Chronic expanding hematoma: mystery or misnomer?

Abstract

243 Chronic Expanding Hematoma: Mystery or Misnomer? In a recent issue of AJR , Hwang et al. [1] described a unique pathologic process named as chronic expanding hematoma. As they correctly pointed out, most patients, particularly Japanese patients, developed a lesion in chronic tuberculous empyema [1–5]. Although long-standing growing hematoma has frequently been reported in patients with no history of hemophilia or other hemorrhagic diatheses, the concept of “chronic expanding hematoma” has been criticized. Bleeding episodes caused by vascular lesions of tuberculosis have been well described [6–8]. Aneurysm of the pulmonary artery may occur in the tuberculous cavities and may bleed massively (Rasmussen’s aneurysm) [8]. Thrombosis also occurs in branches of the pulmonary artery around the tuberculous foci (endarteritis obliterans), and the occlusion of pulmonary circulation results in the development of collateral systemic circulation through bronchial, intercostal, and other arteries in the chest wall [6]. Such collateral circulation may become the site of recurrent bleeding [9, 10]. Arteriographically, hypervascularity and enlarged vessels are common findings, and pseudoaneurysm is also seen in a small number of patients [9]. Aneurysms in unusual sites, including the internal mammary artery and aorta, have been reported [11, 12]. Vascular changes in chronic tuberculous empyema have been investigated at pathology and on CT scans [13, 14]. Increased vascularity and even angiomalike changes have been found in the empyema wall [14] (Fig. 1). In addition, we occasionally see active bleeding during percutaneous biopsy through the empyema. However, in the literature dealing with chronic expanding hematoma, the descriptions of the vascular changes are deficient, and in particular, arteriographic findings have not been documented [1–5, 15, 16]. Chronic expanding hematomas may also occur in the extremities [3, 15, 16]. Preexisting conditions including infection, history of surgery, or episodes of trauma are involved in most reported cases, but information on the arteriographic assessment is not available. Autonomic growth of subdural hematoma due to neomembrane formation by blood breakdown products has been shown experimentally [17], but it is not certain whether it is the main cause of extracranial hematoma formation. It is easier to accept hemorrhage due to vascular complications of chronic tuberculous infection as cause for a growing hematoma rather than primary chronic expanding hematoma, particularly for those who are familiar with chronic tuberculous infection. The possibility of a vascular complication of a preexisting condition, if one is present, should be considered for treatment of a growing hematoma. Shigeru Ehara Iwate Medical University School of Medicine Morioka 020-8505, Japan