Mucosa-associated lymphoid tissue lymphoma of the parotid gland - a case report.

Mucosa-associated lymphoid tissue (MALT) lymphoma of the parotid gland is a rare entity among head and neck tumours. We report a case of a patient with a medical history of diffuse large B-cell Non-Hodgkin Lymphoma with complete remission following chemotherapy, who presented seven years afterwards with a progressive painless hard swelling of the right parotidgland. Ultrasonography followed by contrast-enhanced MRI features was consistent with a malignant tumour. Consequently, fine and core needle aspiration biopsy were performed under ultrasound guidance and the final histopathological result was MALT lymphoma of the parotid gland. The most important particularity of the case is the sequential development of two different histopathological types of Non-Hodgkin Lymphoma, both of B-cell lineage.