Concurrent lung squamous cell carcinoma and extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue type.

The coexistence of primary lung cancer and lymphoma is a rare finding. We present a case of a 66-year-old woman with marginal B-cell lymphoma of mucosa-associated lymphoid tissue type with lung, mediastinal lymph node, and bone marrow involvement. Surveillance imaging after treatment for lymphoma revealed persistent uptake by positron emission tomography scan. A transbronchial biopsy revealed the marginal B-cell lymphoma and a well-differentiated invasive squamous cell carcinoma. Management was changed to address new pathologic findings.