A case of a metastatic SDHA mutated paraganglioma re-presenting 23 years after initial surgery. DOI: 10.1530/ERC-17-0206

Abstract

Dear Editor, We have read with great interest the recent article by Tufton and coworkers reporting on the risk of metastasis in patients with paraganglioma (PGL) tumours associated with germline SDHA mutations (Tufton et al. 2017). Herein, we report a further case of a malignant PGL in a 46-year-old man with a succinate dehydrogenase complex flavoprotein subunit A (SDHA) germline mutation (c.91C > T, p.Arg31*). In the case we describe, following the initial surgical removal of a left-sided retroperitoneal PGL, twenty-three years elapsed before the development of a bony metastasis in the eighth left rib. This observation is similar to that of Tufton and coworkers who reported two patients, who developed metastatic disease in 16 and 37 years, respectively, following initial diagnosis (Tufton et al. 2017). During investigations for this case, we found that the rib metastasis was avid on 18-fluorodeoxyglucose (FDG) positron emission tomography (PET) computed tomography (CT), but not avid on radiolabeled I131 metaiodobenzylguanidine (MIBG) imaging (Fig. 1). This observation of SDHA-related malignant PGL is in keeping with SDHB- and SDHD-associated PGL, in which reduced avidity on MIBG imaging is due to reduced tumoural expression of noradrenaline transporters (Timmers et al. 2007). This clinical report supports the recent literature that suggests a risk of malignancy in patients with SDHA mutated PGL (Bausch et al. 2017, Casey et al. 2017, Tufton et al. 2017). The prolonged time interval between diagnosis and development of metastases in our case suggests that SDHA-related tumours are slow growing but it does support long-term surveillance programmes for patients with germline SDHA mutations.