Rituximab plus CHOP as an initial chemotherapy for patients with disseminated MALT lymphoma

Rare Pulmonary Metastasis From Thyroid Mucosa-Associated Lymphoid Tissue Lymphoma

Primary pulmonary lymphomas constitute up to 1% of all pulmonary malignancies. Patients with mucosa-associated lymphoid tissue (MALT) lymphoma represent approximately 90% of patients with primary pulmonary lymphoma. Most pulmonary MALT lymphomas are primary tumors. Pulmonary metastasis is extremely rare. A 65-year-old woman was diagnosed with a thyroid MALT lymphoma in 2008 and underwent total thyroidectomy, followed by chemotherapy. After 5 years of follow-up, she referred to our hospital with an abnormal shadow on a chest roentgenogram. She underwent video-assisted thoracoscopic surgery and was diagnosed with metastatic thyroid MALT lymphoma. Postoperatively, she was treated with chemotherapy, including rituximab, and is alive without recurrence.

Stage IV intramucosal gastric marginal zone B cell lymphoma of mucosa-associated lymphoid tissue type

A 45-year-old woman with no symptoms underwent upper gastrointestinal endoscopy. A discolored area was noted at the greater curvature of the gastric upper body. Endoscopic ultrasonography demonstrated thickening of the second sonographic layer indicating that the depth of invasion was confined to the mucosa. A urea breath test and anti-Helicobacter pylori antibody test were negative. A computed tomography scan showed a consolidation at the right lung. Gastric biopsy and transbronchial lung biopsy (TBLB) demonstrated a monotonous proliferation of atypical small lymphocytes. A diagnosis of gastric marginal zone B cell lymphoma of mucosa-associated lymphoid tissue type (MALT lymphoma) was made. The clinical stage was stage IV. A genetic analysis showed rearrangement of the joining region of the immunoglobulin heavy chain gene and identical clones in both lesions. An API2-MALT1 fusion gene was detected in the gastric lesion. After H. pylori eradication treatment, combination treatment with rituximab plus CHOP (R-CHOP) was performed; 6 months later an endoscopy revealed complete disappearance of the lesion. Multiple gastric biopsies showed no infiltrating atypical lymphocytes. Similarly, the lesion in the lung showed complete remission (CR) on CT and TBLB. This report shows that a gastric MALT lymphoma located in the mucosa and disseminated to the lung maintained CR by R-CHOP.