Pulmonary lymphoma or pseudolymphoma: a diagnostic dilemma.

The clinical significance of pulmonary pseudolymphoma remains unresolved. We report a case which highlights the lymphoma versus pseudolymphoma dilemma. An elderly lady followed up for more than ten years with a slowly enlarging right lung mass had on biopsy, lymphoid hyperplasia consistent with a lymphoma or pseudolymphoma. Laboratory investigations revealed hyperglobulinemia due to a biclonal gammopathy with elevated serum immunoglobulin M and G fractions. Monoclonal production of immunoglobulin is today considered more indicative of a neoplasia than a hyperplasia.