Unusual presentation of more common disease/injury
CASE REPORT
A rare case of racemose neurocysticercosis of the posterior fossa Lakshmikanth Halegubbi Karegowda,1 Poonam Mohan Shenoy,1 Koteshwara Prakashini,1 Gauri Karur2 1
Department of Radiology, Kasturba Medical College, Manipal, Karnataka, India 2 Department of Radiodiagnosis, Kasturba Medical College, Udupi, Karnataka, India Correspondence to Dr Poonam Mohan Shenoy, [email protected] Accepted 3 May 2014
To cite: Karegowda LH, Shenoy PM, Prakashini K, et al. BMJ Case Rep Published online: [please include Day Month Year] doi:10.1136/bcr-2014203955
SUMMARY A 43-year-old man presented with a 3 month history of headache, vertigo and swaying while walking. MRI of the brain showed cystic lesions involving the cerebellopontine angle cisterns, the right perimedullary cistern, the fourth ventricle and bilateral foramen of Luschka with resultant obstruction to cerebrospinal fluid outflow and hydrocephalus. The patient underwent right retromastoid craniotomy with endoscopic third ventriculostomy for cyst excision. The postoperative period was uneventful and he was able to carry out routine activities within a month. This case report
stresses on the clinical importance, unique characteristics and imaging features of racemose neurocysticercosis.
BACKGROUND Neurocysticercosis is the most common parasitic disease of the central nervous system in humans and is commonly seen in less developed countries. However, due to immigration of people from endemic areas, the disease is also increasingly being reported in more developed countries.1
Figure 1 (A) Axial T1, (B) axial T2, (C) coronal T2 and (D) axial T2 sequences of the brain. (A) Lesions in the bilateral foramen of Luschka and the right perimedullary cistern (B) and (C) Lesions in the right cerebellopontine angle cistern and the fourth ventricle. These images show cystic nature of the lesions which is comparable to cerebrospinal fluid (CSF) signal intensity. There is mass effect in the form of compression of the right middle cerebellar peduncle, pons (B and C) and the medulla (A). (D) Acute hydrocephalus with periventricular seepage of CSF secondary to obstruction to CSF outflow.
Karegowda LH, et al. BMJ Case Rep 2014. doi:10.1136/bcr-2014-203955
1
Unusual presentation of more common disease/injury Figure 2 Axial FIESTA (fast imaging with steady state acquisition) from caudal (A) to cranial (B) direction. These images show the clearly cystic nature of the lesions. (C) The involvement of the left cerebellopontine angle cistern with multiple hypointense walls/membranes within. (D) Cysts within the dilated fourth ventricle with membranes/walls.
The racemose variety of neurocysticercosis has an infrequent occurrence and is regarded as the most serious manifestation of neurocysticercosis as it can lead to sudden death by causing acute hydrocephalus. Hence, it is important to be familiar with its clinical manifestations and imaging appearances. Symptoms of the disease are usually secondary to inflammatory response, mass effect and hydrocephalus secondary to obstruction of the cerebrospinal fluid (CSF) pathway.2 With regard to radiological investigations, it is often difficult to diagnose this condition on CT as it may only show secondary signs such as mass effect, asymmetry
of ventricles or enlargement of cisterns without clear delineation of the cyst walls; hence, MRI forms a more specific investigation. In the present case, multiple cysticerci in the vesicular stage were seen in the cerebellopontine angle cisterns, the right perimedullary cistern, both foramen of Luschka and within the fourth ventricle causing significant mass effect and hydrocephalus.
Figure 3 Diffusion weighted images (A and B). No restriction of diffusion within the lesions in the right perimedullary cistern.
Figure 4 (A) Axial and (B) coronal postcontrast images. No enhancement of the wall of the lesions seen.
