From the Guidelines
Lymphoma can indeed present with a normal peripheral blood smear (PBS), as the disease often originates in lymphoid tissues and may not necessarily involve the peripheral blood [ 1 ]. In fact, many patients with lymphoma, particularly those with indolent subtypes such as follicular lymphoma, may have a normal complete blood count (CBC) and peripheral smear at diagnosis [ 1 ].
Key Points to Consider
- Notably, even in cases where lymphoma cells are present in the blood, they may not be detectable on a routine peripheral smear, highlighting the importance of additional diagnostic testing, such as flow cytometry or bone marrow biopsy, to establish a definitive diagnosis [ 1 ].
- The diagnosis of lymphoma should always be based on a surgical specimen/excisional lymph node biopsy, and a complete blood count, routine blood chemistry, and screening tests for HIV and hepatitis B and C are required [ 1 ].
- Bone marrow biopsy is usually included in the workup for all patients with non-Hodgkin's lymphoma (NHL), except those with certain subtypes, and is essential for staging and restaging [ 1 ].
- FDG-PET scan has been used for initial staging, restaging, and follow-up of patients with NHL, and is nearly universally positive at diagnosis in certain subtypes, such as Hodgkin lymphoma, DLBCL, and FL [ 1 ].
From the Research
Lymphoma Presentation
- Lymphoma can present with a variety of symptoms and laboratory findings, including abnormalities on peripheral blood smears (PBS) 2, 3, 4, 5.
- However, it is also possible for lymphoma to present with a normal PBS, as some cases may not have circulating lymphoma cells or may have a low level of involvement that is not detectable on a routine blood smear 3, 5.
Peripheral Blood Smear Findings
- The presence of atypical lymphoid cells or smudge cells on a PBS can suggest lymphoma, but these findings are not specific and can be seen in other conditions as well 4, 5.
- Flow cytometric immunophenotyping of peripheral blood can be helpful in diagnosing lymphoma, but it is not always possible to establish a definitive diagnosis based on PBS findings alone 2, 6, 4.
Diagnostic Challenges
- The diagnosis of lymphoma often requires a combination of clinical, laboratory, and histopathological findings, and a normal PBS does not rule out the possibility of lymphoma 3, 4, 5.
- Additional diagnostic tests, such as bone marrow biopsy, lymph node biopsy, and flow cytometry, may be necessary to establish a definitive diagnosis of lymphoma 2, 6, 4, 5.