The cause of follicular lymphoma (FL) in situ (FLIS) is unknown. It is believed to be a precursor lesion of FL, however, the exact role of FLIS in the development of lymphoma is not yet known.
FLIS is diagnosed mainly by histopathological examination of a biopsy specimen. It is important to distinguish FLIS from other forms of lymphoma as it has a different prognosis and management.
Differential diagnosis of FLIS includes other low-grade B-cell lymphomas, such as small lymphocytic lymphoma, marginal zone lymphoma, and mantle cell lymphoma. It is also important to rule out other benign processes that can mimic FLIS, such as follicular hyperplasia.
Treatment for FLIS is generally watchful waiting. It is important to monitor patients for potential progression to FL, as well as for other complications.
The prognosis for FLIS is generally good, as it rarely progresses to FL. However, patients should be monitored regularly for potential progression and other complications.