ISFL The diagnosis of ISFL requires that sensitive immunochemistry methods find that germinal centers but not other sites of involved lymph follicles contain monotonous-appearing or sometimes atypical lymphocytes that strongly express Bcl2 due to a t(13:18)(q32:q21) translocation. Usually, these cells also strongly express CD10 moderately express CD20 and Bcl6, and proliferate slowly as defined by their Ki-67 levels. The follicles often have a reactive, hyperplastic appearance but the follicular mantle as well as the surrounding<unk>  tissue retain an overall normal architecture. ISFL is associated with overt FL that occurs concurrently in the same or other<unk>  tissues in 16-23% of cases. At diagnosis or thereafter, ISFL may also be associated with other<unk>  malignancies including splenic marginal zone lymphoma, CLL/SLL, marginal zone lymphoma, peripheral T-cell lymphoma not otherwise specified, and classical Hodgkin lymphoma. Differential diagnosis ISFL is distinguished form reactive hyperplastic germinal centers by the presence of lymphocytes that expression the markers cited in the previous section, particularly Bcl2. However, ISFL is associated with overt FL that occurs concurrently in the same or other<unk>  tissues in 16-23% of cases. Screening studies such as CT scans and bone marrow examinations are recommended to determine the presence of splenic FL, marginal zone lymphoma, CLL/SLL, marginal zone lymphoma, peripheral T-cell lymphoma not otherwise specified, or classical Hodgkin lymphoma. ISMCL The diagnosis of ISMCL requires that sensitive immunochemistry methods find that the marginal zone of germinal centers of involved lymph follicles contain lymphocytes that strongly express cyclin D1 due to a t(11:14)q13:q32) translocation. These germinal centers typically exhibit reactive hyperplasia. The neoplastic lymphocytes usually also express CD20, SOX11, and immunoglobulin D but usually do not express two markers that are commonly expressed in MCL, CD5 and CD43. The cyclin D1-expressing lymphocytes generally populate the inner layers of the marginal zone but on occasion some of these cells may be identified in the germinal centers surrounded by these marginal zones as well as in the bone marrow. The cells do not disrupt the overall architecture of the involved follicles. At the time of diagnoses, ISMCL is occasionally found to be associated with overt MCL in the same or other tissues and at diagnosis or sometime thereafter may be associated with CLL/SLL, marginal zone lymphoma, and FL. Differential diagnosis ISMCL is distinguished from reactive germinal center hyperplasia by the presence of mantle zone lymphocytes that express cyclin D1 as well as the other markers described above. Screening studies such as CT scans and bone marrow examinations are recommended to determine if MCL, CLL/SLL, marginal zone lymphoma, or FL is present.
In situ lymphoid neoplasia
Benign lymphoepithelial lesion
Germ cell neoplasia in situ
Solitary lymphatic nodule
Intraepithelial neoplasia
Squamous intraepithelial lesion
Ductal carcinoma in situ
Epithelial dysplasia