# Micronodular thymoma with lymphoid stroma

Source: https://onco.cc/cancers/micronodular-thymoma/  
OnCo record `micronodular-thymoma` (Cancer). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

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).

How 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.

How common: no registry figure; a rare variant (Histopathology 2015).

Treatment: complete resection, which is curative in the reported cases; any associated lymphoma is treated on the MALT lymphoma page; no adjuvant therapy is indicated.

## Fields

- Kind: Cancer
- Last checked: 2026-09-24
- Also known as: Micronodular thymoma; MNT; Micronodular thymoma with lymphoid stroma (rare, indolent); Micronodular thymoma with lymphoid stroma (thymoma, thymic-epithelial)
- Tags: subtype-page; wave4; rare
- 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)

## Sections of this record

The page is a hub with ten sections in reading order; large sections have their own page. The same plan as JSON: https://onco.cc/api/v1/cancers/micronodular-thymoma/sections.json

- Overview (on the hub): The TL;DR, the family this cancer belongs to, the organ, who gets it and what the state of the art is. https://onco.cc/cancers/micronodular-thymoma/#overview
- What it is (on the hub): Anatomy, the subtypes and how they differ, how it is staged, and where advanced disease spreads. https://onco.cc/cancers/micronodular-thymoma/#what-it-is [3 subtypes]
- Finding it (on the hub): How it shows itself, how it is confirmed, what screening exists, and the biomarkers clinicians test for. https://onco.cc/cancers/micronodular-thymoma/#finding-it [4 biomarkers]
- Treating it (on the hub): The standard of care by setting, the medicines, surgery and radiotherapy named in it, and the regimens behind them. https://onco.cc/cancers/micronodular-thymoma/#treating-it [1 setting]
- Evidence (on the hub): Trials recruiting now, the landmark trials, the key papers and what they mean, the latest literature, and the milestones year by year. https://onco.cc/cancers/micronodular-thymoma/#evidence
- The science (on the hub): The molecular landscape: the targets and how often each appears, the pathways, the mechanics stages and the preclinical models. https://onco.cc/cancers/micronodular-thymoma/#science
- Where you are (own page): Cases by country, the UK and NHS pathway and other country lenses, and the expert centres with trials on record. https://onco.cc/cancers/micronodular-thymoma/where-you-are/
- Living with it (on the hub): The decisions you may face, the aids that walk through them, the warnings on record, the first sixty days and the questions to ask. https://onco.cc/cancers/micronodular-thymoma/#living-with-it [7 questions]
- What is coming (own page): Everything in development, the open problems and what is being done about them, the roadmaps, and what changed on this record. https://onco.cc/cancers/micronodular-thymoma/coming/
- Data (own page): Every connected record, the notes, the JSON, Markdown and RDF twins, and where the record came from and when it was checked. https://onco.cc/cancers/micronodular-thymoma/data/

## Standard of care

- All cases: Complete resection; associated lymphoma treated on the MALT lymphoma page; no adjuvant therapy. ([Thymoma (WHO types A, AB, B1, B2 and B3)](https://onco.cc/cancers/thymoma/), [Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma)](https://onco.cc/cancers/malt-lymphoma/))

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Thymoma
- NCI PDQ: thymoma and thymic carcinoma treatment: https://www.cancer.gov/types/thymus-cancer/thymoma-thymic-carcinoma
- Journal of Pathology 2005: micronodular thymoma, abnormal chemokine expression and lymphoma development: https://doi.org/10.1002/path.1808
- Histopathology 2015: micronodular thymoma with lymphoid stroma, Langerhans and dendritic cells in six patients: https://doi.org/10.1111/his.12428

## Connected records

- cancers: [Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma)](https://onco.cc/cancers/malt-lymphoma/), [Thymoma (WHO types A, AB, B1, B2 and B3)](https://onco.cc/cancers/thymoma/), [Thymoma and thymic carcinoma](https://onco.cc/cancers/thymic-epithelial/), [Type A and type AB thymoma](https://onco.cc/cancers/thymoma-type-a-ab/), [Type B1 and type B2 thymoma](https://onco.cc/cancers/thymoma-type-b1-b2/)

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JSON: https://onco.cc/api/v1/entities/micronodular-thymoma.json