An Unusual Sonographic Presentation of Pediatric Fibromuscular Dysplasia (FMD) Presenting as Possible Appendicitis

Sonography has become a common diagnostic tool for detecting appendicitis in children. It is driven by the need to limit radiation exposure and advances in high frequency transducer resolution. However, symptoms often remain nonspecific, particularly in young or nonverbal patients. When the appendix is not clearly visualized, sonographers should extend their evaluation to other areas of the abdomen. Most diagnostic differentials are either gastrointestinal (GI) or genitourinary (GU) related, although blunt abdominal trauma should be included. This patient was found to have a hemorrhagic left kidney, which led to a diagnosis of fibromuscular dysplasia (FMD). Fibromuscular dysplasia is an idiopathic, noninflammatory disease of the medium sized arteries in the body which causes stenosis, occlusion, dissection, tortuosity, and aneurysms to occur. It is a condition that is diagnosed via image findings. Most commonly, it is diagnosed in pediatric patients with renovascular hypertension that undergo renal artery Doppler evaluation.