The value of 18F-fluorodeoxyglucose positron emission tomography combined with computed tomography in the detection and characterization of soft tissue metastasis

Abstract

Abstract. Metastatic tumours presenting as soft tissue metastasis (STM) are relatively rare. STM represents metastasis to the muscle and subcutaneous tissues. The majority of the currently available clinical or radiological data on STM consist of isolated case reports or reviews. The aim of this study was to report the manifestations, origin and distribution of STM detected by 18 F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) and to assess the value of 18 F-FDG PET/CT in the characterisation of STM. We reviewed 17 cases of patients with STM who underwent 18 F-FDG PET̸CT scanning. The imaging and clinical data of these patients were retrospectively analysed. This method is very sensitive in the detection of STM and provides ample information for clinical tumour staging. PET is more sensitive compared to CT in detecting lesions in muscle, before the density and morphology of the soft tissues are altered, providing a clear view within the soft tissue. Due to the limitations in resolution, PET is less sensitive compared to CT in detecting lesions in the subcutaneous tissues. The aim of this study was to improve our knowledge of 18 F-FDG PET̸CT findings in the diagnosis of STM and determine its value in the staging of malignant tumours.

Prevalence, distribution, and clinical characteristics of hemangiosarcoma‐associated skeletal muscle metastases in 61 dogs: A whole body computed tomographic study

“…In human medicine, positron emission tomography (PET) has been described for detecting SMMs . In a recent study in humans, the detection rate of SMMs by PET was 100% (51/51), whereas that of CT was 23.5% (12/51) . 18 F‐fluoro‐2‐deoxyglucose ( 18 F‐FDG)‐PET‐CT provides information otherwise not obtainable using conventional diagnostic tools, potentially improving the quality of staging and management of dogs with cancer .…”

Imaging features and prognostic value of 18F-FDG PET/CT detection of soft-tissue metastasis from lung cancer: a retrospective study

“…Other distant organ metastases were considered "positive" if their 18 F-FDG uptake was greater than that of surrounding healthy tissue, or/and if abnormal density changes were noted. Combined with the literature [1,3,5,13,14,17,32], the final diagnostic criteria of STM and other distant organ metastases were histopathological or clinical evaluation (presence of symptoms or diffuse distribution of lesions), concordance between PET/CT results and those of other imaging methods (MRI or contrast-enhanced CT), and evidence of simultaneous remission/progression of primary and metastatic lesion on follow-up PET/CT or other imaging (MRI or contrast-enhanced CT). The patients were followedup until September 2019.…”

“…Soft-tissue metastasis (STM) refers to the growth of tumor cells in soft tissue that is not connected to the primary tumor or regional lymph nodes, and comprises metastases to skeletal muscle and subcutaneous tissue [3][4][5]. Although skeletal muscle and subcutaneous soft tissue account for more than 50% of the human body weight, STM is relatively rare [3][4][5].…”

“…Soft-tissue metastasis (STM) refers to the growth of tumor cells in soft tissue that is not connected to the primary tumor or regional lymph nodes, and comprises metastases to skeletal muscle and subcutaneous tissue [3][4][5]. Although skeletal muscle and subcutaneous soft tissue account for more than 50% of the human body weight, STM is relatively rare [3][4][5]. Factors such as changes in local blood flow, presence of various proteases and inhibitors, high partial pressure of oxygen, changes in pH, pressure, and temperature, and local production of lactic acid are not conducive to the growth of tumor cells, making the soft tissue relatively resistant to the malignant penetration [4,[6][7][8][9][10][11][12].…”

“…Lung cancer is the most common primary tumor of STM, with adenocarcinoma being the most frequent histological variant [13][14][15][16][17][18][19][20]. The most common sites of distant metastasis of lung cancer include the bones, brain, adrenal glands, and liver, with the STM being much less common [3][4][5]. Usually, when lung cancer progresses to a certain extent, some of the tumor cells break away from the primary tumor and disseminate to remote sites through the bloodstream or lymphatic system [21][22][23].…”