Primary pulmonary mucosa-associated lymphoid tissue lymphoma accompanied by a hydatid cyst.

Pulmonary lymphomas are categorized into 4 groups: primary pulmonary involvement, recurrent or secondary pulmonary lymphoma, post-transplantation lymphoproliferative lymphomas, and lymphomas related to the acquired immune deficiency syndrome.1-3 Primary pulmonary lymphoma (PPL) is a rare entity composing 0.5–1.0% of all pulmonary malignancies and 1.0% of all lymphomas. PPL affects both lobes of the lungs (parenchyma or bronchial) and is described as a clonal lymphoid proliferative disease. In these patients, no mediastinal adenopathy or extrapulmonary involvement occurs. However, extrathoracic involvement is expected during the first 3 months of the follow-up period.4,5 PPL is most commonly known as a non-Hodgkin lymphoma and has been divided into 2 World Health Organization groups: mucosa-associated lymphoid tissue (MALT) and nonMALT. MALT defines the lymphoid tissue located beneath the epithelial tissue that is associated with mucosal immunity.6-9 When lymphoma occurs in the lungs, factors such as smoking, autoimmune deficiencies, and infectious diseases are considered to correlate with the chronic antigenic stimulation of the disease.1,4-6,10,11 Primary pulmonary MALT lymphoma is most commonly seen between the 5th and 7th decades of life and rarely observed before 30 y of age. The disease occurrence has been thought to be similar in both sexes, but recent literature has reported a higher incidence in female patients.7 The symptoms of pulmonary lymphomas include single or multiple nodules, masses, infiltrates, and radiological findings such as consolidation. Primary pulmonary MALT is a very rare disease and, in our case, was accompanied by a hydatid cyst, which is discussed in this report.