Table of Contents  
CASE REPORT
Year : 2013  |  Volume : 6  |  Issue : 4  |  Page : 462-464  

Cerebral metastasis masquerading as cerebritis: A case of misguiding history and radiological surprise!


Department of Neurosurgery, Nizam's Institute of Medical Sciences, Hyderabad, India

Date of Web Publication17-Sep-2013

Correspondence Address:
Ashish Kumar
Department of Neurosurgery, Nizam's Institute of Medical Sciences, Punjagutta, Hyderabad - 500 082, Andhra Pradesh
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0975-2870.118291

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  Abstract 

Cerebral metastases usually have a characteristic radiological appearance. They can be differentiated rather easily from any infective etiology. Similarly, positive medical history also guides the neurosurgeon towards the possible diagnosis and adds to the diagnostic armamentarium. However, occasionally, similarities on imaging may be encountered where even history could lead us in the wrong direction and tends to bias the clinician. We report a case of a 40-year-old female with a history of mastoidectomy for otitis media presenting to us with a space occupying lesion in the right parietal region, which was thought pre-operatively as an abscess along with the cerebritis. Surprisingly, the histopathology proved it to be a metastatic adenocarcinoma. Hence, a ring enhancing lesion may be a high grade neoplasm/metastasis/abscess, significant gyral enhancement; a feature of cerebritis is not linked with a neoplastic etiology more often. This may lead to delayed diagnosis, incorrect prognostication and treatment in patients having coincidental suggestive history of infection. We review the literature and highlight the key points helping to differentiate an infective from a neoplastic pathology which may look similar at times.

Keywords: Cerebritis, gyral enhancement, infection, metastasis


How to cite this article:
Kumar A, Vinay B, Aneel K, Barada SP. Cerebral metastasis masquerading as cerebritis: A case of misguiding history and radiological surprise!. Med J DY Patil Univ 2013;6:462-4

How to cite this URL:
Kumar A, Vinay B, Aneel K, Barada SP. Cerebral metastasis masquerading as cerebritis: A case of misguiding history and radiological surprise!. Med J DY Patil Univ [serial online] 2013 [cited 2019 Oct 18];6:462-4. Available from: http://www.mjdrdypu.org/text.asp?2013/6/4/462/118291


  Introduction Top


Usually pattern of post contrast enhancement in neurosurgical practice provides a clue towards a possible etiology. This guides and modifies our management strategy from time to time. However, sometimes radiological surprises do crop up and create diagnostic dilemmas in patients with a typical history contrary to the reality. We encountered a similar patient where, an abscess along with cerebritis was postulated in a patient of chronic suppurative otitis media (CSOM). The histopathology proved it to be a case of a metastatic adenocarcinoma confirmed after immuno-histochemistry.


  Case Report Top


A 40-year-old female presented to us with a history of right sided dull aching, diffuse headaches for the last

1 month. She had undergone right sided mastoidectomy for CSOM 5 years back. Presently there was no history of any ear discharge or active signs of infection. Neurological examination was normal except for bilateral papilledema. Computed tomography (CT) scan revealed a ring enhancing lesion in the right parietal region with extensive peri-lesional edema [Figure 1]. Magnetic resonance imaging (MRI) contrast confirmed the ring enhancing lesion in the right parietal lobe along with gyral enhancement in the surrounding region [Figure 2]. This imageology was more in favor of an infectious etiology given the history of CSOM. However, mastoids didn't reveal any fluid collection suggestive of mastoiditis [Figure 3]. Ear, nose and throat (ENT) consultation also did not reveal any positive inputs. The patient was undertaken for a burr hole aspiration and pus retrieval in order to send it for culture and sensitivity. To our surprise, hemorrhagic fluid was aspirated and hence the burr hole was converted to craniotomy and biopsy of the wall proved it to be metastatic adenocarcinoma [Figure 4]. This was re-confirmed on immunohistocytochemistry (Cytokeratin 7 and Thyroid Transcription Factor I positive). Patient made an uneventful recovery and underwent thorough examination for a primary which was from lungs diagnosed by CT Chest as the X-ray looked nearly normal. She was referred for radiation and chemotherapy thereafter.
Figure 1: Contrast CT showing ring enhancing lesion in parietal region with extensive peri-lesional edema.

