Indian Journal of Nuclear Medicine
Home | About IJNM | Search | Current Issue | Past Issues | Instructions | Ahead of Print | Online submissionLogin 
Indian Journal of Nuclear Medicine
  Editorial Board | Subscribe | Advertise | Contact
Users Online: 97 Print this page  Email this page Small font size Default font size Increase font size


 
 Table of Contents     
INTERESTING IMAGE
Year : 2021  |  Volume : 36  |  Issue : 2  |  Page : 223-225  

Parathyroid carcinoma – A malignant cause of metabolic skeletal super scan on fluorodeoxyglucose positron emission tomography-Computed tomography


Division of PET/CT, Gemini Scans, Chennai, Tamil Nadu, India

Date of Submission14-Oct-2020
Date of Acceptance18-Nov-2020
Date of Web Publication21-Jun-2021

Correspondence Address:
Dr. Santhosh Sampath
Division of PET/CT, Gemini Scans, Vadapalani, Chennai - 600 026, Tamil Nadu
India
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ijnm.ijnm_213_20

Rights and Permissions
   Abstract 


Excessive abnormal tracer uptake in active tracer avid organ(s) with the suppression of physiological background tracer distribution is termed as super scan. Herein, we present an 18F-fluorodeoxyglucose positron emission tomography-computed tomography (FDG-PET/CT), where the metabolic pattern of skeletal super scan with coexistent parathyroid tumor was seen giving rise to the suspicion of primary hyperparathyroidism. It was subsequently diagnosed as a case of parathyroid carcinoma. Very high levels of serum parathormone in parathyroid carcinoma lead to accelerated bone turn over resulting in metabolic skeletal superscan in FDG-PET/CT which is seldom observed in parathyroid adenoma.

Keywords: 18F-fluorodeoxyglucose positron emission tomography-computed tomography, metabolic bone disease, parathyroid carcinoma, primary hyperparathyroidism, super scan


How to cite this article:
Sampath S, Jeeva G. Parathyroid carcinoma – A malignant cause of metabolic skeletal super scan on fluorodeoxyglucose positron emission tomography-Computed tomography. Indian J Nucl Med 2021;36:223-5

How to cite this URL:
Sampath S, Jeeva G. Parathyroid carcinoma – A malignant cause of metabolic skeletal super scan on fluorodeoxyglucose positron emission tomography-Computed tomography. Indian J Nucl Med [serial online] 2021 [cited 2021 Jul 27];36:223-5. Available from: https://www.ijnm.in/text.asp?2021/36/2/223/318881



A 35-year-old male presented with diffuse body ache and unexplained weight loss. 18F-fluorodeoxyglucose positron emission tomography-computed tomography (FDG-PET/CT) scan showed extensive FDG avid (maximum standardized uptake value [SUVmax] 8.0) mixed lytic-sclerotic lesions in the skull, mandible [arrows in [Figure 1]a and [Figure 1]b], maxilla, sternum, and all the ribs [arrows in [Figure 1]c and [Figure 1]d correspond to posterior left 10th rib]. Diffuse FDG uptake was visualized in all the vertebrae showing generalized sclerosis [arrow heads in [Figure 1]c and [Figure 1]d]. Multiple small and large osteolytic FDG avid (SUVmax 8.7) and non-FDG avid [arrows in [Figure 1]e and [Figure 1]f] lesions were visualized in bilateral pelvic bones. FDG avid cortical thinning, tunneling [arrowhead in [Figure 2]a], and endosteal scalloping were visualized in the appendicular skeleton [arrows in [Figure 2]a and [Figure 2]b]. Except for the physiological uptake in the brain, there was very low background FDG distribution. These findings together with mandibular involvement [arrow in [Figure 2]c] gave rise to METABOLIC SKELETAL SUPER SCAN (MSSS) pattern that would be otherwise seen in whole body skeletal scintigraphy of metabolic bone disease.
Figure 1: Axial computed tomography and fused positron emission tomography-computed tomography images of 18F-fluorodeoxyglucose positron emission tomography-computed tomography show extensive fluorodeoxyglucose avid (maximum standardized uptake value 8.0) mixed lytic-sclerotic lesions in mandible (arrows in a and b), and posterior left 10th rib (arrows in c and d). Diffuse fluorodeoxyglucose uptake is visualized in D10 vertebra showing generalized sclerosis (arrow heads in c and d). Multiple small and large osteolytic fluorodeoxyglucose avid (maximum standardized uptake value 8.7) and non fluorodeoxyglucose avid (arrows in e and f) lesions are visualized in bilateral pelvic bones

Click here to view
Figure 2: Coronal computed tomography (a), fused positron emission tomography-computed tomography (b) and maximum intensity projection (c) images show fluorodeoxyglucose avid cortical thinning, tunneling (arrowhead in a) and endosteal scalloping in the appendicular skeleton (arrows in a and b). Except for the physiological uptake in the brain, there is very low background fluorodeoxyglucose distribution (c)

