B symptoms are a set of symptoms, namely fever, night sweats, and unintentional weight loss, that can be associated with both Hodgkin lymphoma and non-Hodgkin lymphoma. These symptoms are not specific to lymphomas, especially each one considered individually, and even as a trio they are not pathognomonic for lymphomas, but the presence of the trio is sensitive enough for lymphomas to warrant diagnostic investigation and differential diagnosis. The presence or absence of B symptoms has prognostic significance in lymphomas and is reflected in their staging.
B symptoms are so called because Ann Arbor staging of lymphomas includes both a number (I–IV) and a letter (A or B).[1] "A" indicates the absence of systemic symptoms, while "B" indicates their presence.
B symptoms include:
The presence of B symptoms is a marker for more advanced disease with systemic, rather than merely local, involvement. B symptoms are a clear negative prognostic factor in Hodgkin lymphoma.[2] The relevance of B symptoms in non-Hodgkin lymphoma is less clear, although B symptoms tend to correlate with disease that is either more widespread or of a higher histologic grade.[3]
It has been suggested that, in Hodgkin lymphoma, fever and weight loss are much more prognostically significant than night sweats. In one series of patients with early-stage Hodgkin disease, the presence or absence of night sweats had no impact on cure rates and outcome. However, fever and weight loss had a pronounced negative impact on cure and survival rates, regardless of treatment modality.[4]