Extensive multifocal extranodal diffuse large B-cell lymphoma involving parotid, breast, gastrointestinal tract, and...

Diffuse large B-cell lymphoma (DLBCL) is the most common type of non-Hodgkin lymphoma, with extranodal involvement in up to 40% of cases. However, simultaneous involvement of multiple extranodal sites without dominant nodal disease remains very rare and diagnostically challenging.

We report a case of a 61-year-old female with a history of hypertension and recurrent anemia, who presented with progressive swelling in the left breast and parotid area, and systemic symptoms. Evaluation with imaging and biopsy confirmed multifocal extranodal DLBCL involving the bilateral parotid glands, left breast, stomach, and thoracic spine. Immunohistochemistry showed CD20 and BCL2 positivity and a high Ki-67 index (70%-80%), which was suggestive of an aggressive non-germinal center B-cell phenotype. The patient was given R-CHOP chemotherapy and intrathecal methotrexate with a favorable early response.

This case illustrates the difficulty in diagnosing multifocal extranodal lymphoma in the context of the absence of dominant nodal disease. Extranodal DLBCLs can mimic primary organ cancers and lead to misdiagnosis or delayed therapy. With the poor prognosis of widespread extranodal disease and potential molecular high-risk features, multidisciplinary management and diligent long-term surveillance are essential. Limited access to molecular analyses (e.g. MYC/BCL2/BCL6) in resource-limited settings remains a significant challenge.

Multifocal extranodal DLBCL with parotid gland, breast, gastrointestinal tract, and spine involvement is extremely rare and requires a very high index of suspicion. Image-guided biopsy and immunophenotyping at an early stage are crucial to avoid misdiagnosis and guide appropriate therapy. Individualized and risk-adapted approaches are crucial in maximizing the outcome in such aggressive and rare presentations.