Endocrine Abstracts

Introduction

Hashimoto’s thyroiditis (HT) has been linked to papillary carcinoma of the thyroid, Hurthle cell cancer or even lymphoma. In contrast, there are only a few reports of co-existence of HT with medullary thyroid carcinoma. The link between them is unknown. An overall prevalence of medullary carcinoma of only 0.35% has been reported in HT patients. This prevalence is higher in female rather than male. We present the case of a female patient treated for Hashimoto’s Disease that was diagnosed with medullary thyroid carcinoma during her routine medical appointment with the endocrinologist.

Case description

The patient, female of 45 years first came with headache, hair loss and extreme fatigue. She was diagnosed previously with chronic thyroiditis and was under treatment with Levothyroxine. Her physical examination did not reveal anything in particular. Her blood tests were as followed: CEA 126 ng/ml (<6.3), Calcitonin > 2000 pg/ml (<10), TG 64, TSH 14.58 (0.3–4.5), fT4 14.04 (9–20), TPO antibody 874.6 (0–30) and TG antibody 2229 (<115). Other laboratory tests were within normal range. Neck ultrasound revealed: the thyroid gland had heterogeneous hypoechoic structure, aspect HT. In the right lobe, it was evident a nodule, isoechoic, taller than wide, with dimensions 2.44 × 2.16 × 1.9 cm, with diffuse micro calcifications inside. Schinti scan with TC99 revealed a cold nodule in the right thyroid lobe. Patient’s past medical history: was unremarkable, without neck irradiation. Family history: without thyroid diseases. The patient underwent total thyroidectomy and lymph nodes dissection. Histopathological examination of total thyroidectomy specimen revealed Hashimoto’s thyroiditis along with medullary thyroid carcinoma, oncocytic variant inside the nodule. She was discharged from the hospital under thyroid hormone replacement treatment. A month after surgery, Calcitonin and CEA levels dropped sharply. Their measurements were repeated after 3, 6, 9, 12 months and resulted normal. The patient continues to be under endocrinologist’s follow up, euthyroid and cancer-free.

Conclusion

The prevalence of the co-existence of Hashimoto’s thyroiditis and medullary thyroid carcinoma is low and rarely described. It is important to know this, in order to be diagnosed and treated in time.