Mucosa-associated lymphoid tissue (
MALT) lymphomas occur in a variety of organs, including the orbit, conjunctiva, salivary glands, skin, thyroid gland, lungs, stomach, and intestine. These
tumors are often localized and of indolent clinical behavior. Diagnosis is made by pathologic evaluation of a tissue biopsy. Careful staging is mandatory and tailored to the initial presentation. Staging includes a history and physical, chemistries, computed tomography scan, and bone marrow biopsy. This information is supplemented with an ear, nose, and throat consultation, esophagogastro-duodenoscopy, colonoscopy, endoscopic ultrasound of the stomach, and cytogenetic/immunohistochemical analysis of the
tumors. Treatment is tailored to organ involvement and stage at presentation. Eradication of Helicobacter pylori using a triple anti-H. pylori regimen approved by the US Food and Drug Administration is standard
therapy for all H. pylori-positive gastric
MALT lymphomas. Endoscopic ultrasound- and computed tomography-staged gastric MALT stage IE
tumors will achieve a complete response with this approach in approximately 60% to 90% of patients (the more superficial the
tumor, the better the response). Patients with
tumors that are T4 node-positive Musshoff stage IIE1 and IIE2 or
tumors with adverse cytogenetics should receive
radiotherapy or surgery with or without
radiotherapy.
Tumors with a significant high-grade component or large cell
tumors with a minor low-grade MALT component should receive CHOP (
cyclophosphamide,
doxorubicin,
vincristine, and
prednisone)-based
chemotherapy. Localized
MALT lymphomas of the orbit, conjunctiva, salivary glands, and thyroid gland are treated successfully with
radiotherapy. Surgery as first-line
therapy for gastric
MALT lymphomas was replaced by attempts at organ preservation. In the past, margin-free surgical excision or
tumor debulking followed by
radiation therapy and
chemotherapy has been highly effective for gastric
MALT lymphomas. Therefore, surgical excision of large cell or bulky
tumors of the stomach, thyroid, lung, and salivary gland, followed by
adjuvant radiotherapy or
chemotherapy, may still be an important consideration in selected patients. Surgery still has a role for patients with relapsed or refractory low-grade disease and life-threatening
hemorrhage. Disseminated
MALT lymphomas are incurable and are treated primarily with
chemotherapy according to symptoms.