{"entity":{"id":"micronodular-thymoma","kind":"cancer","name":"Micronodular thymoma with lymphoid stroma","aka":["Micronodular thymoma","MNT","Micronodular thymoma with lymphoid stroma (rare, indolent)","Micronodular thymoma with lymphoid stroma (thymoma, thymic-epithelial)"],"tldr":"Micronodular thymoma with lymphoid stroma is a rare, benign-behaving thymoma made of small nests of spindle-shaped epithelial cells separated by abundant B lymphocytes, unlike other thymomas whose lymphocytes are T cells. It is cured by surgery; its curiosity is that a third harbour a clonal B-cell population, and a few develop a low-grade lymphoma within the tumour.","summary":"Micronodular thymoma with lymphoid stroma is an uncommon thymoma variant in the WHO classification, characterised by multiple small nodules of type A thymoma-like cells separated by a B-cell-rich lymphoid stroma with follicles (Histopathology 2015). Monoclonal B-cell populations were found in 6 of 18 cases (33 percent), with an intratumoural lymphoma in three, against consistently polyclonal B cells in thymic follicular hyperplasia and other thymomas; the neoplastic epithelium expresses chemokines that recruit dendritic and B cells, setting the stage for lymphoma (Journal of Pathology 2005). Langerhans cells are abundant within the tumour nests and mature dendritic cells cluster with T cells in the stroma, suggesting how the lymphoid follicles form (Histopathology 2015).\n\nHow it differs from its parent: its lymphocytes are B rather than immature T cells, myasthenia gravis is rare, behaviour is indolent, and the only complication of note is a MALT-type lymphoma arising within it.\n\nHow common: no registry figure; a rare variant (Histopathology 2015).\n\nTreatment: complete resection, which is curative in the reported cases; any associated lymphoma is treated on the MALT lymphoma page; no adjuvant therapy is indicated.","asOf":"2026-09-24","wikipedia":"https://en.wikipedia.org/wiki/Thymoma","links":[{"label":"NCI PDQ: thymoma and thymic carcinoma treatment","url":"https://www.cancer.gov/types/thymus-cancer/thymoma-thymic-carcinoma"},{"label":"Journal of Pathology 2005: micronodular thymoma, abnormal chemokine expression and lymphoma development","url":"https://doi.org/10.1002/path.1808"},{"label":"Histopathology 2015: micronodular thymoma with lymphoid stroma, Langerhans and dendritic cells in six patients","url":"https://doi.org/10.1111/his.12428"}],"tags":["subtype-page","wave4","rare"],"related":["thymoma","thymoma-type-a-ab","thymoma-type-b1-b2","malt-lymphoma","thymic-epithelial"],"cancers":[],"sections":[],"technologies":[],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":[],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"group":"thoracic","burden":"Rare: the two pathology series in the sources read hold 18 and 6 cases (Journal of Pathology 2005; Histopathology 2015). No registry figure exists.","subtypes":["Micronodular thymoma with lymphoid stroma without a clonal B-cell population","Micronodular thymoma with a monoclonal B-cell population (a third of cases)","Micronodular thymoma with an intratumoural MALT-type lymphoma"],"biomarkers":["Type A-like epithelial nests with B-cell-rich stroma and follicles","B-cell clonality (IgH rearrangement)","Langerhans and dendritic cell distribution","Stage (almost always encapsulated)"],"standardOfCare":[{"setting":"All cases","approach":"Complete resection; associated lymphoma treated on the MALT lymphoma page; no adjuvant therapy.","refs":["thymoma","malt-lymphoma"]}],"stateOfArt":[],"history":[],"pipeline":[],"openProblems":[],"parent":"thymoma"},"route":"/cancers/micronodular-thymoma/","neighbours":{"cancer":[{"id":"malt-lymphoma","kind":"cancer","name":"Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma)","route":"/cancers/malt-lymphoma/"},{"id":"thymoma","kind":"cancer","name":"Thymoma (WHO types A, AB, B1, B2 and B3)","route":"/cancers/thymoma/"},{"id":"thymic-epithelial","kind":"cancer","name":"Thymoma and thymic carcinoma","route":"/cancers/thymic-epithelial/"},{"id":"thymoma-type-a-ab","kind":"cancer","name":"Type A and type AB thymoma","route":"/cancers/thymoma-type-a-ab/"},{"id":"thymoma-type-b1-b2","kind":"cancer","name":"Type B1 and type B2 thymoma","route":"/cancers/thymoma-type-b1-b2/"}]}}