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 Table of Contents     
CASE REPORT
Year : 2016  |  Volume : 31  |  Issue : 4  |  Page : 295-297  

Intracranial meningioma, mimicking brain metastasis on 18F sodium fluoride bone scan in a case of carcinoma cervix


1 Department of Nuclear Medicine, Sri Venkateswara Institute of Medical Sciences, Tirupati, Andhra Pradesh, India
2 Department of Radiology, Sri Venkateswara Institute of Medical Sciences, Tirupati, Andhra Pradesh, India

Date of Web Publication19-Sep-2016

Correspondence Address:
Tekchand Kalawat
Department of Nuclear Medicine and Positron Emission Tomography-Computerized Tomography, Sri Venkateswara Institute of Medical Sciences, Tirupati - 517 507, Andhra Pradesh
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0972-3919.190800

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   Abstract 


Bone scintigraphy (BS) is a well--established commonly used imaging modality for staging and follow--up evaluation of cancer patients. Occasionally, BS may show asymptomatic unusual extraosseous lesions in the body which may or may not be related to primary disease. We here present an interesting case of carcinoma cervix in whom 18F sodium fluoride positron emission tomography-computerized tomography (PET-CT) bone scan detected an intracranial lesion. Initially, this lesion was suspected as brain metastasis; however, later on, combined PET--CT images and contrast-enhanced CT confirmed this lesion as calcified falcine meningioma in the right posterior parietal region.

Keywords: Carcinoma cervix, 18F sodium fluoride bone scan, meningioma, soft-tissue calcification


How to cite this article:
Priya RR, Manthri RG, Lakshmi AY, Kalawat T. Intracranial meningioma, mimicking brain metastasis on 18F sodium fluoride bone scan in a case of carcinoma cervix. Indian J Nucl Med 2016;31:295-7

How to cite this URL:
Priya RR, Manthri RG, Lakshmi AY, Kalawat T. Intracranial meningioma, mimicking brain metastasis on 18F sodium fluoride bone scan in a case of carcinoma cervix. Indian J Nucl Med [serial online] 2016 [cited 2019 May 21];31:295-7. Available from: http://www.ijnm.in/text.asp?2016/31/4/295/190800




   Introduction Top


Radionuclide bone scintigraphy (BS) is a versatile imaging technique for evaluation of both local and systemic bone diseases. It is a survey of skeleton, when performed, detects abnormal osteoblastic activity in affected bones much before patient presents with clinical symptoms. BS is widely accepted as an important imaging modality for staging and follow-up of cancer patients.[1],[2] Occasionally, BS shows nonosseous, soft-tissue lesions in the body due to focal bone-seeking radiotracer accumulation. In the present case of carcinoma cervix,18F sodium fluoride (NaF) bone scan localized a focal area of radiotracer uptake in the right posterior parietal region, mimicking brain metastasis.


   Case Report Top


A 65-year-old postmenopausal woman, known case of squamous cell carcinoma cervix, underwent total abdominal hysterectomy and bilateral salpingo-oophorectomy with pelvic lymph node dissection. Histopathological findings revealed nonkeratinizing type squamous cell carcinoma of the cervix with no lymph node invasion. She was treated with local radiotherapy (RT). After 6 months, the patient presented with complaints of low backache, radiating to both lower limbs associated with paresthesia. Considering the clinical symptoms of backache, she was advised to undergo bone scan.18F NaF PET CT bone scan image [Figure 1]a and sagittal images [Figure 1]b,[Figure 1]c,[Figure 1]d shows post radio therapy osteoporotic changes in lower part of the lumbar spine and sacral region with L-5 vertebral body insufficiency fracture. Images also showed an area of increased radiotracer uptake in the right side of brain posterior parietal region. Initially, the lesion was suspected as brain metastasis; however, on further evaluation in PET-CT images, it was diagnosed as calcified nonaxial meningioma. Subsequently, she was examined with contrast-enhanced CT (CECT) [Figure 2]. The findings in CECT confirmed the lesion as a mildly enhancing extra-axial, well-defined hyperdense lesion with calcification, located in the right parasagittal falx region, causing displacement of the adjacent cortex due to mass effect. Hypodensity was noted in the right parietofrontal region, compressing the right lateral ventricle with mild midline shift to the left side. The final impression of CECT was suggestive of right falcine meningioma, causing mass effect and midline shift with edema in the right parietal region.
Figure 1:18F sodium fluoride bone scan image (a), PET, CT and PET CT sagittal images (b-d) shows post radiotherapy changes (yellow arrow shows L-5 vertebral body insufficiency fracture). Red arrow mark shows non osseous intracranial area of increased 18F sodium fluoride uptake in the right posterior parietal region

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Figure 2: Brain CE CT, transaxial image shows a calcified falcine meningioma in the right posterior parietal region with mass effect and edema in adjacent tissue corresponding to the 18F sodium fluoride bone scan, non osseous, intra cranial radiotracer uptake site

