Cutaneous spreading of parathyroid carcinoma after fine needle aspiration cytology

Background: Ultrasound-guided fine needle aspiration cytology (FNAC) of suspect parathyroid adenomas is sometimes used for the diagnosis of primary hyperparathyroidism (PHPT). FNAC complications are rare or mild. We describe the first case in literature of cutaneous spread of parathyroid carcinoma after FNAC. Case: A woman underwent a neck ultrasound which revealed a solid hypoechogenic nodule of 1.5 cm at the level of the inferior pole of the right thyroid. In the same time a FNAC of the nodule was performed. Cytology showed no atypical cells. Successively PHPT was diagnosed and a few weeks later the patient had a subcutaneous lump in the same area of FNAC. The patient underwent surgery and histology of the specimen showed a differentiated parathyroid carcinoma. The postoperative course was regular and calcium and parathormone resulted normal. Conclusion: The use of FNAC should be carefully assessed in the presence of suspect parathyroid carcinoma, because this could cause a possible diffusion of a parathyroid carcinoma along the needle tract.