Recipient to donor conduction of atrial tachycardia following orthotopic heart transplantation

Postspinal headache is one of the most common complications of spinal anesthesia and has repeatedly led to controversy concerning needle size and configuration. In an in vitro investigation, we measured cerebrospinal fluid (CSF) leakage with Sprotte, Whitacre, Quincke, and Atraucan needles under physiological conditions in human dura. The puncture characteristics were examined under an electron microscope. The pencil-point needles show 2-3 times less leakage of CSF compared with the cutting Quincke needles of corresponding size. Between the Sprotte and the Whitacre needles, there were no significant differences. The least loss of CSF occurred with the 26-gauge Atraucan needle. Under the electron microscope, a sharply delineated, persistent perforation channel was shown with the Quincke needles, which may explain the high CSF loss. With pencil-point needles, which push the tissue apart bluntly, a large opening on the inside is found, with some tearing of the dura. However, in contrast to the cutting needles, a persistent perforation channel is not manifested. The 26-gauge Atraucan needle, which both cuts and pushes apart conically, shows a relatively discrete opening on the inside, with slight tears in the dura and arachnoidea but without a visible perforation channel. The results of our study show that larger needles (26-gauge Atraucan) that are easier to handle can lead to good and, in some cases even better, puncture results if they have characteristics of both the cutting and the pencil-point needles. IMPLICATIONS: We compared several brands of pencil-point and standard cutting spinal needles of varying sizes. All pencil-point needles had less cerebrospinal fluid leakage, the least loss occurring with 26-gauge Atraucan needles. Electron microscopic examination of the dura after puncture showed characteristic findings with each needle type. We conclude that the combined cutting and pencil-point characteristics seen in the Atraucan needle may have clinical advantages.     

Atraucan: a new needle for spinal anesthesia

BACKGROUND AND OBJECTIVES: Atraucan 26-gauge spinal needles have a tip designed to make a small linear cut (as opposed to a V-shaped cut) in the dura mater. The cut is shorter than the outside diameter of the needle and is dilated as the needle passes through the dura. The needle is used with a 20-gauge introducer. In vitro, it causes less leakage of cerebrospinal fluid than Quincke 26-gauge or Sprotte 24-gauge needles. This study was designed to test the ease of use and any damage caused to the needle tip during lumbar dural puncture. METHODS: This was a multicenter trial (six centers in five countries) involving 362 patients undergoing spinal anesthesia. A detailed questionnaire was filled in for every patient by the anesthesiologist. All the needles were returned to the factory and examined microscopically for damage. RESULTS: Lumbar dural puncture was successful in all but one patient. Spinal anesthesia was satisfactory for the planned surgery in 97%. Microscopy of the needle tips showed only a minor degree (0.01-0.19 mm) of bending in 14%, and none of the tips had a "hook." Postdural puncture headache (PDPH) occurred in nine patients (2.5%), all but one of whom (a 15-year-old male) were females under 55 years of age. CONCLUSIONS: The Atraucan needle is easy to use and has a high success rate in identifying the subarachnoid space. Lumbar dural puncture causes minimal damage to the tip. The incidence of PDPH is low, but a larger comparative study needs to be performed.     

Neurologic complications after placement of cerebrospinal fluid drainage catheters and needles in anesthetized patients: implications for regional anesthesia. Mayo Perioperative Outcomes Group

Subarachnoid or epidural needle placement in an anesthetized patient is controversial because general anesthesia and muscle relaxation may mask neural trauma. However, placement of a needle or catheter in the subarachnoid space for the purpose of cerebral spinal fluid (CSF) drainage is frequently performed in anesthetized patients undergoing neurosurgery. The records from 530 consecutive transsphenoidal surgeries performed with lumbar CSF drainage were reviewed to determine the types of neurologic complications attributable to spinal drainage and their rates of occurrence. All patients were anesthetized during CSF drain placement. A 19-gauge malleable needle was placed in 473 (89%) patients. Subarachnoid catheters (20- or 16-gauge catheters placed via 18- or 14-gauge epidural needles, respectively) were placed in 17 (3%) patients. In 40 (8%) patients, the type of drain was unspecified. No new neurologic deficits attributable to spinal drain insertion were detected in the immediate postoperative period or within 1 yr of surgery. Thirteen patients developed postdural puncture headache (2.5%, exact 95% confidence interval 1.3%-4.2%); seven required epidural blood patch (1.3%, 0.5%-2.7%). The low incidence (0%, 0.0%-0.7%) of neurologic injury from spinal drain insertion in anesthetized patients from this study is similar to the incidence of neurologic complications historically reported for both CSF drain insertion and spinal anesthesia. Implications: The performance of regional anesthesia in an anesthetized patient is controversial due to the possibility of unrecognized nerve injury. We report no cases of nerve injury caused by the placement of cerebrospinal fluid drainage needles and catheters in 530 anesthetized patients undergoing neurosurgery.     