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   Discussion Top


In early 1970, easy availability of technetium labeled radiopharmaceuticals for bone imaging surpassed the popularity of 18F NaF bone scan.[3],[4] Since then,99mTc methylene diphosphonate (MDP) BS has been playing important role in diagnosis and management of various benign and malignant bone diseases.[5],[6] It is widely available, simple, and easy to perform test which detects bone lesions 6–12 months earlier than structural imaging modalities. With the availability of PET-CT scanners and medical cyclotrons,18F NaF PET-CT bone scan has regained attention and many centers are now routinely performing this test for metastatic workup in cancer patients.18F NaF PET-CT has clinical advantage over conventional 99mTc MDP BS as it provides comprehensive functional and structural details in single test.[7]

Occasionally,99mTc MDP BS and 18F NaF scans show sites of abnormal radiotracer uptake in soft tissue. These lesions can be benign or malignant. The possible factors for increased soft-tissue uptake of bone-seeking radiotracer result from increased extracellular fluid expansion, vascularity, and high regional availability of calcium and phosphate salt leaked in the extracellular space from hypoxic or dead cells.[8]

Bone-seeking radiopharmaceuticals can accumulate in intracranial lesions due to both benign and malignant etiologies which include brain stroke, tumors, and metastatic lesions.[9] In this case of carcinoma cervix,18F NaF scan detected focal uptake in an intracranial lesion. Carcinoma cervix is a gynecological malignancy that rarely causes brain metastasis. There are few case reports documenting brain metastasis in patients with aggressive type of carcinoma cervix.[10] In the present case, initially, this lesion was suspected as brain metastasis; however, later on, when the images were examined in detail with both PET-CT and separately with CECT, it was diagnosed as falcine meningioma.

Meningioma is a common intracranial benign tumor, with twice incidence in females. The reported risk factors for meningioma include trauma, hormone replacement therapy, and breast cancer.[11] In many patients, they are silent and are diagnosed as incidental finding on CT or magnetic resonance imaging. About 25% of the meningiomas show calcification and can be visualized on radionuclide bone scan as an incidental finding as seen in the present case.[12]


   Conclusion Top


18F NaF PET-CT scan is a highly sensitive and specific test for detection of osseous lesions in the body. There is no association of meningioma with carcinoma cervix, and it is a rare coincidental finding as seen in the present case. Reading bone scan in such cases indicates that all pathological observations may not always be associated with primary disease but may be synchronous soft-tissue abnormalities of benign or malignant etiologies mimicking a metastatic lesion.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
   References Top

1.
Baker RR, Holmes ER 3rd, Alderson PO, Khouri NF, Wagner HN Jr. An evaluation of bone scans as screening procedures for occult metastases in primary breast cancer. Ann Surg 1977;186:363-8.  Back to cited text no. 1
    
2.
Gupta V. Bone scintigraphy in the evaluation of cancer. Kathmandu Univ Med J (KUMJ) 2005;3:243-8.  Back to cited text no. 2
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Blau M, Nagler W, Bender MA. Fluorine-18: A new isotope for bone scanning. J Nucl Med 1962;3:332-4.  Back to cited text no. 3
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4.
Subramanian G, McAfee JG. A new complex of 99mTc for skeletal imaging. Radiology 1971;99:192-6.  Back to cited text no. 4
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Kalawat TC, Narayan R, Ravi P, Lakshmi AY. Utility of bone scintigraphy in diagnosis of post-traumatic osteitis pubis. Indian J Nucl Med 2013;28:105-7.  Back to cited text no. 5
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6.
Brown ML, Collier BD Jr., Fogelman I. Bone scintigraphy: Part 1. Oncology and infection. J Nucl Med 1993;34:2236-40.  Back to cited text no. 6
    
7.
Bastawrous S, Bhargava P, Behnia F, Djang DS, Haseley DR. Newer PET application with an old tracer: Role of 18F-NaF skeletal PET/CT in oncologic practice. Radiographics 2014;34:1295-316.  Back to cited text no. 7
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8.
Gentili A, Miron SD, Bellon EM. Nonosseous accumulation of bone-seeking radiopharmaceuticals. Radiographics 1990;10:871-81.  Back to cited text no. 8
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9.
Kannivelu A, Padhy AK, Srinivasan S, Ali SZ. Extraosseous uptake of technetium-99m methylene diphosphonate by an acute territorial cerebral infarct in a classical biodistribution pattern. Indian J Nucl Med 2013;28:240-2.  Back to cited text no. 9
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10.
Amita M, Sudeep G, Rekha W, Yogesh K, Hemant T. Brain metastasis from cervical carcinoma – A case report. MedGenMed 2005;7:26.  Back to cited text no. 10
    
11.
Wiemels J, Wrensch M, Claus EB. Epidemiology and etiology of meningioma. J Neurooncol 2010;99:307-14.  Back to cited text no. 11
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12.
Derlin T, Mester J, Klutmann S. Abnormal F-18 fluoride uptake in intracranial meningiomas on PET/CT. Clin Nucl Med 2010;35:806-7.  Back to cited text no. 12
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    Figures

  [Figure 1], [Figure 2]



 

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