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Year : 2022  |  Volume : 37  |  Issue : 1  |  Page : 97-98  

Skeletal metastases of unknown primary: a rare presentation of carcinoma pancreas on fludeoxyglucose positron emission tomography–Computed tomography

Department of Nuclear Medicine, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India

Date of Submission08-Jul-2021
Date of Decision07-Aug-2021
Date of Acceptance31-Aug-2021
Date of Web Publication25-Mar-2022

Correspondence Address:
Dr. Manish Ora
Department of Nuclear Medicine, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow - 226 014, Uttar Pradesh
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijnm.ijnm_105_21

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Skeletal metastases of unknown primary represent skeletal metastases where primary tumors remain obscure. They usually arise from lung and prostate cancer. We present a case of a young male who presented with severe bone pains, weight loss, and generalized weakness. Fludeoxyglucose positron emission tomography–computed tomography reveals extensive skeletal metastases, a mass in the pancreas tail, and other metastatic lesions. He had no liver or lung metastases. This case presents a rare presentation of carcinoma pancreas.

Keywords: Carcinoma unknown primary, pancreatic carcinoma, positron emission tomography/computed tomography, skeletal metastases of unknown primary, skeletal metastasis

How to cite this article:
Saini VK, Markam K, Nazar AH, Ora M, Gambhir S. Skeletal metastases of unknown primary: a rare presentation of carcinoma pancreas on fludeoxyglucose positron emission tomography–Computed tomography. Indian J Nucl Med 2022;37:97-8

How to cite this URL:
Saini VK, Markam K, Nazar AH, Ora M, Gambhir S. Skeletal metastases of unknown primary: a rare presentation of carcinoma pancreas on fludeoxyglucose positron emission tomography–Computed tomography. Indian J Nucl Med [serial online] 2022 [cited 2022 Aug 18];37:97-8. Available from:

A 23-year-old patient presented with diffuse bony pains, weight loss, and generalized weakness for 2 months. Blood investigations suggested hypercalcemia (serum calcium 12.4 mg/ dl) and moderate renal failure (serum creatinine 1.88 mg/dl). Contrast-enhanced computed tomography chest was suggestive of multiple bony lesions in the ribs and vertebras. A provisional diagnosis of skeletal metastases of unknown primary (SMUP) was made. Fludeoxyglucose (FDG) positron emission tomography–computed tomography (PET/CT) revealed a mass in the tail of the pancreas with regional, nonregional lymph nodes (LNs), extensive skeletal metastases. However, no metastases were noted in the liver or lung [Figure 1]. Bone marrow examination was suggestive of metastatic infiltration from adenocarcinoma. He was started on palliative chemotherapy with antihypercalcemic drugs and narcotic analgesics. He succumbed after 3 months of diagnosis.
Figure 1: (a) Maximum intensity projection image shows extensive abnormal tracer uptake in the axial and visualized appendicular skeletal system (red arrows), abnormal tracer in the uptake in the left upper abdomen (blue arrow), and central abdominal region (green arrow). (b) Coronal fused image showing pancreatic lesion (blue arrow), multiple discrete and conglomerated retroperitoneal lymph nodes (green arrow), and skeletal lesions (red arrow). (c and d) Axial images show cervical and mediastinal lymph nodes (green arrow). (e and f) Fused axial image showing mass lesion in the tail of the pancreas (blue arrow) and abdominal-retroperitoneal lymph nodes (green arrow). (g) Fused axial image showing abdominal-retroperitoneal lymph nodes (green arrow). (c-h) Extensive lytic sclerotic skeletal lesions are noted in the visualized bones (red arrow)

