Metastatic primary peritoneal carcinoma presenting as tension hydrothorax

A 66-year-old woman came to the emergency room presenting with progressive dyspnoea and orthopnoea of 3 weeks’ duration. She arrived in acute respiratory distress with pulse oximetry oxygen saturation of 75% in room air and blood pressure of 70/50 mm Hg. The left hemithorax had no breath sounds and was dull to percussion. She was immediately intubated for respiratory failure. A chest radiograph taken after intubation showed large pleural eff usion in the left lung and mediastinal shifting (fi gure A)—fi ndings that are consistent with tension hydrothorax. Tension hydrothorax is a rare but life-threatening disorder, which can be the initial presentation of metastatic cancer. Although the disorder has been described in carcinomas of the lung, breast, ovary, and thyroid, patients with primary peritoneal carcinoma usually present with abdominal symptoms and ascites. We did emergent left thoracostomy and removed 1·5 L haemorrhagic fl uid. The patient’s blood pressure immediately increased to 120/82 mm Hg, and a repeat chest radiograph showed the return of mediastinal structures to midline. Pleural-fl uid cytology showed malignant cells with psammoma bodies (fi gure B, magnifi cation ×400). CT of the chest, abdomen, and pelvis showed large ascites and minimum residual pleural eff usion without evidence of a mass lesion. Further examination showed very high serum concentrations of cancer antigen 125 (CA 125) of 83·4 U/mL (normal range 0–35 U/mL). The diff erential diagnosis at this point included metastatic epithelial ovarian cancer or metastatic primary peritoneal carcinoma. The patient was extubated the next day, underwent successful talc pleurodesis, and was discharged on day 7 with follow-up with a medical oncologist. She received carboplatin (area under the curve 5) and 200 mg/m 2 paclitaxel given once every 3 weeks for four cycles and underwent cytoreductive surgery. Overall, the uterus, fallopian tubes, and ovaries were healthy. Histopathological examination showed moderately diff erentiated metastatic adenocarcinoma aff ecting the peritoneum with extensive intralymphatic tumour and many psammoma bodies. The ovarian component of the tumour was confi ned to the surface epithelium with no cortical invasion consistent with primary peritoneal carcinoma. 15 months after initial presentation, the patient remains in stable condition and has a normal concentration of CA 125.