Lymphangiomatosis: a rare entity presenting with involvement of the sacral plexus.

Lymphangiomatosis is an uncommon disease process characterized by multisystem lymphatic malformations that can involve numerous body systems, including organs, muscles, soft tissues, and bones. Involvement of the nervous system is rare and has even been previously described as a site of sparing. We present a case of a 24-year-old female with known lymphangiomatosis, presenting with acute onset of lower extremity paresthesias, weakness, and new urinary retention. MRI of the pelvis revealed lymphangiomatosis of the sacral plexus, which has not been previously reported. We will review the clinical and imaging manifestations of lymphangiomatosis and provide a differential diagnosis for masses of the lumbosacral plexus. Although lower extremity pain and weakness encountered in the emergency department or outpatient setting is most frequently caused by lumbar spine pathology, occasionally, abnormalities of the lumbosacral plexus may prove to be the cause. While peripheral nerve sheath tumors lead the differential diagnosis of tumor or tumor-like entities involving the lumbosacral plexus, lymphangiomatosis is a rare differential consideration.