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Figure 2: Axial, sagittal and coronal contrast MRI revealing ring enhancing lesion along with surrounding leptomeningeal and gyral enhancement with mass effect. This imageology may look similar for cerebritis and carcinomatosis meningitis.

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Figure 3: (A) The squash smears showing epithelial cells arranged as acinus. Toludine blueX100 (B) the histopath sections showing glandular and papillary arrangement of epithelial cells infiltrating brain with atypia H&EX 100 (C) Cytokeratin 7 showing strong cytoplasmic positivity in tumor cells (HRP Polymer CK7×100) (D) Strong nuclear staining for TTF-1 (HRP Polymer TTF-1 X100).

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Figure 4: The contrast MRI showing no active mastoiditis.

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  Discussion Top


Smirniotopoulos et al. have described various patterns of contrast enhancement of the brain and meninges. [1] Leptomeningeal enhancement is usually seen in meningitis and meningoencephalitis. The primary mechanism of this enhancement is the breakdown of the blood brain barrier without angiogenesis. Glycoproteins are released after the bacterial breakdown which increases the vascular permeability. However, neoplastic processes like ependymomas, glioblastomas and medulloplastomas also may result in carcinomatous meningitis. This enhancement is thicker, nodular and clumpier in comparison to an inflammatory pathology which will result in fine, linear streak like enhancement. Authors also pointed out that superficial gyral "serpentine" enhancement will usually be caused by an inflammatory or an infective pathology and are very rarely neoplastic in origin. Other mimics may be meningo-encephalitis, reperfusion injury after an infarct, vasodilatation phase of migraine, posterior reversible encephalopathy syndrome and vasodilation after a seizure. Usually history provides a clue and in our case it literally guided us in a wrong direction, making us believe in favor of an infective etiology first. Chiang et al. have tried to differentiate between a pyogenic brain abscess and a high grade necrotic neoplasm by way of 3 Tesla magnetic resonance spectroscopy (MRS) and perfusion-diffusion imaging. [2] The MRS shows the presence of amino-acids (valine, leucine, iso-leucine, acetate, alanine) and a low apparent diffusion coefficient values in the central cavities of brain abscesses when compared to high grade neoplasms. Furthermore, the relative cerebral blood-flow is high at the outer walls of a tumor in comparison to an abscess. Here, they were able to differentiate on the basis of these modalities when conventional MRI imaging proved to be almost similar. Many authors have stressed on the role of diffusion weighted imaging (DWI) in differentiating between cystic metastasis and abscess. [3],[4],[5] On the contrary, Hartmann et al. have also pointed out that restricted diffusion may be characteristic of many ring enhancing lesions, but it is definitely not pathognomonic of brain abscess. [6] Furthermore, the imageological diagnosis of various sub-types of brain abscesses viz., tuberculosis, fungal and pyogenic with the help of conventional, DWI and MRS can be made with surety. [7] Even if DWI would have shown a loss of restriction in our case, early gyral enhancement could never have shown restricted diffusion of water molecules, which characteristically occurs in the center of an abscess due to the presence of thick and purulent material. Hence, in this stage abscess formation i.e. cerebritis, the worth of a DWI still needs to be debated.