Electron microscopy of the lesions produced in the human dura mater by Quincke beveled and Whitacre needles

INTRODUCTION: Comparisons of Quincke needles and non traumatic "pencil point" needles in recent years have reported lower rates of post dural puncture headache using the later type. Our new understanding of the morphology of the human dura mater motivated us to study dural lesions caused by the Whitacre 25 G and Quincke 26 G needles, using scanning electron microscopy with the aim of determining whether there is an anatomic basis for the different outcomes. METHOD: The dura mater from three fresh cadavers of individuals aged 65, 70 and 72 years were punctured 40 times at an angle of 90 degrees each time. The Whitacre 25 G needle was used for 20 punctures and the Quincke 26 G needle was used for the other 20. Half the punctures were performed with the bevel in the parallel alignment and the other half with the bevel perpendicular to the spinal column. Fifteen min after causing the punctures, specimens were fixed in solutions of glutaraldehyde phosphate buffer and dehydrated in acetone. After critical point removal of the acetone, after the specimens were treated with carbon and metallized with gold. The lesions were examined externally and internally and expressed as the ratio of area of lesion to diameter of the needle that had caused them. RESULTS: Whitacre needle: each lesion consisted in the superimposition of multiple damaged layers that started to close individually. After 15 min the outermost layers were 90% closed and the innermost ones had closed entirely. Layers in the arachnoid surface of the dura mater had closed from 86 to 88%, while deeper layers in the thick part had closed 97 to 98%. Quincke needle: lesions were V-shaped or half-moon shaped, much like the opening formed by a can opener, on both the external and internal surfaces. Alignment of the bevel of the needle parallel to the spinal column did not lead to a different shape of puncture. After 15 min the lesions had closed 94 to 95% on the epidural surface and 95 to 96% on the arachnoid side, a difference attributable to the retraction of the arachnoid layers over the spinal column. CONCLUSION: Non traumatic beveled dural needles, termed "pencil point needles", only partially separate dural fibers, and lesions caused by these needles develop in a more complex way. The Quincke 26G needle produced a puncture that is morphologically different from that caused by the Whitacre 25G needle, although lesions produced by both types close more than 94% after 15 min. We believe the size of the lesion caused by these needles does not explain the difference in post dural puncture headache due to loss of spinal fluid.     

Postmyelography headache: a review

The author reviews the topic of postdural puncture headache (PDPH) so radiologists can better understand, prevent, and treat this common complication of myelography. PDPH, a postural headache relieved by lying supine, occurs after 36.0%-58.2% of myelographic procedures performed with 22-gauge Quincke needles. It begins within 3 days and lasts 3-5 days. Thin, young women are more likely to develop PDPH. Smaller gauge needles, blunt-tip needles, a paramedian approach, and parallel orientation of a bevel needle are associated with lower PDPH rates. Intravenous hydration, no removal of cerebrospinal fluid, experience of the myelographer, and inpatient status have been inconsistently associated with lower PDPH rates. Treatment is supportive with bed rest. Oral or intravenous methylxanthine agents may be given for more severe PDPH. An epidural blood patch, although rarely needed, is very effective.     

