Spontaneous Isolated Superior Mesenteric Artery Dissection Presenting as Chronic Postprandial Abdominal Pain: Conservative Management of a Yun Type IIb Case.

Spontaneous isolated superior mesenteric artery dissection (SISMAD) is an uncommon but increasingly recognized vascular cause of abdominal pain due to the widespread use of advanced imaging. Its clinical presentation is variable, ranging from incidental findings to acute or chronic abdominal pain, and optimal management remains individualized based on clinical stability and radiologic features. We report the case of a 52-year-old male who presented with a six-month history of intermittent postprandial epigastric pain. Initial clinical and laboratory evaluations were unremarkable. Contrast-enhanced computed tomography aortography revealed a focal fusiform dilatation of the proximal superior mesenteric artery with a distinct intimal flap, resulting in separation into true and false lumens. The false lumen demonstrated partial thrombosis, while the true lumen appeared moderately narrowed, with an estimated luminal compromise of approximately 40-50% relative to the overall vessel diameter, but remained patent with preserved distal perfusion. There was no evidence of bowel ischemia or arterial rupture. Based on these findings, the diagnosis of isolated spontaneous superior mesenteric artery dissection, consistent with Yun type IIb morphology, was established. Given the patient's hemodynamic stability, absence of ischemic complications, and preserved mesenteric perfusion, a conservative management approach was adopted. Treatment included antiplatelet therapy, beta-blockade, statin therapy, and dietary modification. The patient demonstrated progressive symptomatic improvement and remained clinically stable at the six-month clinical follow-up without recurrent symptoms or clinical evidence of bowel ischemia. Follow-up imaging was not performed; therefore, radiologic disease progression or vascular remodeling could not be objectively assessed. This case highlights the importance of considering SISMAD in patients presenting with chronic postprandial abdominal pain, even in the absence of traditional vascular risk factors. Early use of computed tomography angiography is critical for accurate diagnosis and risk stratification. In carefully selected patients without bowel ischemia, conservative management can be safe and effective, provided that close clinical monitoring and follow-up are ensured.