A rare case of thyroid nodule mimicking carcinoma

G. Wille, G. Stuckmann, S. Breitenstein

Objective

Thyroid nodules are nowadays evaluated with ultrasound and fine needle aspiration. Different criteria such as hypoechogenity, central vascularisation, blurred margins and microcalcifications are related to higher probability of malignancy.

Differential diagnosis include hyperplastic nodule, adenoma and thyroid cancer.

Seldom can systemic diseases such as lymphoma, plasmocytoma or sarcoidosis affect the thyroid gland mimicking a thyroid neoplasia.

Methods

We describe an unusual case of a thyroidectomy due to suspicion of a thyroid carcinoma.

Results

A 45-year-old man presented with enlargement of the thyroid (32 ml) in our outpatient clinic. There were no signs of hypo-, or hyperthyroidism and no abnormalities with regard to respiration, phonation or swallowing. Sonographically two hypoechogenic nodules were identified in the isthmus of the thyroid gland. One of them showed no sonographic signs of malignancy (TIRADS II). While the second nodule (0.9 cm) was highly suspicious for cancer (TIRADS IV c), showing all sonographic features of malignancy. Follicular neoplasia without definitive diagnosis of carcinoma was diagnosed by FNP for the suspicious nodule (Brit. THY 3). An uneventful thyroidectomy was performed. Surprisingly the histopathological evaluation of the nodule showed multiple non-caseating epithelial granulomas in the context of a systemic sarcoidosis with no signs of malignancy. Further evaluation by computed tomography showed enlargement of the mediastinal lymph nodes, a nodular pattern in the left lung and signs of sarcoidosis affecting the heart.

Sarcoidosis as a cause of either diffuse goiter or solitary nodules is very rare. Very few patients have been reported since the original description in 1932. In our case the patient was euthyreot. Although, hypothyroidism with sarcoidosis has been described, hypothyroidism is caused through extensive infiltration by epithelioid granulomas.

Conclusion

Sarcoidosis can affect the thyroid gland with nodule formation mimicking a carcinoma. Following standardized diagnostic procedures, involving clarification of thyroid nodules both through FNP and sonography, can still fail to establish diagnosis.