OBJECTIVETo study the clinicopathologic features of primary thymic extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT).

METHODSThe clinical and pathologic findings were evaluated in 3 cases of biopsy confirmed thymic MALT lymphoma. The clincopathologic features, treatment and prognosis were discussed and literatures reviewed.

RESULTSOne male and two female patients presented with asymptomatic mediastinal masses with a history of Sjögren syndrome. They were aged 36, 35 and 41 years respectively, and only one patient had B symptoms. Grossly, all three tumors were encapsulated and had multiple variable-sized cysts on cut-surface. Histopathologically, the normal thymic lobular architecture was effaced by abnormal dense lymphoid infiltration. Prominent lymphoepithelial lesions were formed by centrocyte-like cells infiltrating and expanding Hassall's corpuscles and epithelial cyst lining. All cases showed apparent plasmacytic differentiation. Immunohistochemically, the tumor cells were positive for CD20, CD79a, bcl-2 and negative for CD3, CD5, cyclin D1, CD43, CD10, bcl-6, and CD23. The plasma cells showed kappa light chain restriction. Immunoglobulin heavy chain rearrangement in three cases was confirmed by PCR. All patients were at early stage and received routine chemotherapy with or without radiotherapy after surgical removal. All patients achieved complete remission with 24, 18 and 3 months follow-up, respectively.

CONCLUSIONSPrimary thymic MALT lymphoma may be a rare distinctive lymphoma. It can be diagnosed by HE and immunohistochemical study and should be differentiated from reactive lymphoid proliferation, other types of lymphoma and mediastinal thymoma.

Adult ; Antibodies, Monoclonal, Murine-Derived ; therapeutic use ; Antigens, CD20 ; metabolism ; Antineoplastic Combined Chemotherapy Protocols ; therapeutic use ; Cyclophosphamide ; therapeutic use ; Diagnosis, Differential ; Doxorubicin ; therapeutic use ; Female ; Follow-Up Studies ; Gene Rearrangement, B-Lymphocyte, Heavy Chain ; Humans ; Immunoglobulin Heavy Chains ; genetics ; Keratin-19 ; metabolism ; Lymphoma, B-Cell, Marginal Zone ; drug therapy ; genetics ; metabolism ; pathology ; surgery ; Male ; Prednisone ; therapeutic use ; Pseudolymphoma ; pathology ; Thymus Hyperplasia ; pathology ; Thymus Neoplasms ; drug therapy ; genetics ; metabolism ; pathology ; surgery ; Vincristine ; therapeutic use

Adult ; CD5 Antigens ; metabolism ; Carcinoma, Papillary ; metabolism ; pathology ; Carcinoma, Squamous Cell ; metabolism ; pathology ; surgery ; Choristoma ; metabolism ; pathology ; Diagnosis, Differential ; Female ; Hamartoma ; metabolism ; pathology ; Humans ; Proto-Oncogene Proteins c-kit ; metabolism ; Thymoma ; metabolism ; pathology ; Thymus Gland ; pathology ; Thymus Neoplasms ; metabolism ; pathology ; Thyroid Neoplasms ; metabolism ; pathology ; surgery ; Thyroidectomy ; methods

Adult ; Antigens, CD20 ; metabolism ; Carcinoma ; metabolism ; pathology ; DNA Nucleotidylexotransferase ; metabolism ; Diagnosis, Differential ; Female ; Follow-Up Studies ; Humans ; Keratins ; metabolism ; Lymphoma ; metabolism ; pathology ; Male ; Middle Aged ; Necrosis ; Seminoma ; metabolism ; pathology ; Thymoma ; metabolism ; pathology ; surgery ; Thymus Neoplasms ; metabolism ; pathology ; surgery ; Tuberculosis ; pathology

Child ; Female ; Head and Neck Neoplasms ; diagnosis ; pathology ; surgery ; Humans ; Parathyroid Neoplasms ; diagnosis ; pathology ; surgery ; Thymus Gland ; pathology ; surgery ; Thymus Neoplasms ; diagnosis ; pathology ; surgery

Adenocarcinoma ; diagnostic imaging ; metabolism ; pathology ; surgery ; Carcinoembryonic Antigen ; metabolism ; Diagnosis, Differential ; Follow-Up Studies ; Humans ; Keratin-20 ; metabolism ; Male ; Microfilament Proteins ; metabolism ; Middle Aged ; Phosphopyruvate Hydratase ; metabolism ; Thymus Neoplasms ; diagnostic imaging ; metabolism ; pathology ; surgery ; Tomography, X-Ray Computed

