Paraneoplastic Hyperthyroidism in an Adult with Choriocarcinoma - A Case Report

Isabel Inacio; Sara Santos; Silva Paulo Dias; Nuno Goncalves; Joaquina Mauricio; Pinto Ricardo Teixeira; Ferreira Ana Vaz; Raquel Calheiros; Pedro Souteiro; Joana Oliveira; Santos Ana P; Isabel Torres

doi:10.1530/endoabs.90.EP972

EP972

Prev Next

Section Contents Cite

Endocrine Abstracts (2023) 90 EP972 | DOI: 10.1530/endoabs.90.EP972

ECE2023 Eposter Presentations Thyroid (128 abstracts)

Paraneoplastic Hyperthyroidism in an Adult with Choriocarcinoma – A Case Report

Isabel Inácio ¹ , Sara Santos ¹ , Paulo Dias Silva ² , Nuno Gonçalves ³ , Joaquina Maurício ⁴ , Ricardo Teixeira Pinto ⁴ , Ana Vaz Ferreira ⁴ , Raquel Calheiros ¹ , Pedro Souteiro ¹ , Joana Oliveira ¹ , Ana P Santos ¹ & Isabel Torres ¹

Err

Author affiliations

¹Portuguese Institute of Oncology of Porto, Endocrinology, Porto, Portugal; ²Portuguese Institute of Oncology of Porto, Clinical Pathology, Porto, Portugal; ²Portuguese Institute of Oncology of Porto, Clinical Pathology, Porto, Portugal; ⁴Portuguese Institute of Oncology of Porto, Oncology, Porto, Portugal

Introduction: Hyperthyroidism is an endocrine condition with multiple causes. Paraneoplastic hyperthyroidism due to marked overproduction of human chorionic gonadotropin (hCG) by choriocarcinoma is a rare diagnosis, which results from the homology of the alpha subunit of hCG to TSH.

Clinical case: A 33-year-old man, with a history of cryptorchidism and orchidopexy in infancy and a euthyroid thyroid nodule, presented with nausea, constipation, and abdominal pain. Computed tomography showed a retroperitoneal mass with 90x77x72 mm and multiple bilateral pulmonary nodules. Laboratory data revealed pancytopenia with neutropenia and hCG levels of 144,690 (<2.5) mUI/ml, and testicular ultrasound was normal. He was admitted with a presumptive diagnosis of extragonadal choriocarcinoma with pulmonary metastases and was started on chemotherapy and corticotherapy. Approximately a week later, the patient presented with respiratory insufficiency and hemoptoic cough likely in the context of haemorrhage from the pulmonary metastasis. He was admitted to the intensive care unit for ventilatory support, requiring an increase in corticotherapy dose. On the ninth day of chemotherapy, laboratory data showed maximum hCG levels of 590,399 mUI/ml. Due to the thyroid function compatible with hyperthyroidism [FT4 7.77 (0.80-1.67) ng/dl, FT3 18.5 (2.00-4.40) pg/mand TSH <0.005 (0.270-4.200) uUI/ml], the treatment with methimazole was started. Later results showed negative anti-TSH receptor, anti-thyroid peroxidase and anti-thyroglobulin antibodies. The patient continued treatment, with a favorable response: on the twenty-first day of chemotherapy, hCG levels dropped to 25,656 mUI/ml, pancytopenia and neutropenia improved, and thyroid function showed FT4 of 2.47 ng/dl and FT3 2.58 pg/ml. Approximately 3 months later, the patient is still on chemotherapy and methimazole, with improved thyroid function [FT4 1.20 (0.80-1.67) ng/dl, FT3 3.15 (2.00-4.40) pg/ml and TSH <0.215 (0.270-4.200) uUI/ml] and significantly lower hCG levels [58.9 (<2.5) mUI/ml].

Conclusion: The treatment of paraneoplastic hyperthyroidism due to hCG is directed against the tumor, however antithyroid medication is a useful adjunctive therapy in a presence of frank and prolonged hyperthyroidism. Chemotherapy, in an initial phase, can cause an even more marked increase in hCG levels, as seen in this case. Since symptoms of hyperthyroidism overlap with those of metastatic disease, is important to evaluate thyroid function in addition to the hCG value.