ABSTRACT
Osteosarcoma (OS) is a malignant tumor in which osteoid or bone is produced directly by tumor cells. Some OS cells are positive for cytokeratin (CK) and epithelial membrane antigen by immunohistochemistry (IHC) and this may lead to a misdiagnosis of metastatic carcinoma, particularly when the tumor location is unusual. On the other hand, gastrointestinal metastasis of OS is rare. We present the case of a 67-year-old Japanese man with a small intestinal intussusception due to metastasis of a CK-positive rib OS. The tumor cells were positive for CK, osteopontin and osteonectin by IHC and a diagnosis of a CK-positive chest wall OS metastasizing to the small intestine was considered. Osteoid or bone formation was histologically absent and therefore chest wall OS had to be differentially diagnosed from metastatic carcinoma of unknown origin. A postmortem histological analysis confi rmed a rib OS. Awareness of CK-positive OS is important for making a correct diagnosis and for disease management and an immunohistochemical analysis of the tumor for expression of osteopontin and osteonectin may be used to support the diagnosis. In addition, this case shows that rib OS can metastasize to the gastrointestinal tract, albeit rarely, which may induce an intestinal intussusception.
ABSTRACT
A 57-year-old Japanese man visited our hospital with a moist cough. Chest radiographic imaging showed a left hilar shadow. Adenocarcinoma cells were found on cytologic screening of fresh sputum. Although multiple metastases including brain were detected, no tumor was observed in the kidneys. The patient underwent whole-brain irradiation and chemotherapy for advanced-stage lung cancer. One month before his death, carcinomatous meningitis was detected. Hyponatremia, hypo-osmolality, and hypertonic urine suggested the syndrome of inappropriate antidiuresis. Restricting water intake improved the hyponatremia; however, he developed fever and hematuria. Despite systemic administration of an antibacterial drug, he died. Primary tumor in the lung was absent, but adenocarcinoma of the right kidney was evident on autopsy. Lectin histochemical analysis of the carcinoma revealed its distal nephron origin, confirming collecting duct carcinoma. Severe carcinomatous meningitis, which is possibly caused the syndrome of inappropriate antidiuresis, was observed, with no cancer involvement of the pituitary gland and hypothalamus.
ABSTRACT
A patient with malignant pleural mesothelioma was admitted with atrial fibrillation. Chest computed tomography showed a huge mediastinal tumor adjacent to the heart. Autopsy revealed a 12 × 9.5 -cm mediastinal mass involving the right lung, which distorted and stretched the myocardial sleeve surrounding the right inferior pulmonary vein. This case demonstrates that advanced malignant pleural mesothelioma can cause atrial fibrillation, possibly by stimulating myocardium around a pulmonary vein.