be abandoned in favor of the histologic designations serous and mucinous. Incomplete examination of the cyst wall can be misleading, however. It is suggested that mucinous ductal ectasia be recognized separately from cystic tumors and that all of these lesions be resected, with the possible exception of asymptomatic confirmed serous cystadenomas.     

Synovial cyst of the transverse ligament of the atlas in a patient with os odontoideum and atlantoaxial instability

STUDY DESIGN: A case report and review of the literature. OBJECTIVE: To describe the diagnosis and successful treatment of a synovial cyst arising from the transverse ligament in a patient with os odontoideum and atlantoaxial instability. SUMMARY OF BACKGROUND DATA: Synovial cysts arising from the transverse ligament of the atlas are extremely rare. Development of a synovial cyst is thought to be attributable to degenerative changes of the C1-C2 facet joints or to microtrauma. Direct excision of the cyst is the only treatment cited in previous reports. METHODS: A synovial cyst arising from the transverse ligament of the atlas in a 45-year-old man with os odontoideum and atlantoaxial instability was treated surgically with posterior atlantoaxial fusion alone. The magnetic resonance images, surgical treatment, and related literature are reviewed. RESULTS: Preoperative magnetic resonance images of the cervical spine showed a large cystic mass located ventral to the cord arising at the level of the transverse ligament of the atlas: the mass was of low signal intensity on T1-weighted images, was of high signal intensity on T2-weighted images, and was enhanced marginally with gadolinium-DTPA on T1-weighted images. Spontaneous regression of the cyst was identified on the follow-up magnetic resonance images taken 3 months after C1-C2 posterior wiring and fusion. CONCLUSIONS: A patient with a synovial cyst arising at the C1-C2 junction ventrally at the level of the transverse ligament showed spontaneous regression of the lesion after C1-C2 posterior wiring and fusion.     

Case report of lumbar discal cyst

The authors describe a rare case of lumbar discal cyst which produced manifestations similar o lumbar disc herniation. A 33-year-old man, who had had a crick in the back 3 months previously, suffered from severe low back and right lower-extremity pain. The neurological examination showed the L5 radiculopathy through the positive straight leg-raising test, no motor weakness nor sensory disturbance with normal reflexes. Magnetic resonance imaging demonstrated an oval shaped extradural lesion with a low signal intensity on T1-weighted images and a high signal intensity on T2-weighted images. Additionally, the surrounding rim of the cyst was enhanced with the addition of Gd-DTPA. As we diagnosed a lumbar discal cyst with severe symptoms, the patient received emergent surgery. The symptom disappeared immediately after surgery. This case implies that early surgery for discal cyst may be an effective means to obtain release from symptoms.     

Carcinoma ex microcystic adenoma of the pancreas: a report of a novel form of malignancy in serous neoplasms

Serous cystic neoplasms of the pancreas are generally considered benign lesions. Malignant counterparts have been occasionally described, and the diagnosis of malignancy is based solely on the presence of synchronous or metachronous metastases to the lymph nodes or liver, direct tumor invasion into adjacent organs, or vascular invasion. However, these malignant serous cystic tumors are lined by benign-appearing glycogen-rich cuboidal cells, which have been morphologically indistinguishable from benign microcystic serous cystadenoma in all the cases reported so far. We report a unique case of microcystic serous cystadenoma giving rise to carcinoma with distinctive histologic features including signet ring-like cells and solid nests. We believe that this case represents the first case of a cytologically malignant neoplasm arising from a benign serous cystadenoma (carcinoma ex microcystic serous cystadenoma).     

Retrodental synovial cyst which disappeared after posterior C1-C2 fusion: A case report

Synovial cysts of the cervical spine are extremely rare. We describe an 8-year-old boy with atlantoaxial subluxation and hypoplasia of the dens. Magnetic resonance imaging showed a round lesion, posterior to the odontoid process. This mass was characterized by a low signal intensity on T1-weighted images, and high signal intensity on T2-weighted images. The retrodental synovial cyst disappeared after posterior atlantoaxial arthrodesis.     