2
CASE PRESENTATION A 43-year-old man presented with a 3 month history of headache, vertigo and swaying while walking. There was no history
Karegowda LH, et al. BMJ Case Rep 2014. doi:10.1136/bcr-2014-203955
Unusual presentation of more common disease/injury
Figure 5 Histopathological section showing cysticercus larvae thrown in folds lined by pale eosinophilic membrane with numerous small cystic spaces. of vomiting or nausea. There was no history of seizures or altered behaviour. He was non-hypertensive, non-diabetic and had no significant past or family history. On clinical examination the patient was conscious and oriented. Neurological examination was positive for right cerebellar signs with intact higher mental functions and no cranial nerve deficits. Precontrast MRI revealed cystic lesions involving the right cerebellopontine angle cistern, the right perimedullary cistern, both foramen of Luschka and the fourth ventricle. The lesions were of CSF signal intensity on T1 and T2 sequences (figure 1)
and showed multiple thin hypointense septations which represent the walls/membranes of the cysticerci. These cyst walls/ membranes were best delineated on 3D FIESTA (threedimensional fast imaging with steady state acquisition) sequence (figure 2). Significant mass effect was noted in the form of compression of the right middle cerebellar peduncle and brainstem with obstruction to CSF outflow leading to hydrocephalus (figures 1 and 2). Diffusion-weighted imaging sequences showed no diffusion restriction (figure 3). Postcontrast sequence showed no significant enhancement of the walls of the cysticerci (figure 4). No obvious scolex was visualised and there was no abnormal meningeal enhancement. Serum and CSF ELISA tests for cysticercosis were positive. The patient underwent right retromastoid craniotomy with endoscopic third ventriculostomy under general anaesthesia for cyst excision. Gross specimen consisted of flattened glistening grey–white cystic lesions with smooth inner walls. Histopathology showed multiple cysticercus larvae thrown in folds lined by pale eosinophilic membrane with numerous small cystic spaces (figure 5). The patient received antihelminthic medication ( praziquental) after the surgery. He developed CSF leak from the wound site in the immediate postoperative period which was sutured with 2-0 ethilon and controlled successfully. The patient’s symptoms started to improve gradually and he was able to carry on his day-to-day activities normally by the end of 1 month. Follow-up CT of the brain (figure 6) showed significant decrease in the degree of hydrocephalus with complete removal of cysts.
Figure 6 Follow-up axial CT images after the surgery. (A) Right retromastoid craniotomy defect. (B–D) Complete removal of the cysts with normal-sized fourth ventricle.
Karegowda LH, et al. BMJ Case Rep 2014. doi:10.1136/bcr-2014-203955
3
Unusual presentation of more common disease/injury DISCUSSION Cysticercosis is a zoonosis caused by Taenia solium which most frequently involves the intracranial compartment (60–90% of the patients).3 The brain parenchyma is commonly affected by neurocysticercosis where it typically presents as a focal lesion with surrounding oedema at the grey–white matter interface which later calcifies. The ventricular system and the subarachnoid spaces may rarely be affected by the parasite and this form is known as racemose cysticercosis.4 The parasite usually shows various stages of evolution within the brain parenchyma, namely, live (vesicular), dying (colloidal vesicular and granular nodular) and dead (calcified nodular) stages. However, within the extra-axial space, the cysts are different from the parenchymal cysts as they exhibit abnormal large growth of the cystic membrane and remain in the vesicular stage with absent temporal degenerative changes. Also, majority of the extra-axial cysts show no scolex.2 4 5
MRI is the investigation of choice in diagnosing the condition due to its superior contrast resolution and direct multiplanar capability. In the present case, the lesions involved the CP angle cisterns, the right perimedullary cistern, both foramen of Luschka and the fourth ventricle. The walls of the cyst were well depicted on 3D FIESTA sequences as noted by other authors.6 Scolex, however, was not visualised in the present case even with FIESTA. The racemose variety can obstruct the ventricles or CSF outflow tracts either by direct mechanical obliteration or due to ependymitis leading to scarring. This could result in acute hydrocephalus and sudden death, mandating an early diagnosis and surgical intervention.7 In our case, the lesions were causing obstruction of the fourth ventricle and both foramen of Luschka resulting in acute hydrocephalus, which was treated promptly with surgical intervention leading to successful postoperative recovery of the patient. Acknowledgements Dr Manna Valiathan, Professor and Dr Swati Gupta, Postgraduate, Department of Pathology, KMC, Manipal. Competing interests None.
Learning points
Patient consent Obtained. Provenance and peer review Not commissioned; externally peer reviewed.