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SMUP represents enigmatic entities without a primary site identified. Cancer of unknown primary accounts for 2% of all cancers. It is characterized by an aggressive clinical outcome and inadequate response to chemotherapy.[1] Lung cancer is the most frequently identified primary tumor (25%– 67%), followed by prostate cancer, lymphoma, and kidney, gastrointestinal, and breast cancer.[2] Although almost all tumors can metastasize to the skeleton during their natural history, epithelial cancers are characterized by a particular propensity for this type of dissemination. SMUP from pancreatic cancer (PC) is seldomly reported.[3],[4] PC usually metastasizes to regional LNs, liver, adjacent organs, and lungs.[5] Skeletal metastases are an uncommon but clinically imperative occurrence in PC. The most common sites of skeletal metastases are vertebrae, hips, and ribs. Both blastic and lytic lesions are noted, with a predominance of blastic lesions.[6]

FDG PET/CT is considered a good modality for metastatic workup. It has sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 90%, 76%, 90%, 76%, and 86%, respectively. The pooled sensitivity and specificity to differentiate between PC and chronic pancreatitis are 90% and 84%, respectively.[7] PC is usually present at an advanced stage. Only about 15% of the patients present with a resectable disease can undergo “curative” surgery. Even then, local and systemic recurrence is not uncommon. Patients with metastatic and locally advanced PC receive palliative treatment.[8] Median survival for locally advanced PC is just 6–10 months. However, in metastatic disease, this falls to 3–6 months. Overall, the 5-year survival is <4%.[9] This case report highlights the utility of FDG PET/CT in the patients of SMUP. FDG PET/CT was able to confirm the site of primary cancer. This case represents an extensive SMUP from PC in a young male with no metastases to the liver or lung.

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.

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Conflicts of interest

There are no conflicts of interest.

   References Top

Massard C, Loriot Y, Fizazi K. Carcinomas of an unknown primary origin – Diagnosis and treatment. Nat Rev Clin Oncol 2011;8:701-10.  Back to cited text no. 1
Argentiero A, Solimando AG, Brunetti O, Calabrese A, Pantano F, Iuliani M, et al. Skeletal metastases of unknown primary: Biological landscape and clinical overview. Cancers (Basel) 2019;11:E1270.  Back to cited text no. 2
Pneumaticos SG, Savidou C, Korres DS, Chatziioannou SN. Pancreatic cancer's initial presentation: Back pain due to osteoblastic bone metastasis. Eur J Cancer Care (Engl) 2010;19:137-40.  Back to cited text no. 3
Argentiero A, Calabrese A, Solimando AG, Notaristefano A, Panarelli MM, Brunetti O. Bone metastasis as primary presentation of pancreatic ductal adenocarcinoma: A case report and literature review. Clin Case Rep 2019;7:1972-6.  Back to cited text no. 4
Voutsadakis IA, Doumas S, Tsapakidis K, Papagianni M, Papandreou CN. Bone and brain metastases from ampullary adenocarcinoma. World J Gastroenterol 2009;15:2665-8.  Back to cited text no. 5
Borad MJ, Saadati H, Lakshmipathy A, Campbell E, Hopper P, Jameson G, et al. Skeletal metastases in pancreatic cancer: A retrospective study and review of the literature. Yale J Biol Med 2009;82:1-6.  Back to cited text no. 6
Rijkers AP, Valkema R, Duivenvoorden HJ, van Eijck CH. Usefulness of F-18-fluorodeoxyglucose positron emission tomography to confirm suspected pancreatic cancer: A meta-analysis. Eur J Surg Oncol 2014;40:794-804.  Back to cited text no. 7
Ansari D, Gustafsson A, Andersson R. Update on the management of pancreatic cancer: Surgery is not enough. World J Gastroenterol 2015;21:3157-65.  Back to cited text no. 8
Allendorf JD, Lauerman M, Bill A, DiGiorgi M, Goetz N, Vakiani E, et al. Neoadjuvant chemotherapy and radiation for patients with locally unresectable pancreatic adenocarcinoma: Feasibility, efficacy, and survival. J Gastrointest Surg 2008;12:91-100.  Back to cited text no. 9


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