Testing an implantable intraspinal drug delivery device in the ewe

OBJECTIVE: The authors report the use of multiple implanted intraspinal port and catheter systems per test animal to study the in vivo functional characteristics and reliability of a new implantable spinal drug delivery port system. METHODS: Four ewes were each implanted with two epidural and one subarachnoid silicone elastomer catheters at the lumbar level. Each catheter was connected in series to one of three Therex filtered spinal delivery ports implanted subcutaneously in a similar grid pattern in each ewe to facilitate percutaneous identification. Saline (2 ml) was injected 3 times weekly in each port. The ease of injection and behavioral responses were recorded for 207-213 days of implantation until sacrifice/necropsy. RESULTS: All ports functioned reliably during the study. However, injection through two of the four subarachnoid catheters resulted in behavioral withdrawal responses intermittently. This behavioral pattern was much less common after epidural port injections. All four subarachnoid and four of eight epidural port and catheter systems were tested with local anesthetic just before sacrifice. Motor block was observed in three of four subarachnoid and three of four epidural port and catheter systems tested. Integrity of the other four epidural ports was tested by injection of methylene blue at sacrifice. This dye did not distribute in the epidural space in one of the latter four epidural ports (not local anesthetic tested) because of a concentric fibrotic reaction about the catheter. Similar fibrotic reactions surrounded the catheters that failed a functional test with local anesthetic. CONCLUSIONS: The implantable intraspinal port system tested functions reliably under repetitive percutaneous access. However, filtering such ports, though desirable to prevent entry of debris into the spinal canal, did not eliminate pericatheter chronic subarachnoid and epidural reaction. The number of test animals required to test 12 ports chronically was reduced by two-thirds without undue trauma to the individual test subject. Chronic percutaneous injection of an implanted subarachnoid system is feasible but may be associated with behavioral effects similar to that seen with chronic epidural systems. Fibrosis around chronic silicone catheters limited functional utility in one-fourth of the implanted test systems. Further study of the potential reactivity of chronic epidural and subarachnoid catheters is indicated.     

Subarachnoid anesthesia with minimal doses of lidocaine in ambulatory arthroscopic surgery of the knee

The objective is demonstrate that subarachnoid anesthesia with 2% isobaric lidocaine at low doses (0.5 mg/kg) is safe and effective for outpatient arthroscopic surgery of the knee. This was a prospective study of 150 ASA I-III patients undergoing arthroscopic knee surgery as outpatients under subarachnoid anesthesia. With no prior vascular filling, we provided blockade by administering 2% isobaric lidocaine at a dose of 0.5 mg/kg through a Sprotte 25G needle without vasoconstrictor. We assessed effectiveness and degree of sensory-motor blockade, cardiovascular repercussions, recovery time (until reversal of blockade, ambulation, micturition and discharge) as well as side effects observed. The mean dose of lidocaine used was 33.44 +/- 4.16 mg. The sensory-motor blockade achieved provided optimum conditions for prevention of ischemia and the practice of the surgical procedure in all cases. Surgery lasted a mean 38 +/- 10 min. Hemodynamic changes were not clinically significant and no patients additional fluids, atropine or vasopressors. Time from start of blockade until ambulation, micturition and discharge from the recovery unit were 123 +/- 8.3, 175 +/- 12.4 and 194 +/- 13.4 min, respectively. Micturition was spontaneous in all cases. Complications recorded were cephalea and backache. In conclusion, subarachnoid anesthesia at low doses of 2% isobaric lidocaine provides excellent conditions for practicing arthroscopic surgery of the knee on outpatients, with minimum side effects.     

Erythrocyte Na/K ATPase activity and diabetes: relationship with C-peptide level

The purpose of this study is to clarify the volume effect of epidural saline injection 20 min after spinal anesthesia. Thirty patients undergoing combined spinal and epidural anesthesia for orthopedic surgery were randomly divided into two groups: a control group (n = 15) and a saline group (n = 15). In the control group, 2% lidocaine 3 ml with 0.4% tetracaine was injected into the subarachnoid space from L 4-5 interspace using Durasafe (Becton Dickinson, USA) and saline was not injected into the epidural space. In the saline group, saline 10 ml was injected through an epidural catheter 20 min after spinal anesthesia. The levels of analgesia 20 min after spinal anesthesia were not significantly different between the groups. However, the levels of analgesia 3, 5, 10, 40 and 100 min after epidural saline injection in the saline group were significantly higher than those in the control group (P < 0.05). The highest analgesic level was obtained 10 min after epidural saline injection and reached to T 4.3 +/- 1.1. In conclusion, epidural saline injection increases the analgesic level 20 min after spinal anesthesia because of the volume effect.     