Aged ; CD5 Antigens ; metabolism ; Carcinoma, Basal Cell ; metabolism ; pathology ; surgery ; Diagnosis, Differential ; Humans ; Lung Neoplasms ; pathology ; Male ; Mediastinal Cyst ; pathology ; Middle Aged ; Proto-Oncogene Proteins c-kit ; metabolism ; Thymoma ; pathology ; Thymus Neoplasms ; metabolism ; pathology ; surgery

The association of thymoma with pure red cell aplasia has been well documented, but amegakaryocytic thrombocytopenia is not a recognized paraneoplastic syndrome complicating thymoma. We report a case of thymoma-complicated pure red cell aplasia and amegakaryocytic thrombocytopenia in a 73-yr-old woman. Pure red cell aplasia was diagnosed seven months after the detection of thymoma. One year after the diagnosis of pure red cell aplasia and seven months after thymectomy, bone marrow aspiration and biopsy showed an absence of megakaryocytes, marked erythroid hypoplasia with normal myeloid series. A diagnosis of amegakaryocytic thrombocytopenia and pure red cell aplasia was made. Oral steroid maintenance therapy resulted in recovery of platelet count. She has still transfusion-dependant anemia but platelet and neutrophil counts had been maintained in normal range for more than five months, until the last follow-up. We think that autoreactive T cells may induce a clinical autoimmune response even after eradication of thymoma, and aplastic anemia as a late complication following thymectomy was described in previous cases. This patient also has to be under a close observation because of the possibility to evolve into aplastic anemia.
Aged ; Bone Marrow/pathology ; Female ; Humans ; Imidazoles/therapeutic use ; Megakaryocytes/pathology ; Pregnadienetriols/therapeutic use ; Red-Cell Aplasia, Pure/complications/*diagnosis ; Thrombocytopenia/*diagnosis/drug therapy/*etiology ; Thymectomy/*adverse effects ; Thymoma/*complications/diagnosis/surgery ; Thymus Neoplasms/*complications/diagnosis/surgery

Diagnosis, Differential ; Fibroadenoma ; metabolism ; pathology ; surgery ; Humans ; Keratins ; metabolism ; Lipoma ; metabolism ; pathology ; surgery ; Male ; Middle Aged ; Mucin-1 ; metabolism ; Neoplasms, Multiple Primary ; metabolism ; pathology ; surgery ; Thymoma ; metabolism ; pathology ; surgery ; Thymus Neoplasms ; metabolism ; pathology ; surgery ; Vimentin ; metabolism

Breast metastasis from nonmammary malignant neoplasms is uncommon, and it accounts for approximately 2% of all breast tumors. Distant metastasis of thymoma is very rare, and especially to extrathorcic areas. We report a female who had a metastatic thymoma in her breast 20 years after undergoing resection for a non-invasive thymoma. She presented with a palpable mass in her left breast. Mammography and ultrasonogram showed a lobular mass at the anterior glandular portion. Histological examination after surgical excision revealed a metastatic thymoma.
Breast Neoplasms/diagnosis/*secondary/surgery ; Female ; Humans ; Magnetic Resonance Imaging ; Middle Aged ; Thymoma/diagnosis/*secondary/surgery ; Thymus Neoplasms/diagnosis/*pathology/surgery ; Tomography, X-Ray Computed ; Ultrasonography, Mammary

Adolescent ; Aged ; Antineoplastic Combined Chemotherapy Protocols ; administration & dosage ; Cyclophosphamide ; administration & dosage ; Diagnosis, Differential ; Doxorubicin ; administration & dosage ; Female ; Hodgkin Disease ; pathology ; Humans ; Lung Neoplasms ; pathology ; Lymphoma, B-Cell ; drug therapy ; pathology ; surgery ; Male ; Mediastinal Neoplasms ; drug therapy ; pathology ; surgery ; Mediastinum ; surgery ; Neoplasm Invasiveness ; Precursor Cell Lymphoblastic Leukemia-Lymphoma ; pathology ; Prednisone ; administration & dosage ; Thymoma ; pathology ; Thymus Neoplasms ; pathology ; Vincristine ; administration & dosage