Endocrine Abstracts

Case: A 40-year-old woman presented in 04/2015 with pain in the upper abdomen and a history of paroxysmal tachycardia. Plasma normetanephrines were highly elevated. Imaging revealed a large retroperitoneal tumor (15×12×8 cm), which could be completely resected after pre-treatment with urapidil. Histology confirmed diagnosis of a paraganglioma. Genetic diagnostics detected a previously unknown mutation in intron 2 of the SDHB-gene (c.200+5G>C). Six month after initial surgery, plasma normetanephrines increased and imaging showed a single liver metastasis, which was successfully resected. A further five month later, increasing normetanephrine levels and MR-imaging indicated pulmonary, osseous and lymphatic metastatic spread. According to the recommendation of our multidisciplinary tumor board, palliative chemotherapy with monthly administrations of cyclophosphamide, vincristine and dacarbazine (CVD) was initiated in 05/2016, complemented by two peptide-receptor radiotherapies (PRRT) with ¹⁷⁷Lu-DOTATATE in 09/2016 (6.03GBq) and 03/2017 (6.8GBq). Follow up in 11/2016 and 02/2017 revealed a significant reduction of metastases. Normetanephrine levels normalized and remained stable. Due to considerable bone marrow toxicity, both therapies had to be stopped after ten cycles of CVD in spring 2017. Quarterly staging images during follow up showed further regression of metastases, which were no longer detectable in MRI since 09/2018.

Conclusions: Malignant paragangliomas are rare and evidence for treatment of patients with metastases is very limited. Studies available show a rather moderate response to chemotherapies as well as radiotherapeutics. We report the encouraging case of a complete, ongoing remission of an initially rapid progressive malignant paraganglioma under multimodal treatment with CVD and PRRT. Considerable side effect was a, yet reversable, bone marrow toxicity.