Diffuse Large B-Cell lymphoma Misdiagnosed as a Hematoma: Case Report.

Background: Diffuse large B-cell lymphoma (DLBCL), the most common subtype of non-Hodgkin's lymphoma, often presents diagnostic challenges due to its diverse clinical presentation. We present a case of DLBCL that was initially misdiagnosed as a hematoma, highlighting the importance of considering malignancy when faced with unresponsive soft tissue swelling. Methods: A 76-year-old man presented to the emergency department with right periorbital swelling and ecchymosis following a traumatic injury. Despite ongoing anticoagulant therapy (warfarin) for atrial fibrillation, the symptoms persisted. A CT scan of the facial bones revealed a large, irregular, homogeneous mass. Initially, the clinical history and radiologic findings suggested an extraconal hematoma. As a result, an incision and drainage procedure was performed, and the old blood was evacuated. However, the patient's symptoms continued to worsen. A follow-up CT scan showed enlargement of the lesion, prompting a surgical excisional biopsy. Results: Pathologic examination of the excised mass revealed a diffuse infiltrate of lymphocytes surrounding the tissue, confirming the diagnosis of diffuse large B-cell lymphoma (DLBCL). The patient was subsequently referred to hematology for further management. Conclusions: Although rare, DLBCL is associated with a challenging prognosis. This case highlights the diagnostic complexities that can arise, particularly when factors such as prior injury and anticoagulant therapy confound the clinical picture. The initial misclassification of the condition as a hematoma led to a delay in diagnosis and the subsequent initiation of treatment. Therefore, it is imperative to remain vigilant and consider malignancy as a potential underlying cause of unresponsive soft tissue swelling. Timely recognition and accurate diagnosis are paramount to improving patient outcomes in DLBCL, an aggressive lymphoma with a diverse clinical presentation.