Amyloid myopathy: expanding the clinical spectrum of transthyretin amyloidosis-case report and literature review.

We identified two patients with transthyretin (ATTR) amyloid myopathy (one ATTR variant amyloidosis, ATTRv; one wild-type ATTR amyloidosis, ATTRwt). Myopathy was the initial manifestation in ATTRwt, whereas it followed neuropathy and cardiomyopathy in ATTRv. The ATTRwt patient showed muscular tracer uptake on 99mTc-DPD planar scintigraphy at the time of initial diagnosis, consistent with ATTR amyloid myopathy. The ATTRv patient underwent heart transplantation because of progressive heart failure. Within the next two years, progressive myopathic symptoms and extracardiac tracer uptake on 99mTc-DPD planar scintigraphy were documented, attributable to ATTR amyloid myopathy. Interstitial amyloid deposits were confirmed by muscle biopsy in both patients, with a particularly high amyloid burden in the adipose tissue. This case report highlights the frequent concomitant presence of cardiac ATTR amyloidosis and ATTR amyloid myopathy. ATTR amyloid myopathy may precede cardiac manifestation in ATTRwt or occur after heart transplantation in ATTRv. Due to the high diagnostic accuracy of 99mTc-DPD scintigraphy for detecting ATTR amyloid myopathy and the emergence of novel therapeutics, it is important to increase the awareness of its presence.

Detection rate of unknown primary tumour by using somatostatin receptor PET/CT in patients with metastatic neuroendocrine tumours: a meta-analysis.

PURPOSE: The high diagnostic performance of somatostatin receptor positron emission tomography with computed tomography (PET/CT) in neuroendocrine tumours (NETs) was demonstrated by several articles. However, only some studies evaluated the detection rate (DR) of this imaging method in patients with metastatic NETs and unknown primary tumours (CUP-NETs). Therefore, we aimed to perform a meta-analysis to add evidence-based data in this setting. METHODS: A comprehensive computer literature search of studies listed in PubMed/MEDLINE, EMBASE, and Cochrane library databases through December 2018 and regarding the use of somatostatin receptor PET/CT in patients with CUP-NETs was carried out. Pooled DR of CUP-NETs by using somatostatin receptor PET/CT was calculated. A pooled analysis evaluating the percentage of change of management by using somatostatin receptor PET/CT in these patients was also performed. RESULTS: Twelve studies on the use of somatostatin receptor PET/CT in detecting CUP-NETs in 383 metastatic patients were included. The meta-analysis of all these studies provided the following DR on a per patient-based analysis: 56% (95% confidence interval (95% CI): 48-63%). Moderate heterogeneity among the selected studies was found (I2 = 50%), whereas a significant publication bias was excluded by Egger's test (p = 0.45). The most common primary tumour sites were the bowel and the pancreas. A change of management by using somatostatin receptor PET/CT was demonstrated in 20% (95% CI: 10-33%) of patients with CUP-NET. CONCLUSIONS: Somatostatin receptor PET/CT is very useful in detecting CUP-NETs in patients with metastatic disease. More studies on the change of management by using this imaging method in this setting are needed.

Role of positron emission tomography in thyroid and neuroendocrine tumors.

Positron emission tomography (PET) is an established imaging method in oncology. PET/computed tomography (PET/CT) and PET/magnetic resonance imaging (PET/MRI) are hybrid techniques which combine morphological information obtained by CT and MRI with functional data provided by PET. Several PET radiotracers evaluating different metabolic pathways or receptor status can be used to assess endocrine tumors such as thyroid tumors or neuroendocrine neoplasms (NENs). This review is focused to describe the role of PET imaging using different radiotracers in patients with thyroid tumors and NENs. The role of PET imaging with different radiotracers in several endocrine tumors including thyroid tumors, gastroenteropancreatic neoplasms, lung neuroendocrine neoplasms, pheochromocytomas and paragangliomas, and multiple endocrine neoplasia syndromes has been described. Fluorine-18 fluorodeoxyglucose (18F-FDG) PET evaluating the glucose metabolism provides useful diagnostic and prognostic information in patients with thyroid tumors. Iodine-124 (124I) assessing the iodine metabolism may be used for dosimetry and diagnostic purposes in thyroid tumors. In patients with NENs specific radiotracers can be used for diagnostic purposes such as somatostatin analogues labeled with gallium-68 (68Ga-DOTA-peptides) evaluating somatostatin receptor expression and fluorine-18 fluorodihydroxyphenylalanine (18F-FDOPA) assessing the uptake, decarboxylation and storage of amine precursors. One advantage of 68Ga-DOTA-peptides PET is to select patients with well-differentiated and inoperable NENs for peptide receptor radionuclide therapy. 18F-FDG PET may provide useful prognostic information in patients with high-grade NENs. PET imaging with different radiotracers is a useful functional imaging technique in the work-up of several endocrine tumors.