Uncommon first diagnosis of metastatic papillary thyroid carcinoma with “signet-ring” cells morphology through pericardial effusion

Malignant pericardial effusion is a usual and crucial exacerbation in malignancies. In some cases, pericardial effusion may be the first manifestation of the disease. Neoplastic pericarditis is extremely rare in thyroid cancer. Hereby, we describe the case of a 54-year-old man submitted to the hospital for chest pain and dyspnea. Clinical and radiological examinations were suggestive of pericardial effusion and mediastinal lymphadenopathy. The patient underwent pericardial drainage and surgical biopsy of a paratracheal lymph node. Pericardial biopsies were also taken. Histology study was compatible with metastatic papillary thyroid carcinoma with “signet-ring” cell morphology. Extended study of thyroid gland and function was performed and he was referred to oncologists for further treatment.