Pain in the lower extremities after subarachnoid block with lidocaine

Subarachnoid block is a widely practiced anesthetic technique. With the availability of small-diameter needles and the rises in out-patient surgery, the number of procedures performed with subarachnoid block and short-term local anesthesia have increased. We report two cases of bilateral pain in the lower extremities appearing 20-24 h after intradural anesthesia with 2% hyperbaric lidocaine. We analyze the factors that might have triggered this complication and compare the two patients with 14 others described in the literature. Three points in common were found: the use of hyperbaric lidocaine, administration of the agent through small gauge needles and the performance of out-patient surgery.     

Safety of spinal and epidural anesthesia in parturients with chorioamnionitis

BACKGROUND AND OBJECTIVES: The safety of spinal and epidural anesthesia in patients with chorioamnionitis was explored. METHODS: A retrospective study was made of the charts of 517 parturients who had received epidural anesthesia and 14 who had received spinal anesthesia before delivery and whose placentas had subsequently been found to be positive for chorioamnionitis. RESULTS: Of the 146 blood culture results that were reported, 13 were positive. Of these 13 blood cultures, 5 had been drawn within 6 hours after placement of the epidural block, and four of the five bacteremic patients did not receive antibiotics until after the regional anesthetic was administered. One quarter (11/45) of the patients who were febrile and three quarters (174/229) of those who had leukocytosis before their block received no antibiotics before the block was placed. After the epidural block was performed, the catheter was left in place for over 24 hours in 18% (46/260) of the women who spiked a fever and in 14% (18/130) of those who exhibited leukocytosis during that period. There was no report of an epidural or spinal abscess or of meningitis in any of the women in the study. CONCLUSION: Conduction anesthesia may be safe in parturients with chorioamnionitis without prior antibiotic therapy.     

What is your diagnosis? Leiomyosarcoma of the cecum

Epidural hematoma is a rare but serious neurological complication of epidural anesthesia. We report the case of a 61-year-old man with squamous cell carcinoma of the lung who suffered an epidural hematoma after undergoing right double lobectomy. Before anesthetic induction an epidural catheter was inserted to the D5-D6 space for postoperative analgesia. Surgery was without noteworthy events and the patient was extubated in the operating room; 5,000 IU of low molecular weight heparin was injected subcutaneously every 24 hours and 5 mg of methadone was provided by epidural catheter every 8 hours. After removal of the catheter three days after surgery, lumbar back pain and hypoesthesia, and weakness in both legs appeared. Epidural hematoma was suspected and treatment with 30 mg.kg-1 of methylprednisolone i.v. was started. Nuclear magnetic resonance imaging of the lumbar spine confirmed the presence of a hematoma at D6-D8. Neurologic symptoms improved in the following hours and additional surgery was not required. The patient was released without neurological symptoms 10 days after lung surgery. We discuss the prevalence, etiology and treatment of epidural hematoma related to epidural anesthesia.     

Spinal epidural abscess associated with epidural anesthesia: gadolinium-enhanced magnetic resonance imaging and its usefulness in diagnosis and treatment

A case of spinal epidural abscess following epidural anesthesia is described. Gadolinium-enhanced magnetic resonance images were essential in diagnosis of the abscess without frank pus formation, in defining the extension of the infection, and in assessing the therapeutic effect. The patient was successfully treated non-operatively before neurological symptoms developed and full recovery was achieved.     

Reattempting failed external cephalic version under epidural anesthesia

OBJECTIVES: We hypothesize that the success rate of external cephalic version may be increased by performing a repeat attempt with the patient under epidural anesthesia. STUDY DESIGN: One hundred eight women with term singleton pregnancies in breech presentation underwent attempted external version. When external version failed, we offered them the option of a later attempt under epidural anesthesia. All fetuses who remained in breech position were delivered by elective cesarean section. RESULTS: Fifty (60%) of the 83 attempted external versions performed without anesthesia were successful. Seventeen of the 33 women whose versions were unsuccessful underwent elective cesarean delivery, and 16 elected to undergo repeat version attempts under epidural. Nine (56%) of these 16 procedures were successful, and 7 of these 9 women were delivered vaginally. The overall success rate was 71%, similar to the success rate of versions attempted on 25 women under epidural anesthesia. CONCLUSIONS: When an attempted external version fails, a repeat attempt under epidural anesthesia will usually be successful, resulting in a lower cesarean delivery rate.     