Click here to view


A mixed solid-cystic lesion measuring 36 mm × 32 mm was seen in the posteroinferior aspect of the left lobe of thyroid [arrows in [Figure 3]a and [Figure 3]b] with very faint FDG uptake (SUVmax 2.2) in the enhancing solid components [arrows in [Figure 3]c and [Figure 3]d]. With the background of metabolic bone disease, this lesion was suggested to be a parathyroid tumor. The FDG avid lytic lesions were considered as brown tumors. Further evaluation revealed very high serum calcium (16 mg/ml) and parathormone (2831 pg/ml). The patient was subsequently treated with left inferior parathyroidectomy. The parathyroid specimen weighed 25 gram (measuring of 4.5 cm × 3.5 cm × 1.5 cm) and was diagnosed with parathyroid carcinoma due to lymphovascular invasion, stage pT1. With the absence of nonosseous lesions in the PET/CT, the stage was concluded as T1N0M0.
Figure 3: Coronal computed tomography (a) and fused positron emission tomography-computed tomography (b) show a mixed solid-cystic lesion in the posteroinferior aspect of the left lobe of thyroid (arrows in a and b). Axial computed tomography (c) and fused positron emission tomography-computed tomography (d) show very faint fluorodeoxyglucose uptake in the enhancing solid components (arrows in c and d)

Click here to view


Parathyroid carcinoma is a rare malignancy generally diagnosed after the surgery for primary hyperparathyroidism (PHPT). Those patients have significantly higher serum parathyroid hormone and calcium levels compared with other causes of PHPT.[1] Only two cases of parathyroid carcinoma presenting as MSSS in PET/CT have been reported in the literature.[2],[3] In both cases, PET/CT was done for the evaluation of recurrent parathyroid carcinoma. In our case, a provisional diagnosis of PHPT was considered based on the PET/CT findings. Marrow infiltrative disorders such as leukemia[4] and skeletal metastases from poorly differentiated solid malignancies have also been reported to cause SSS in FDG-PET/CT.[5],[6] In metastatic superscan of PET/CT, the distal appendicular skeleton is usually spared in adults due to the absence of red bone marrow, which is a prerequisite for primary hematological spread of tumor cells to the bone extracellular matrix.

In metabolic bone disease, the increased FDG uptake represents elevated metabolism associated with increased bone turn over (osteoclastic and osteoblastic activity) and hence the entire axial and appendicular skeleton show hypermetabolism. Parathyroid carcinoma is known to be poorly FDG avid.[7],[8],[9] A MSSS pattern coupled with parathyroid lesion should raise the suspicion of parathyroid carcinoma and appropriate curative treatment should be provided. Almost complete resolution of FDG uptake with improvement in cortical mineralization is observed after parathyroidectomy.[2]

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient (s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
   References Top

1.
Schaapveld M, Jorna FH, Aben KK, Haak HR, Plukker JT, Links TP. Incidence and prognosis of parathyroid gland carcinoma: A population-based study in The Netherlands estimating the preoperative diagnosis. Am J Surg 2011;202:590-7.  Back to cited text no. 1
    
2.
do Vale RH, Queiroz MA, Coutinho AM, Buchpiguel CA, de Menezes MR. 18F-FDG PET/CT Osteometabolic activity in metastatic parathyroid carcinoma. Clin Nucl Med 2016;41:724-5.  Back to cited text no. 2
    
3.
Güney İB, Paydaş S, Ballı HT. Super scan caused by parathyroid carcinoma observed both in 18F-FDG PET/CT scan and Tc-99m MDP bone scintigraphy. Mol Imaging Radionucl Ther 2017;26:116-9.  Back to cited text no. 3
    
4.
Parida GK, Soundararajan R, Passah A, Bal C, Kumar R. Metabolic skeletal superscan on 18F-FDG PET/CT in a case of acute lymphoblastic leukemia. Clin Nucl Med 2015;40:567-8.  Back to cited text no. 4
    
5.
Su HY, Liu RS, Liao SQ, Wang SJ. F-18 FDG PET superscan. Clin Nucl Med 2006;31:28-9.  Back to cited text no. 5
    
6.
Bailly M, Besse H, Kerdraon R, Metrard G, Gauvain S. 18F-FDG PET/CT superscan in prostate cancer. Clin Nucl Med 2014;39:912-4.  Back to cited text no. 6
    
7.
Andersen KF, Beste AE. Brown tumors due to primary hyperparathyroidism in a patient with parathyroid carcinoma mimicking skeletal metastases on (18)F-FDG PET/CT. Diagnostics (Basel) 2015;5:290-3.  Back to cited text no. 7
    
8.
Shim H, Kim BS. 18F-FDG PET findings of a parathyroid cancer with cortical skeletal demineralization. Clin Nucl Med 2012;37:293-5.  Back to cited text no. 8
    
9.
Li M, Lu H, Gao Y. FDG-anorectic parathyroid carcinoma with FDG-avid bone metastasis on PET/CT images. Clin Nucl Med 2013;38:916-8.  Back to cited text no. 9
    


    Figures

  [Figure 1], [Figure 2], [Figure 3]



 

Top
  
 
  Search
 
  
    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
    Access Statistics
    Email Alert *
    Add to My List *
* Registration required (free)  

 
  In this article
    Abstract
    References
    Article Figures

 Article Access Statistics
    Viewed128    
    Printed0    
    Emailed0    
    PDF Downloaded25    
    Comments [Add]    

Recommend this journal