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Calcified peritoneal metastasis identified on 18F-fluoride positron emission tomography/computed tomography: Importance of extraosseous uptake of F-18 fluoride
Address for correspondence: Dr. Venkatesh Rangarajan, Department of Nuclear Medicine and Molecular Imaging, Tata Memorial Hospital, Parel, Mumbai - 400 012, Maharashtra, India. E-mail: drvrangarajan@gmail.com
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Abstract
F-18 NaF positron emission tomography/computed tomography (PET/CT) is used for the evaluation of malignant and nonmalignant osseous disease. Extraosseous uptake of 18 fluoride-NaF has been observed in the arterial vasculature, gastrointestinal tract, and genitourinary tract. We describe a case of a woman with carcinoma of unknown primary in whom F-18 NaF PET/CT showed tracer uptake in the calcified peritoneal metastasis. Extraosseous findings on F-18 NaF PET/CT, though rare, may be visualized and may result in important management changes.
Keywords
18F-fluoride positron emission tomography/computed tomography
bone scintigraphy
calcified soft tissue metastasis
extraosseous finding
F-18 NaF positron emission tomography/computed tomography (PET/CT) is used routinely for bone imaging for the detection of malignant and nonmalignant osseous disease.[12] Extraosseous uptake of 18F-NaF (18 fluoride NaF) has been observed in structures such as the arterial vasculature, gastrointestinal tract, and genitourinary tract.[3456] As a bone-seeking radiopharmaceutical, 18F-NaF can localize in extraosseous calcifying lesions. Lesions containing dystrophic or microscopic calcification or calcified visceral metastases can show focal uptake of 18F-NaF.[78910] Tc-99m methylene diphosphonate uptake has been reported in ovarian carcinoma and its soft tissue metastases.[11] In literature, there is one case report of F-18 fluoride uptake in calcified extraosseous metastases from ovarian papillary serous adenocarcinoma.[12] We describe a case of a 73-year-old woman with carcinoma of unknown primary in whom F-18 NAF PET/CT showed tracer uptake in the calcified peritoneal metastasis. She presented with abdominal distension, and ascitic fluid cytology was positive for malignant cells, suggestive of metastatic adenocarcinoma. She underwent F-18F bone scan for evaluation of skeletal metastases. Whole body F-18F PET/CT maximum intensity projection (MIP) [Figure 1] showed focal increased tracer uptake in the right iliac fossa. Axial PET/CT fused [Figure 2] showed increased tracer uptake corresponding to calcified soft tissue peritoneal metastasis. No evidence of skeletal metastases was seen. Figure 3 shows the coronal and sagittal images of the same patient. Contrast-enhanced CT scan [Figure 4] was done, which demonstrated the presence of calcified peritoneal metastasis. However, the primary site could not be identified. The patient was given a diagnosis of peritoneal metastases with an unknown primary and was referred for chemotherapy. Extraosseous findings on F-18 NaF PET/CT, like the one described here, though rare, may be visualized and may result in important management changes, if it is a metastatic site as in our case. However, confirmation with histology or other imaging modality should be made.
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Conflicts of interest
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REFERENCES
- Newer PET application with an old tracer: Role of 18F-NaF skeletal PET/CT in oncologic practice. Radiographics. 2014;34:1295-316.
- [Google Scholar]
- SNM practice guideline for sodium 18F-fluoride PET/CT bone scans 1.0. J Nucl Med. 2010;51:1813-20.
- [Google Scholar]
- Correlation of inflammation assessed by 18F-FDG PET, active mineral deposition assessed by 18F-fluoride PET, and vascular calcification in atherosclerotic plaque: A dual-tracer PET/CT study. J Nucl Med. 2011;52:1020-7.
- [Google Scholar]
- Dystrophic calcification in muscles of legs in calcinosis, Raynaud's phenomenon, esophageal dysmotility, sclerodactyly, and telangiectasia syndrome: Accurate evaluation of the extent with (99m) Tc-methylene diphosphonate single photon emission computed tomography/computed tomography. Indian J Nucl Med. 2015;30:360-1.
- [Google Scholar]
- Nonosseous, nonurologic uptake on bone scintigraphy: Atlas and analysis. Semin Nucl Med. 2010;40:242-56.
- [Google Scholar]
- Skeletal PET with 18F-fluoride: Applying new technology to an old tracer. J Nucl Med. 2008;49:68-78.
- [Google Scholar]
- Extraosseous accumulation of bone scan tracer (99m) Tc-methylene diphosphonate in a phlebolith. Indian J Nucl Med. 2012;27:42-4.
- [Google Scholar]
- Impact of nonosseous findings on (18) F-NaF PET/CT in a patient with ductal breast carcinoma. Nucl Med Mol Imaging. 2014;48:72-4.
- [Google Scholar]
- Intense 18F-fluoride accumulation in liver metastases from a neuroendocrine tumor after peptide receptor radionuclide therapy. Clin Nucl Med. 2012;37:e82-3.
- [Google Scholar]
- Concentration of Tc-99m MDP in ovarian carcinoma and its soft tissue metastases. Clin Nucl Med. 1991;16:550-2.
- [Google Scholar]
- F-18 fluoride uptake in calcified extraosseous metastases from ovarian papillary serous adenocarcinoma. Clin Nucl Med. 2012;37:e22-3.
- [Google Scholar]