Parotid gland follicular lymphoma lacking both cytoplasmic and surface light chains: a rare case

Area of Science:

• Hematology
• Oncology
• Immunology

Background:

• Immunoglobulin light chain (LC) restriction is a standard diagnostic marker for B-cell non-Hodgkin lymphoma (B-NHL) using flow cytometric immunophenotyping (FCI).
• A small subset of mature B-NHLs are known to lack surface LC, but deficiency in both cytoplasmic and surface LCs is exceedingly rare.

Observation:

• This report details a case of primary parotid gland follicular lymphoma in a 63-year-old male patient.
• The lymphoma cells in this case exhibited a deficiency of both cytoplasmic and surface LCs.

Findings:

• A more sensitive FCI method, utilizing a combination of monoclonal and polyclonal anti-LC antibodies, was employed.
• This advanced technique confirmed the absence of LCs in the lymphoma cells, a finding previously reported in only three B-NHL cases.

Implications:

• The absence of LCs presents a significant diagnostic pitfall for initial B-NHL diagnosis.
• This immunophenotypic aberrancy also poses challenges for the accurate detection of minimal residual disease.
• Awareness of this rare finding is crucial for accurate diagnosis and patient management in hematologic malignancies.