Richter transformation occurs when chronic lymphocytic leukemia transforms into aggressive lymphoma, most commonly diffuse large B-cell lymphoma (DLBCL), in approximately 5-10% of CLL patients. While typically presenting as rapidly enlarging lymph nodes, extranodal involvement can occur. Splenic transformation is uncommon, and spontaneous splenic hemorrhage represents an extremely rare, life-threatening complication requiring immediate recognition and intervention.

A 71-year-old female with established CLL presented with progressive abdominal pain, fatigue, and anorexia. She had previously received CLL-directed therapy with initial lymph node regression during follow-up. Physical examination revealed poor general condition, left upper quadrant tenderness with fullness, and minimal peripheral edema. No palpable lymphadenopathy was detected.

Laboratory evaluation demonstrated cytopenias: hemoglobin 9.1 g/dL, leukocytosis 13.6 × 10³/µL (lymphocyte-predominant), and thrombocytopenia 83 × 10³/µL. Coagulopathy was evident with prolonged PT (17.2 seconds) and elevated INR (1.46). Additional findings included suppressed TSH (0.07 mIU/L) suggesting hyperthyroidism and elevated ferritin (402 ng/mL).

PET-CT performed on May 22, 2025, showed regression of previously enlarged cervical, axillary, iliac, and inguinal lymph nodes, indicating prior treatment response. However, a large hypermetabolic splenic lesion measuring 103 × 60 × 61 mm with SUVmax 32.82 was identified, with evidence of lateral capsular invasion. No bone marrow or hepatic FDG uptake was observed.

Subsequent CT imaging on July 24, 2025, revealed alarming findings: intraparenchymal and subcapsular splenic hematoma with perihepatic, perisplenic, and pelvic free fluid consistent with hemoperitoneum. Additional incidental findings included a 17 mm right thyroid nodule and minimal left pleural effusion.

Splenic tru-cut biopsy performed on July 17, 2025, confirmed diffuse large B-cell lymphoma with germinal center phenotype. Immunohistochemistry showed CD20(+), Bcl-2(+), Bcl-6(+), MUM-1(+) with high proliferation index (Ki-67: 80%) and elevated c-Myc expression (60%). CD10 and CD5 were negative.

The clinical constellation of findings confirmed Richter transformation with splenic DLBCL complicated by spontaneous splenic hemorrhage and hemoperitoneum, representing a medical emergency.

This case demonstrates an exceptionally rare presentation of Richter transformation. While most Richter transformations present with rapidly enlarging lymph nodes, isolated splenic involvement is uncommon. The extremely high SUVmax (32.82) indicated aggressive disease with high metabolic activity, consistent with high-grade DLBCL.

The development of spontaneous splenic hematoma likely resulted from tumor infiltration weakening the splenic capsule and parenchyma, combined with underlying thrombocytopenia and coagulopathy. The resulting hemoperitoneum represents a life-threatening complication requiring urgent intervention.

The coagulopathy and cytopenias observed may reflect both disease progression and splenic sequestration. The concurrent thyroid abnormalities warrant investigation for secondary malignancies or treatment-related complications.

Management challenges include balancing the need for immediate treatment of aggressive lymphoma against the risk of exacerbating bleeding complications. Careful coordination between hematology, surgery, and radiology teams is essential for optimal outcomes.

Richter transformation can present with rare but life-threatening complications including spontaneous splenic hemorrhage. High clinical suspicion, urgent imaging, and multidisciplinary management are crucial for patients with CLL developing new abdominal symptoms. This case underscores the importance of recognizing atypical presentations of Richter transformation to ensure prompt diagnosis and appropriate intervention.