Intraoperative ultrasound in lumbar intervertebral disk displacement

Intraoperative ultrasound of the spine has been used in neurosurgery (tumours) and traumatology (reposition of fractured vertebral bodies fragments). AIM: To describe initial experiences with this method and to document the opportunities and problems. METHOD: 24 nucleotomies were documented and evaluated. Sonography was performed using a 7.5 MHz sector probe and a typical surgical approach. RESULTS: In 21 of 24 cases, imaging of intraspinal structures was possible. The complete extraction of the herniated disk could be documented. In 3 cases the examination failed because the probe was too large to be pushed down between the spinous processes and the wound retractor to the operative site. CONCLUSIONS: Intraoperative sonography can be used easily as a routine method for exploration of the spinal canal. Technical innovations in the probes would make the method even more feasible.     

Prospects of the use of caudal epidural anesthesia

Caudal epidural anesthesia for interventions on the lower limbs and pelvic organs was used in 525 patients. A specific feature of the method is use of hypoosmolic local anesthetic solution (osmolality 260 mosmol/kg) containing lidocaine, 0.9% sodium chloride, and distilled water. Pathologic studies showed that in adult patients, at least 40 ml anesthetic should be injected into the caudal canal for adequate blocking. During surgery, caudal epidural anesthesia reliably protected from surgical trauma without side effects for respiration and circulation. The duration of analgesic effect was 3 +/- 0.5 h and even longer, if local anesthesia was potentiated with sedative drugs. No complications were observed, failures occurred in 5.2% cases. The method is simple and reliable and is recommended for practice.     

Carcinoma of the pancreas

A rare tumour of a prepubertal child, an epidermoid cyst, was excised with testicular preservation. Childhood testicular tumours are usually benign. Although epidermoid cysts of the testis may have teratomatous component, testicular teratomas are generally benign in the prepubertal child. For these reasons testis sparing surgery seems applicable in childhood epidermoid cysts.     

Intraspinal epidural sarcoidosis: case report

OBJECTIVE AND IMPORTANCE: A rare case of lumbar intraspinal epidural sarcoidosis is identified. The rarity of this condition and its clinical presentation are stressed. CLINICAL PRESENTATION: A young Caucasian man presented with the progressive onset of cauda equina syndrome as a result of an expanding mass in the lumbar epidural space compromising the lumbar dural tube from L1 to S1. The patient presented with motor, sensory, and sphincteric dysfunction as a result of this large intraspinal epidural mass. No evidence of systemic illness was noted concomitant with the patient's onset of neurological symptomatology. The patient underwent surgical extirpation of a lumbar intraspinal epidural mass, which was identified histopathologically as sarcoid granuloma. The postoperative work-up included the identification of a mediastinal adenopathy, which was subsequently biopsied and confirmed the diagnosis of sarcoid disease. The patient was treated postoperatively with oral prednisone over a 4-month period. At 7 months postoperatively, the patient had regained gainful employment, the results of his neurological examination were normal, and he was pain-free. INTERVENTION: The patient underwent a multilevel bilateral lumbar laminectomy with facet preservation, extending from L1 to S1, allowing for a gross total removal of the epidural mass. Postoperative oral prednisone was administered as adjuvant therapy for the treatment of multisystem sarcoid disease. CONCLUSION: Aggressive surgical management involving the removal of an extensive epidural mass of the lumbar canal, which was diagnosed as sarcoid disease, coupled with the adjuvant use of oral prednisone has resulted in an excellent outcome for the patient. The results of his clinical examination are now normal, and postoperative radiological imaging reveals no evidence of recurrent or residual disease in the lumbar epidural space. In the unusual case of intraspinal epidural sarcoidosis, the surgical resection of accessible intraspinal epidural masses is recommended, as is the use of oral prednisone postoperatively.     

Invasive squamous cell carcinoma arising from asymptomatic choristomatous cysts of the orbit. Two cases and a review of the literature

