Lung Ball (syn: Mycotic lung sequestrum, primary aspergilloma)

Definition: One outcome of acute, invasive aspergillus pneumonia is a lung ball. Radiographically, it develops when a rounded consolidation cavitates peripherally to yield a central opacity surrounded by a crescent of air. The sequence of events from normal lung to lung ball may occur in as short a time as 2 weeks, and the cavitation coincides with recovery from a neutropenic state. The term lung ball or mycotic lung sequestrum is used to distinguish this lesion from a fungus ball, which represents growth of fungus in a preformed cavity [1].

A review of 38 cases of lung ball indicated that AML was the most common underlying disease (29/38) [2]. Radiographic opacities were first noted when the patient was neutropenic. Lung ball formation occurred an average of 2-16 days after the PMN count recovered [2,3]. In one study, 3 of 11 patients with lung balls developed massive hemoptysis [3]. The mean time from cavitation to hemoptysis was 7 da (1-14) [2]. When measured, platelet counts and clotting parameters were normal [2,3]. Patients were treated with antifungal agents ± lobectomy of the lung ball [2,4].

Gross features: This lung ball crosses the fissure between the RM and RL lobes, a feature seen more frequently in fungal, than in bacterial, pneumonias. The lung ball is a rounded mass of pneumonic lung tissue (a few architectural markings remain) surrounded by an air space. The adjacent lung parenchyma has a thin fibrous layer.

Histologic changes: This small, incipient lung ball (A) shows the central, necrotic lung parenchyma with invasive aspergillus (bluish organisms) pneumonia. The periphery is composed of a thick layer of PMNs that have digested the lung tissue, but a cavity has not yet formed. As a result of the digestion, vessels may be eroded and hemoptysis may occur. At high magnification (B), the PMNs are present at the top, and the necrotizing aspergillus pneumonia is at the bottom. The arrow indicates a branching hypha that has a pink, proteinaceous coat. This pink coating accounts for the dark pink layer of similar hyphae just under the PMNs in A. The nature of this coating, which has been described around fungi and helminth eggs and is called the Splendore-Hoeppli phenomenon, is unknown [5].

AB

References

1. Przyjemski C, Mattii R. The formation of mycetomata. Cancer 1980; 46:1701-1704.

2. Kibbler C, Milkins S, Bhamra A, Spiteri M, Noone P, Prentice H. Apparent pulmonary mycetoma following invasive aspergillosis in neutropenic patients. Thorax 1988; 43:108-112.

3. Albelda S, Talbot G, Gerson S, Miller W, Cassileth P. Pulmonary cavitation and massive hemoptysis in invasive pulmonary aspergillosis. Influence of bone marrow recovery in patients with acute leukemia. Am Rev Respir Dis 1985; 131:115-120.

4. Baron O, Guillaumé B, Moreau P, Germaud P, Despins P, De Lajartre A, Michaud J. Aggressive surgical management in localized pulmonary mycotic and nonmycotic infections for neutropenic patients with acute leukemia: report of eighteen cases. J Thorac Cardiovasc Surg 1998; 115:63-69.

5. Yoshikawa Y, Truong L, Watanabe T. Splendore-Hoeppli phenomenon in bronchocentric granulomatosis. Thorax 1988; 43:157-158.

Clinical summaryDiscussion

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