As mentioned earlier, leptomeningeal spread on the other hand may also be confused with features of meningitis. Collie et al. reviewed imaging features of 41 patients with leptomeningeal metastasis and they found that 67% of patients had pial enhancement and nodularity as the most common finding. [8] Gadolinium based MRI was performed in all the patients, which were diagnosed based on imaging as well as cytology. Neural enhancement and white matter changes were the other imageological findings. Authors concluded that a CT can be misleading in almost 66% patients and cytology may also be negative and hence MRI becomes most reliable in such patients. Moreover, Singh et al. studied three sequences of MRI to pick up leptomeningeal spread and contrast enhanced T1-weighted images were found to be the more sensitive than unenhanced/enhanced fluid attenuated inversion recovery images. [9] The most common sites of primary are breast and lung carcinomas and the most common sites of the leptomeningeal spread are quadrigeminal cisterns, perimesencephalic cisterns, superior cerebellar cisterns, ventricular ependyma, high parietal subarachnoid space and none were involved in our patient. [10]

To summarize, this case report highlights the ambiguity of radiological and historical findings in patients with brain metastasis, which may mislead the surgeons and hence trigger incorrect management algorithms for patients. In our case, the plan changed from a simple burr hole to a craniotomy and the prognosis changed from better to worse! Therefore, even in the presence of gyral enhancement and absence of typical "leptomeningeal carcinomatosis" features on gadolinium MRI in patients with a suggestive history of infective etiology, one should try to remain unbiased and a battery of investigations including, primary work up for metastasis, Cerebro-spinal fluid cytology, and DWI should be kept in mind prior to any surgical adventure. This will help us in prognosticating the disease well and in subsequent initiation of adjuvant therapies thereafter.

 
  References Top

1.Smirniotopoulos JG, Murphy FM, Rushing EJ, Rees JH, Schroeder JW. Patterns of contrast enhancement in the brain and meninges. Radiographics 2007;27:525-51.  Back to cited text no. 1
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2.Chiang IC, Hsieh TJ, Chiu ML, Liu GC, Kuo YT, Lin WC. Distinction between pyogenic brain abscess and necrotic brain tumour using 3-tesla MR spectroscopy, diffusion and perfusion imaging. Br J Radiol 2009;82:813-20.  Back to cited text no. 2
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3.Shetty P, Moiyadi A, Pantvaidya G, Arya S. Cystic metastasis versus brain abscess: Role of MR imaging in accurate diagnosis and implications on treatment. J Cancer Res Ther 2010;6:356-8.  Back to cited text no. 3
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4.Ebisu T, Tanaka C, Umeda M, Kitamura M, Naruse S, Higuchi T, et al. Discrimination of brain abscess from necrotic or cystic tumors by diffusion-weighted echo planar imaging. Magn Reson Imaging 1996;14:1113-6.   Back to cited text no. 4
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5.Kim YJ, Chang KH, Song IC, Kim HD, Seong SO, Kim YH, et al. Brain abscess and necrotic or cystic brain tumor: Discrimination with signal intensity on diffusion-weighted MR imaging. AJR Am J Roentgenol 1998;171:1487-90.  Back to cited text no. 5
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6.Hartmann M, Jansen O, Heiland S, Sommer C, Münkel K, Sartor K. Restricted diffusion within ring enhancement is not pathognomonic for brain abscess. AJNR Am J Neuroradiol 2001;22:1738-42.   Back to cited text no. 6
    
7.Luthra G, Parihar A, Nath K, Jaiswal S, Prasad KN, Husain N, et al. Comparative evaluation of fungal, tubercular, and pyogenic brain abscesses with conventional and diffusion MR imaging and proton MR spectroscopy. AJNR Am J Neuroradiol 2007;28:1332-8.   Back to cited text no. 7
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8.Collie DA, Brush JP, Lammie GA, Grant R, Kunkler I, Leonard R, et al. Imaging features of leptomeningeal metastases. Clin Radiol 1999;54:765-71.  Back to cited text no. 8
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9.Singh SK, Leeds NE, Ginsberg LE. MR imaging of leptomeningeal metastases: Comparison of three sequences. AJNR Am J Neuroradiol 2002;23:817-21.  Back to cited text no. 9
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10.Yousem DM, Patrone PM, Grossman RI. Leptomeningeal metastases: MR evaluation. J Comput Assist Tomogr 1990;14:255-61.  Back to cited text no. 10
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    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4]



 

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