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. Clinical presentation and histology are discussed emphasizing the rare correlation between pericardial pathology and metastatic thyroid carcinomas as the first diagnosis. Histopathologic findings of “signet-ring” cell morphology are very challenging for a differential diagnosis between thyroid carcinoma and other metastatic adenocarcinomas

Distant lung metastases caused by a histologically benign phosphaturic mesenchymal tumor

Tumor-induced osteomalacia (TIO) is a rare form of hypophosphatemia usually caused by phosphaturic mesenchymal tumors (PMTs); the biologic behavior of PMTs is under investigation. Herein we present a case of TIO with a protracted course over 12 years leading to a fatal outcome. A 39-year-old man presented with weakness in 2004 and was found to have decreased serum phosphorus, phosphaturia and low levels of 1,25-dihydroxyvitamin D3. Four years later he developed a painful left calf mass. The lesion was resected, but recurred causing extreme pain and dysfunction. Radiological examination showed a large cluster of soft tissue tumors affecting all the muscle compartments of the calf and a smaller lesion inside the metaphysis of the tibia. Above-knee amputation was performed. Histological examination of all lesions showed a cellular spindle cell neoplasm with variously sized vessels, wide vessel-like spaces and scattered deposits of calcified extracellular material. The tumor infiltrated skeletal muscles, subcutaneous fat and the proximal end of the fibula. The tibial lesion had identical histology. Three years after the amputation the patient presented with cough and dyspnea. Radiological examination, followed by an open biopsy, showed that there were multiple metastatic nodules of PMTs in both lungs. Shortly after the diagnosis the patient died. This case illustrates that even benign cases of PMTs may lead to a fatal outcome and the classification of PMTs into benign and malignant should be reassessed in order to correspond to its biological behavior

Distant lung metastases caused by a histologically benign phosphaturic mesenchymal tumor

Tumor-induced osteomalacia (TIO) is a rare form of hypophosphatemia usually caused by phosphaturic mesenchymal tumors (PMTs); the biologic behavior of PMTs is under investigation. Herein we present a case of TIO with a protracted course over 12 years leading to a fatal outcome. A 39-year-old man presented with weakness in 2004 and was found to have decreased serum phosphorus, phosphaturia and low levels of 1,25-dihydroxyvitamin D3. Four years later he developed a painful left calf mass. The lesion was resected, but recurred causing extreme pain and dysfunction. Radiological examination showed a large cluster of soft tissue tumors affecting all the muscle compartments of the calf and a smaller lesion inside the metaphysis of the tibia. Above-knee amputation was performed. Histological examination of all lesions showed a cellular spindle cell neoplasm with variously sized vessels, wide vessel-like spaces and scattered deposits of calcified extracellular material. The tumor infiltrated skeletal muscles, subcutaneous fat and the proximal end of the fibula. The tibial lesion had identical histology. Three years after the amputation the patient presented with cough and dyspnea. Radiological examination, followed by an open biopsy, showed that there were multiple metastatic nodules of PMTs in both lungs. Shortly after the diagnosis the patient died. This case illustrates that even benign cases of PMTs may lead to a fatal outcome and the classification of PMTs into benign and malignant should be reassessed in order to correspond to its biological behavior