Endocrine Abstracts

JOINT2915

Introduction: Thyroid and breast cancers are among the most common cancers, but their coexistence, in particular the association of medullary thyroid carcinoma (MTC) and breast cancer, remains relatively unexplored. This case report illustrates a medullary thyroid carcinoma revealed during the post-therapeutic follow-up of an operated ductal carcinoma of the breast.

Observation: This is a 57-year-old female patient with a history of breast cancer in her sister. She was operated on 10 years ago for ductal carcinoma of the left breast treated by total mastectomy, adjuvant chemotherapy and radiotherapy. The patient was declared in remission, and annual surveillance was initiated. The evolution was marked by the observation of a cervical mass 2 years ago during a post-treatment follow-up consultation. Cervical ultrasound revealed a 22 mm right totolar nodule classified as eutirads 3. A cytopunction was performed and found to be cytologically suspicious of malignancy. The patient underwent total thyroidectomy, the anatomopathology was in favour of a 2.8 cm medullary carcinoma with, on immunohistochemical study, a low-grade MTC with positive calcitonin and negative thyroglobulin. A calcitonin and CEA assay at 6 MONTHS post-op were negative. There were no other components of NME 2

Discussion: The links between CMT and breast cancer are not yet fully understood, but several hypotheses are being explored Although RET mutations have been widely studied in the context of thyroid cancers, several recent studies have suggested that this gene may also play a role in the development of certain types of cancer, including breast cancer. However, the involvement of the RET gene in breast cancer is still in the exploratory phase. It has been suggested that abnormal activation of the RET signaling pathway may contribute to the initiation or progression of certain breast cancers, although this link is less direct than for endocrine cancers. The mechanisms by which RET might contribute to breast cancer probably involve complex interactions with hormone receptors (such as estrogen receptors)

Conclusion: The association between medullary thyroid carcinoma and breast cancer is rare, but deserves special attention in cases where common risk factors, such as genetic mutations, are present