Thymic mucosa-associated lymphoid tissue lymphoma associated with bilateral orbital pseudotumor

Thymic mucosa-associated lymphoid tissue lymphoma involving lymph nodes

INTRODUCTION

Thymic mucosa-associated lymphoid tissue (MALT) lymphoma involving lymph nodes is quite rare with only 13 previous cases reported in the literature.

PRESENTATION OF CASE

The 33-years-old female was referred to our department for the investigation of abnormalities on computed tomographic (CT) scans. CT scans showed a 9-cm×3-cm mass composed of a mixture of soft tissue and fat at the anterior mediastinum with lymphadenopathy in the neck, axillary and mediastinal regions. She was underwent complete surgical resection of the mass with regional lymph node dissection through a median sternotomy. Histological examination of the surgical specimens confirmed the diagnosis of MALT lymphoma arising in the thymus with nodal metastasis. She achieved complete remission after postoperative rituximab combined chemotherapy.

DISCUSSION

Thymic MALT lymphoma occurs most frequently in Asian female aged 40-60 years and commonly appears anterior mediastinal masses on CT scans. The excised tissue is necessary to confirm the accurate histological diagnosis. The disease usually remains localized for a long time, making local surgical resection highly effective. However, when the lymph nodes are involved, effective treatment approaches of the disease is still undefined.

CONCLUSION

We report a case of thymic MALT lymphoma involving lymph nodes, in which the patient was successfully treated with primary site resection with regional lymph node dissection followed by rituximab combined chemotherapy. Surgery provided not only a useful approach for collecting tissue for an accurate histological diagnosis, but also an effective local treatment, even in the case of advanced-stage thymic MALT lymphoma.

Primary MALT-type lymphoma of the thymus: a clinicopathological and immunohistochemical study of six cases

BACKGROUND

Six cases of primary extranodal marginal zone B-cell lymphoma of the thymus (MALT [mucosa-associated lymphoid tissue]) are described.

METHODS

The patients were all women between 48 and 59 years. Clinically, all patients, except for one, were Caucasians. Two patients had a history of autoimmune disease, while one was being investigated for such a possibility. The remaining three patients did not have a history of autoimmune disorders.

RESULTS

In those patients who had symptoms related to their anterior mediastinal masses, nonspecific symptoms, including shortness of breath and chest pain, predominated. Histologically, the tumors had the classical morphologic features of cystic and solid areas with an atypical monocytoid cellular proliferation. Immunohistochemical stains performed in all cases showed kappa monotypic expression and B-cell phenotype.

CONCLUSIONS

The current cases highlight that MALT lymphomas of the thymus can occur in a setting not related to autoimmune disease or in those not of Oriental ethnic background and that mediastinal cystic lesions require proper sampling in order to adequately evaluate the possibility of MALT lymphoma.