[Thyroid metastasis of lobular breast carcinoma].

The thyroid gland is an uncommon site for distant metastases from extra-cervical tumors. Malignant melanoma and kidney, lung, breast, and gastrointestinal carcinomas are the most common origins of these rare metastases. We report the case of a patient with rapidly progressive thyroid metastasis from a lobular breast carcinoma operated on three years previously. An 83-year-old female patient underwent surgery in 2007 for a breast tumor by left radical mastectomy and axillary lymphadenectomy. The pathological report confirmed a grade 2, infiltrating lobular carcinoma 5 cm× 4.5 cm× 4.5 cm in size with no involvement of surgical margins and no tumor infiltration in resected lymph nodes (pT2N0). Estrogen receptor expression was 20% and progesterone expression was 5%. Treatment was therefore started with aromatase inhibitors. Subsequent oncological monitoring showed no tumor recurrence. Three years after surgery, the patient experienced for one month a progressive dyspnea which worsened in a supine position, with no cough, expectoration, or fever. She reported a parallel neck enlargement with cervical tightness. Chest X-rays performed in the emergency room showed no evidence of cardiopulmonary disease, but a tracheal displacement suggesting goiter. Computed tomography (CT) of the neck was therefore performed. The CT scan confirmed the presence of a large multinodular goiter with severe tracheal stenosis (Fig. 1), after which the patient was referred to the endocrinology outpatient clinic. At the clinic, the patient showed stridor with advanced respiratory difficulty. In a neck examination, a goiter of hard consistency, immobile on swallowing, and with no cervical adenopathies was palpated. The patient reported having had goiter since a young age, but it had never been studied. Thyroid function was normal, with a TSH level of 0.82 IU/mL (0.27--4.2) and a free T4 level of 1.28 ng/dL (0.93--1.71). Because of rapid goiter growth and symptomatic tracheal compression, urgent surgery was decided upon. During surgery, only left hemithyroidectomy plus istmectomy could be performed because the contralateral lobe was found adhered to adjacent structures with gross tracheal infiltration. Dyspnea subsided after surgery. Pathological analysis of the specimen revealed thyroid metastatic infiltration by a lobular breast carcinoma (Fig. 2). Two week after thyroidectomy, the patient attended the emergency room for anuria over the previous 24 h. A CT scan of the abdomen showed a big pelvic mass compressing both ureters with significant bilateral hydronephrosis. Nephrostomy was performed, and the patient was admitted to the oncology ward. In addition to pelvic mass, hepatic and bone metastases were found, with no evidence of local recurrence. The patient died one month after surgery.