Subtentorial cerebral nocardiosis in immunocompetent patients: CT and MR imaging findings

PurposeTo describe the clinical presentation and computed tomography (CT) and magnetic resonance imaging (MRI) appearances of subtentorial nocardia cerebral abscesses developing in immunocompetent patients.Patients and methodsThe clinical findings and the results of CT and MRI examinations of three immunocompetent patients with nocardiosis located initially only in the subtentorial region were studied. Three patients underwent CT examination and two patients had MRI.ResultsClinically, two patients had cerebellar syndrome and the third had meningism with fever. The diagnosis of nocardiosis was bacteriologically confirmed by demonstrating the organism in lumbar puncture fluid in one patient and by an aspiration biopsy of the abscess in the other two. Two of the patients improved under targeted antibiotic therapy whereas the third patient died. The main imaging features of the lesions were a multiloculated appearance with peripheral enhancement after intravenous administration of iodinated contrast material on CT and a multicystic appearance on MRI, with a peripheral hypointense rim on T2-weighted images, a relatively minor mass effect and a multiloculated appearance on gadolinium-chelate enhanced T1-weighted images.ConclusionThe clinical presentation of cerebral nocardiosis is relatively non-specific. A microcystic lesion surrounded by hypointensity on T2-weighted MR images with a multiloculated pattern after gadolinium chelate administration on T1-weighted MR images in association with a relatively minor mass effect should suggest this diagnosis even if the lesion is single and in the absence of immunosuppression.     

A case report of serous cystadenoma located in pancreatic tail]

Cystadenomas of the pancreas are relatively rare compared to pseudocysts. There are two types of cystadenoma of the pancreas; mucinous and serous. Serous cystadenomas of the pancreas are very rare. We experienced a serous cystadenoma located in pancreatic tail. The patient was male, forty-one years old, and was free from any subjective symptom. The pancreatic cyst was found by abdominal ultrasonography and was difficult to differentiate serous or mucinous by computed tomography or celiac angiography preoperatively. We performed distal pancreatectomy and the cyst was revealed to be serous cystadenoma pathologically.     

Colloid (enterogenous) cyst in the frontal lobe

A 60-year-old man presented with a left frontal mass lesion incidentally detected at a health check without apparent symptoms. Computed tomography revealed the lesion as homogeneous high density and magnetic resonance (MR) imaging showed the lesion as hyperintense on T(1)-weighted images, isointense on T(2)-weighted images, and hypointense on diffusion-weighted images. T(1)-weighted MR images with gadolinium showed no enhancement of the mass lesion. Cerebral angiography revealed an avascular area around the left frontal lesion. Total removal of the lesion was achieved through a craniotomy without complications. Histological, immunohistochemical, and electron microscopy examinations established the definite diagnosis of colloid cyst.     

胰腺浆液性微囊性腺瘤临床病理学观察

目的 探讨胰腺浆液性微囊性腺瘤(serous microcystic adenoma,SMA)的临床与病理学特点.方法 对12例SMA进行临床病理、特殊染色及免疫组化观察并随访.结果 ①临床:12例SMA中,男3例、女9例,35～70岁,平均51.5岁;7例因体检发现,5例因上腹不适或疼痛就诊;肿瘤直径2.0～13 cm,平均6.0 cm,切面均呈蜂窝状,囊内含清亮液体或灰红色液体.②镜下:瘤组织由多量小囊腔构成,囊壁内衬单层立方或扁平上皮,胞浆透亮,富含糖原,部分嗜酸,核小而圆,深染,大小一致,无明显异型性,核分裂像极少或无.③特殊染色:瘤细胞PAS(+),AB-PAS(-).④免疫组化:AEl/AE3及EMA(+),CEA、Vimentin、CgA、Syn、CD34、P53及S-100均(-).10例病人随访12～71个月,均未见复发.结论 SMA为胰腺罕见的肿瘤,临床上多无明显症状,依据其特有的病理组织学形态及免疫组化染色可明确诊断.其具体生物学行为有待进一步研究.