▸ Although uncommon, racemose cysticercosis is the most serious manifestation of cysticercosis as it can lead to sudden death due to acute hydrocephalus, and hence mandates an early diagnosis and surgical intervention. ▸ This form is different from the parenchymal cysts as they exhibit abnormal large growth of the cystic membrane and remain in the vesicular stage with absent temporal degenerative changes. ▸ MRI is the investigation of choice as CT often fails to delineate the cysts. ▸ 3D FIESTA (three-dimensional fast imaging with steady state acquisition) is an important advanced MRI sequence helpful in delineating the cyst walls/membranes.
REFERENCES 1 2 3 4 5 6 7
White AC Jr. Neurocysticercosis: updates on epidemiology, pathogenesis, diagnosis, and management. Annu Rev Med 2000;51:187–206. Kim SW, Kim MK, Oh SM, et al. Racemose cysticercosis in the cerebellar hemisphere. J Korean Neurosurg Soc 2010;48:59–61. Osborn AG. Diagnostic neuroradiology. 1st edn. Missouri: Mosby Year Book Inc, 1994:709–12. Mittal P, Mittal G. Intraventricular and subarachnoid racemose cysticercosis. Trop Parasitol 2011;1:111–12. Rahalkar MD, Shetty DD, Kelkar AB, et al. The many faces of cysticercosis. Clin Radiol 2000;55:668–74. Hingwala D, Chatterjee S, Kesavadas C, et al. Applications of 3D CISS sequence for problem solving in neuroimaging. Ind J Radiol 2011;21:90–7. Takayanagui OM, Odashima NS. Clinical aspects of neurocysticercosis. Parasitol Int 2006;55:S111–15.
Copyright 2014 BMJ Publishing Group. All rights reserved. For permission to reuse any of this content visit http://group.bmj.com/group/rights-licensing/permissions. BMJ Case Report Fellows may re-use this article for personal use and teaching without any further permission. Become a Fellow of BMJ Case Reports today and you can: ▸ Submit as many cases as you like ▸ Enjoy fast sympathetic peer review and rapid publication of accepted articles ▸ Access all the published articles ▸ Re-use any of the published material for personal use and teaching without further permission For information on Institutional Fellowships contact [email protected] Visit casereports.bmj.com for more articles like this and to become a Fellow
4
Karegowda LH, et al. BMJ Case Rep 2014. doi:10.1136/bcr-2014-203955
CASE REPORT
A rare case of racemose neurocysticercosis of the posterior fossa Lakshmikanth Halegubbi Karegowda,1 Poonam Mohan Shenoy,1 Koteshwara Prakashini,1 Gauri Karur2 1
Department of Radiology, Kasturba Medical College, Manipal, Karnataka, India 2 Department of Radiodiagnosis, Kasturba Medical College, Udupi, Karnataka, India Correspondence to Dr Poonam Mohan Shenoy, [email protected] Accepted 3 May 2014
To cite: Karegowda LH, Shenoy PM, Prakashini K, et al. BMJ Case Rep Published online: [please include Day Month Year] doi:10.1136/bcr-2014203955
SUMMARY A 43-year-old man presented with a 3 month history of headache, vertigo and swaying while walking. MRI of the brain showed cystic lesions involving the cerebellopontine angle cisterns, the right perimedullary cistern, the fourth ventricle and bilateral foramen of Luschka with resultant obstruction to cerebrospinal fluid outflow and hydrocephalus. The patient underwent right retromastoid craniotomy with endoscopic third ventriculostomy for cyst excision. The postoperative period was uneventful and he was able to carry out routine activities within a month. This case report
stresses on the clinical importance, unique characteristics and imaging features of racemose neurocysticercosis.
BACKGROUND Neurocysticercosis is the most common parasitic disease of the central nervous system in humans and is commonly seen in less developed countries. However, due to immigration of people from endemic areas, the disease is also increasingly being reported in more developed countries.1
Figure 1 (A) Axial T1, (B) axial T2, (C) coronal T2 and (D) axial T2 sequences of the brain. (A) Lesions in the bilateral foramen of Luschka and the right perimedullary cistern (B) and (C) Lesions in the right cerebellopontine angle cistern and the fourth ventricle. These images show cystic nature of the lesions which is comparable to cerebrospinal fluid (CSF) signal intensity. There is mass effect in the form of compression of the right middle cerebellar peduncle, pons (B and C) and the medulla (A). (D) Acute hydrocephalus with periventricular seepage of CSF secondary to obstruction to CSF outflow.
