Takagi N, Nakamura S, Yamamoto K, Kunishima K, Takagi I, Suyama M, Shinoda M, Sugiura T, Oyama A, Suzuki H
Department of Pathology, Aichi Cancer Center Hospital, Nagoya, Japan.
Cancer. 1992 Mar 15;69(6):1347-55. doi: 10.1002/1097-0142(19920315)69:6<1347::aid-cncr2820690608>3.0.co;2-c.
A 59-year-old woman with Sjögren's syndrome had an anterior mediastinal tumor. The tumor had epithelium-lined thymic cysts. Histologically, centrocyte-like (CCL) cells were present as clusters intermingling with small lymphocytes and plasma cells, invaded the epithelium, and formed characteristic lymphoepithelial lesions; the tumor was identified as malignant lymphoma arising in mucosa-associated lymphoid tissue (MALT). Within the tumor, trapped Hassall's corpuscles were recognized. Immunohistochemical staining demonstrated monotypic cytoplasmic kappa light chains in a small portion of the CCL cells. Furthermore, Southern blot hybridization studies showed rearrangements of immunoglobulin heavy chain, immunoglobulin kappa light chain, and T-cell receptor beta genes. The findings are consistent with thymic low-grade B-cell MALT lymphoma.