Endocrine Abstracts

Metastases in the thyroid gland are very rare and their true incidence has not been clearly established. There are few reports of metastases to this gland and most of them are not detected in clinical practice.

Although detection of metastases to the thyroid gland usually indicates poor prognosis aggressive surgical and medical treatment in isolated thyroid metastases may be effective as described for renal carcinoma.

Malignant melanoma is one of the tumours which may metastatize to the thyroid gland. We describe the case of a man with a thyroid metastasis form a treated choroidal melanoma incidentally discovered by fine-needle aspiration biopsy.

Case report: An 82-year-old man with an history of choroidal melanoma treated with proton beam radiotherapy four years before, presented with a thyroid nodule of the left lobe, clinically evident since the last two months. Annual hepatic echotomography and semi annual liver enzyme assays evaluated for the oncologic follow up always resulted within the normal range. Thyroid echotmography showed a unique hypoechoic, dishomogeneous richly vascularized nodule of the left lobe of about 2.5 cm in size. No suspected lymphadenopathy was evidenced.

The fine needle aspiration biopsy showed the presence of many epiteliomorphic cells with nuclear atypia and cytoplasmatic pigmentation as for melanin. The lesion was hence consistent with thyroid metastasis form malignant melanoma.

The evaluation of tumour extension with TC showed multiple pulmonary lesions and abdominal lymphadenopathy consistent with metastases.

Discussion: This case is to focus on the need to consider even rare possibilities in the differential diagnosis of thyroid nodules and to stress that an accurate echographic exam of the thyroid gland and cytology are essentials for the diagnosis. It could be hypothesized that in patients with melanoma a more extended follow up would evidence metastatic lesions thyroid more precociously so that a surgical treatment could be essayed.