Karegowda LH, et al. BMJ Case Rep 2014. doi:10.1136/bcr-2014-203955
1
Unusual presentation of more common disease/injury Figure 2 Axial FIESTA (fast imaging with steady state acquisition) from caudal (A) to cranial (B) direction. These images show the clearly cystic nature of the lesions. (C) The involvement of the left cerebellopontine angle cistern with multiple hypointense walls/membranes within. (D) Cysts within the dilated fourth ventricle with membranes/walls.
The racemose variety of neurocysticercosis has an infrequent occurrence and is regarded as the most serious manifestation of neurocysticercosis as it can lead to sudden death by causing acute hydrocephalus. Hence, it is important to be familiar with its clinical manifestations and imaging appearances. Symptoms of the disease are usually secondary to inflammatory response, mass effect and hydrocephalus secondary to obstruction of the cerebrospinal fluid (CSF) pathway.2 With regard to radiological investigations, it is often difficult to diagnose this condition on CT as it may only show secondary signs such as mass effect, asymmetry
of ventricles or enlargement of cisterns without clear delineation of the cyst walls; hence, MRI forms a more specific investigation. In the present case, multiple cysticerci in the vesicular stage were seen in the cerebellopontine angle cisterns, the right perimedullary cistern, both foramen of Luschka and within the fourth ventricle causing significant mass effect and hydrocephalus.
Figure 3 Diffusion weighted images (A and B). No restriction of diffusion within the lesions in the right perimedullary cistern.
Figure 4 (A) Axial and (B) coronal postcontrast images. No enhancement of the wall of the lesions seen.
2
CASE PRESENTATION A 43-year-old man presented with a 3 month history of headache, vertigo and swaying while walking. There was no history
Karegowda LH, et al. BMJ Case Rep 2014. doi:10.1136/bcr-2014-203955
Unusual presentation of more common disease/injury
Figure 5 Histopathological section showing cysticercus larvae thrown in folds lined by pale eosinophilic membrane with numerous small cystic spaces. of vomiting or nausea. There was no history of seizures or altered behaviour. He was non-hypertensive, non-diabetic and had no significant past or family history. On clinical examination the patient was conscious and oriented. Neurological examination was positive for right cerebellar signs with intact higher mental functions and no cranial nerve deficits. Precontrast MRI revealed cystic lesions involving the right cerebellopontine angle cistern, the right perimedullary cistern, both foramen of Luschka and the fourth ventricle. The lesions were of CSF signal intensity on T1 and T2 sequences (figure 1)
and showed multiple thin hypointense septations which represent the walls/membranes of the cysticerci. These cyst walls/ membranes were best delineated on 3D FIESTA (threedimensional fast imaging with steady state acquisition) sequence (figure 2). Significant mass effect was noted in the form of compression of the right middle cerebellar peduncle and brainstem with obstruction to CSF outflow leading to hydrocephalus (figures 1 and 2). Diffusion-weighted imaging sequences showed no diffusion restriction (figure 3). Postcontrast sequence showed no significant enhancement of the walls of the cysticerci (figure 4). No obvious scolex was visualised and there was no abnormal meningeal enhancement. Serum and CSF ELISA tests for cysticercosis were positive. The patient underwent right retromastoid craniotomy with endoscopic third ventriculostomy under general anaesthesia for cyst excision. Gross specimen consisted of flattened glistening grey–white cystic lesions with smooth inner walls. Histopathology showed multiple cysticercus larvae thrown in folds lined by pale eosinophilic membrane with numerous small cystic spaces (figure 5). The patient received antihelminthic medication ( praziquental) after the surgery. He developed CSF leak from the wound site in the immediate postoperative period which was sutured with 2-0 ethilon and controlled successfully. The patient’s symptoms started to improve gradually and he was able to carry on his day-to-day activities normally by the end of 1 month. Follow-up CT of the brain (figure 6) showed significant decrease in the degree of hydrocephalus with complete removal of cysts.
Figure 6 Follow-up axial CT images after the surgery. (A) Right retromastoid craniotomy defect. (B–D) Complete removal of the cysts with normal-sized fourth ventricle.
