Giant lamellar bodies as a feature of pulmonary low-grade MALT lymphomas

Aims: Giant lamellar bodies (GLBs) are rare pulmonary inclusions, most freq uently described in sclerosing haemangiomas. Following a recent report of t heir presence in a case of pulmonary lymphoma of MALT origin, our aims were to determine their frequency in pulmonary lymphoproliferative disorders, e xamine their structure and investigate their aetiology further. Methods and results: We reviewed a series of 29 pulmonary lymphomas (23 low -grade, six high-grade) and 18 cases of reactive pulmonary lymphoid hyperpl asia. Five of 23 (22%) low-grade lymphomas contained GLBs, 4/4 of which sta ined for surfactant apoprotein A but not for surfactant apoprotein B. No GL Bs were seen in 18 cases of reactive pulmonary lymphoid hyperplasia or six high-grade primary pulmonary lymphomas. Ultrastructural examination reveale d concentrically arranged extracellular material forming roughly spherical structures up to 25 mu m in diameter. The GLBs were often surrounded by foa my cells and cholesterol clefts, supporting an origin, at least in part, fr om products of cell breakdown and surfactant degradation. Conclusion: These findings support the idea that the presence of lamellar b odies is in part due to stasis of products arising from degradation of surf actant, in association with certain types of chronic pulmonary pathology. G iven their absence in reactive pulmonary lymphoid hyperplasia, the presence of GLBs as an epiphenomenon in a pulmonary lymphoid infiltrate should warr ant careful investigation with regard to the diagnosis of low-grade MALT ly mphoma.