Atraumatic Splenic Rupture: A Case Report.

Atraumatic splenic rupture (ASR) is a rare but potentially fatal emergency, accounting for less than 0.5% of all splenic ruptures. Its nonspecific presentation often complicates diagnosis and management. True idiopathic ASR, occurring without an underlying splenic disease, is extremely rare. We report the case of a 61-year-old woman with diffuse large B-cell lymphoma in complete metabolic remission who developed sudden, severe epigastric and left upper quadrant pain 7 days after receiving high-dose methotrexate for central nervous system prophylaxis. There was no evidence of splenic involvement by lymphoma or other predisposing factors. The patient rapidly progressed to hemorrhagic shock. Imaging identified a large subcapsular splenic hematoma with active bleeding, necessitating emergent splenectomy. Following surgery, she achieved hemodynamic stabilization and recovered without postoperative complications, remaining disease-free at the six-month follow-up. Histopathological examination confirmed preserved splenic architecture without malignancy, vascular pathology, or amyloid deposition. This case highlights the risk of diagnostic anchoring bias in patients with a history of hematologic malignancy, as ASR may be incorrectly attributed to disease recurrence. In the absence of splenic involvement or identifiable risk factors, histopathological confirmation was essential to establish the diagnosis of true idiopathic ASR and to guide appropriate management.