Karegowda LH, et al. BMJ Case Rep 2014. doi:10.1136/bcr-2014-203955
3
Unusual presentation of more common disease/injury DISCUSSION Cysticercosis is a zoonosis caused by Taenia solium which most frequently involves the intracranial compartment (60–90% of the patients).3 The brain parenchyma is commonly affected by neurocysticercosis where it typically presents as a focal lesion with surrounding oedema at the grey–white matter interface which later calcifies. The ventricular system and the subarachnoid spaces may rarely be affected by the parasite and this form is known as racemose cysticercosis.4 The parasite usually shows various stages of evolution within the brain parenchyma, namely, live (vesicular), dying (colloidal vesicular and granular nodular) and dead (calcified nodular) stages. However, within the extra-axial space, the cysts are different from the parenchymal cysts as they exhibit abnormal large growth of the cystic membrane and remain in the vesicular stage with absent temporal degenerative changes. Also, majority of the extra-axial cysts show no scolex.2 4 5
MRI is the investigation of choice in diagnosing the condition due to its superior contrast resolution and direct multiplanar capability. In the present case, the lesions involved the CP angle cisterns, the right perimedullary cistern, both foramen of Luschka and the fourth ventricle. The walls of the cyst were well depicted on 3D FIESTA sequences as noted by other authors.6 Scolex, however, was not visualised in the present case even with FIESTA. The racemose variety can obstruct the ventricles or CSF outflow tracts either by direct mechanical obliteration or due to ependymitis leading to scarring. This could result in acute hydrocephalus and sudden death, mandating an early diagnosis and surgical intervention.7 In our case, the lesions were causing obstruction of the fourth ventricle and both foramen of Luschka resulting in acute hydrocephalus, which was treated promptly with surgical intervention leading to successful postoperative recovery of the patient. Acknowledgements Dr Manna Valiathan, Professor and Dr Swati Gupta, Postgraduate, Department of Pathology, KMC, Manipal. Competing interests None.
Learning points
Patient consent Obtained. Provenance and peer review Not commissioned; externally peer reviewed.
▸ Although uncommon, racemose cysticercosis is the most serious manifestation of cysticercosis as it can lead to sudden death due to acute hydrocephalus, and hence mandates an early diagnosis and surgical intervention. ▸ This form is different from the parenchymal cysts as they exhibit abnormal large growth of the cystic membrane and remain in the vesicular stage with absent temporal degenerative changes. ▸ MRI is the investigation of choice as CT often fails to delineate the cysts. ▸ 3D FIESTA (three-dimensional fast imaging with steady state acquisition) is an important advanced MRI sequence helpful in delineating the cyst walls/membranes.
REFERENCES 1 2 3 4 5 6 7
White AC Jr. Neurocysticercosis: updates on epidemiology, pathogenesis, diagnosis, and management. Annu Rev Med 2000;51:187–206. Kim SW, Kim MK, Oh SM, et al. Racemose cysticercosis in the cerebellar hemisphere. J Korean Neurosurg Soc 2010;48:59–61. Osborn AG. Diagnostic neuroradiology. 1st edn. Missouri: Mosby Year Book Inc, 1994:709–12. Mittal P, Mittal G. Intraventricular and subarachnoid racemose cysticercosis. Trop Parasitol 2011;1:111–12. Rahalkar MD, Shetty DD, Kelkar AB, et al. The many faces of cysticercosis. Clin Radiol 2000;55:668–74. Hingwala D, Chatterjee S, Kesavadas C, et al. Applications of 3D CISS sequence for problem solving in neuroimaging. Ind J Radiol 2011;21:90–7. Takayanagui OM, Odashima NS. Clinical aspects of neurocysticercosis. Parasitol Int 2006;55:S111–15.
Copyright 2014 BMJ Publishing Group. All rights reserved. For permission to reuse any of this content visit http://group.bmj.com/group/rights-licensing/permissions. BMJ Case Report Fellows may re-use this article for personal use and teaching without any further permission. Become a Fellow of BMJ Case Reports today and you can: ▸ Submit as many cases as you like ▸ Enjoy fast sympathetic peer review and rapid publication of accepted articles ▸ Access all the published articles ▸ Re-use any of the published material for personal use and teaching without further permission For information on Institutional Fellowships contact [email protected] Visit casereports.bmj.com for more articles like this and to become a Fellow
4
Karegowda LH, et al. BMJ Case Rep 2014. doi:10.1136/bcr-2014-203955