BACKGROUND: Epithelial choristomatous cysts are common orbital lesions, the most frequent of which are dermoid or epidermoid tumors. Massive enlargement or extraorbital extension of these benign lesions may occur. Malignant transformation of the epithelial lining of epidermoid cysts is rarely reported. METHODS: Two patients are presented in whom the epithelial lining of a previously asymptomatic choristomatous cyst of the orbit underwent malignant transformation to produce invasive squamous cell carcinoma. The unusual origin and clinical presentation of the lesions caused a delay in the diagnosis and therapy in both patients. Metastatic workup was negative in both patients, who underwent resection of their tumors via orbital exenteration with craniofacial resection. Reported cases of malignant transformation in analogous choristomatous cysts elsewhere in the cranium are reviewed. RESULTS: One patient is alive and well without recurrent disease 40 months postoperatively. The second patient died of a pulmonary embolus 2 months postoperatively. Autopsy showed no residual tumor. Overall, only 3 of 18 reported patients with epidermoid choristoma of the head and orbit with malignant transformation were alive when reported. CONCLUSIONS: Malignant squamous metaplasia is believed to be a rare complication of orbital dermoid or epidermoid cysts, with only two previously reported cases. However, malignant transformation is relatively frequent in analogous epidermoid cysts found elsewhere in the cranial vault, especially after incomplete excision. These reports encourage the complete removal of epithelial choristomas of the orbit.     

Epidural anesthesia impairs both central and peripheral thermoregulatory control during general anesthesia

BACKGROUND: The authors tested the hypotheses that: (1) the vasoconstriction threshold during combined epidural/general anesthesia is less than that during general anesthesia alone; and (2) after vasoconstriction, core cooling rates during combined epidural/general anesthesia are greater than those during general anesthesia alone. Vasoconstriction thresholds and heat balance were evaluated under controlled circumstances in volunteers, whereas the clinical importance of intraoperative thermoregulatory vasoconstriction was evaluated in patients. METHODS: Five volunteers were each evaluated twice. On one of the randomly ordered days, epidural anesthesia (approximately T9 dermatomal level) was induced and maintained with 2-chloroprocaine. On both study days, general anesthesia was induced and maintained with isoflurane (0.7% end-tidal concentration), and core hypothermia was induced by surface cooling and continued for at least 1 h after fingertip vasoconstriction was observed. Patients undergoing colorectal surgery were randomly assigned to combined epidural/enflurane anesthesia (n = 13) or enflurane alone (n = 13). In appropriate patients, epidural anesthesia was maintained by an infusion of bupivacaine. The core temperature that triggered fingertip vasoconstriction identified the threshold. RESULTS: In the volunteers, the vasoconstriction threshold was 36.0 +/- 0.2 degrees C during isoflurane anesthesia alone, but significantly less, 35.1 +/- 0.7 degrees C, during combined epidural/isoflurane anesthesia. Cutaneous heat loss and the rates of core cooling were similar 30 min before vasoconstriction with and without epidural anesthesia. In the 30 min after vasoconstriction, heat loss decreased 33 +/- 13 W when the volunteers were given isoflurane alone, but only 8 +/- 16 W during combined epidural/isoflurane anesthesia. Similarly, the core cooling rates in the 30 min after vasoconstriction were significantly greater during combined epidural/isoflurane anesthesia (0.8 +/- 0.2 degrees C/h) than during isoflurane alone (0.2 +/- 0.1 degrees C/h). In the patients, end-tidal enflurane concentrations were slightly, but significantly, less in the patients given combined epidural/enflurane anesthesia (0.6 +/- 0.2% vs. 0.8 +/- 0.2%). Nonetheless, the vasoconstriction threshold was 34.5 +/- 0.6 degrees C in the epidural/enflurane group, which was significantly less than that in the other patients, 35.6 +/- 0.8 degrees C. When the study ended after 3 h of anesthesia, patients given combined epidural/enflurane anesthesia were 1.2 degrees C more hypothermic than those given general anesthesia alone. The rate of core cooling during the last hour of the study was 0.4 +/- 0.2 degrees C/h during combined epidural/enflurane anesthesia, but only 0.1 +/- 0.3 degrees C/h during enflurane alone. CONCLUSIONS: These data indicate that epidural anesthesia reduces the vasoconstriction threshold during general anesthesia. Furthermore, the markedly reduced rate of core cooling during general anesthesia alone illustrates the importance of leg vasoconstriction in maintaining core temperature.     

Computed tomography of intracranial epidermoid tumours with special reference to atypical features

Intracranial intradural epidermoid tumours have been known to show characteristic CT features consisting of non-enhancing lucent lesions with sharply defined margins that are often irregular and scalloped. Since the epidermoid tumours are benign, potentially curable lesions, it should be also noted that they may occasionally show atypical CT features such as dense lesion, definite marginal enhancement following contrast medium injection, or tumour associated with large, heavy calcifications. Four such atypical cases are reported, and the literature is reviewed.