[Imaging features of primary pulmonary lymphomas]

Primitive pulmonary lymphomas (PPL) are rare tumors, often misdiagnosed by radiologists.

In order to illustrate the various radiological presentations of PPL, we report a retrospective series of nine cases of PPL collected in our service over a period of four years. A mucosa-associated lymphoid tissue (MALT) lymphoma was found in six patients, a diffuse large B-cell lymphoma in two patients and lymphomatoid granulomatosis in one patient. All diagnoses were proven histologically by bronchial or surgical biopsies.

Among the six cases of MALT lymphoma, computed tomography (CT) demonstrated one or more areas of alveolar consolidation in four patients, progressing with a chronic course over 2 years in two patients. Other CT features were nodular opacities associated with a mass or consolidation and diffuse "ground glass" opacities. In the two cases of diffuse large B-cell lymphoma, CT showed one or more masses spreading locally, mimicking primary bronchial carcinoma. In lymphomatoid granulomatosis the CT showed diffuse interstitial disease with fibrosis.

The imaging features of PPL are very polymorphic. The diagnosis of MALT lymphoma is often difficult because its radiological appearance is often falsely reassuring.