1059 - Sonographic Diagnosis of a Kaposiform Hemangioendothelioma Surrounding the Brachial Plexus in a 10-year-old: A Case Report

Case Diagnosis: Kaposiform Hemangioendothelioma surrounding brachial plexus.

Case Description: A 10-year-old girl with Henoch-Schonlein purpura presented with a 6-month history of pain in the left anterolateral elbow, predominantly at night. She had weakness of the left bicep and shoulder girdle, discoloration of overlying skin, and tenderness over the left brachial plexus. On examination she had hemihypertrophy of the left upper extremity, 4/5 strength in the left shoulder abductors and elbow flexors, and diminished sensation to light touch along the lateral left arm. Electrodiagnostic (EDX) testing was normal except for a low amplitude of her LABC nerve conduction study. Neuromuscular ultrasound (NMUS) showed an intense hypoechogenicity of the peri-plexus tissue which was suspicious for neoplasm. Based on the NMUS results, the patient was taken to surgery urgently for exploration. A biopsy was performed which suggested Kaposiform Hemangioendothelioma (KHE). After starting the patient on Sirolimus her pain and weakness improved. Shoulder and arm function have remained stable since.

Discussions: Unilateral, focal neuropathies arise from trauma, compression in fibro-osseous tunnels, and compression by masses such as tumors, as in this case. NMUS imaging is a powerful tool to distinguish between these possibilities while minimizing psychological and physical distress in the diagnostic process, particularly in pediatric populations.

Conclusions: EDX diagnostic tools are often poorly tolerated in the pediatric population and do not provide visual confirmation of the etiology of nerve pathology. In this case, NMUS was crucial in identifying a neoplastic etiology of the patient’s symptoms and facilitating timely diagnosis. Routine utilization of NMUS for focal disorders in the pediatric population allows for the timely identification and treatment of unusual etiologies, both improving diagnostic accuracy and the overall patient experience.