A Unique Case of Rapidly Progressive Diffuse Pulmonary Nodules

Abstract

The following case report describes a unique presentation of primary malignant fibrous histiocytoma (MFH) originating in the right ventricle. A 71-year-old male presented to the emergency department with tachycardia, dyspnea, tachypnea, and left leg pitting edema, seven weeks following a right total hip arthroplasty. Six weeks prior to presentation, the patient was diagnosed with pulmonary embolism and five pulmonary nodules based on computed tomography (CT) angiography. Laboratory studies at this time indicated anemia of chronic disease, consistent with results from six weeks earlier. Broncho-alveolar lavage (BAL) cytology suggested adenocarcinoma. CT angiography demonstrated a dramatic increase in the amount and extent of the pulmonary nodules previously noted in addition to an unresolved embolus of the right upper lobe. CT-guided biopsy was performed and confirmed a definitive diagnosis of non-small cell lung cancer. Two days after CT-guided biopsy, the patient developed acute hypotension and hypoxic respiratory failure rapidly progressing to asystole and subsequent death. Autopsy revealed a primary intra-cavitary malignant fibrous histiocytoma in the right ventricle, and multiple nodular tumours throughout the lung parenchyma with chest wall invasion. These findings allowed for a revision of the diagnosis and clinical-pathological picture. This case illustrates the limitations of radiological imaging in visualizing vascular structures, and the continued importance of autopsy in achieving a complete and correct pathological diagnosis. Moreover, this case draws light to the unclear diagnostic criteria for MFH and lack of effective treatment options. The longest documented survival of MFH is eight years, which was achieved with orthotopic cardiac transplantation.