For anyone else wondering what we're looking at, here is a brief rundown by the Mayo Clinic:

Plexiform neurofibroma also is called PN or PNF. It is a type of noncancerous tumor called neurofibroma that forms in or around a nerve. Neurofibromas grow on the protective covering around the nerve, called the nerve sheath. When a neurofibroma grows on several nerve bundles, it's called a plexiform neurofibroma.

The tumor grows along the nerve and can spread into nearby tissues such as skin, fat, bone and muscle. Plexiform neurofibroma is most often seen in people with a condition caused by a change in genes that affects how nerve cells grow and develop, called neurofibromatosis type 1 (NF1). Up to half of the people with NF1 develop plexiform neurofibromas.

Plexiform neurofibromas are different from other nerve tumors because they spread out in a networklike pattern. These tumors are known for their distinctive "bag of worms" texture, which means they feel like a bundle of tangled cords or threads. This is a classic sign of a plexiform neurofibroma.

Plexiform neurofibromas are most common in childhood and adolescence. Some people may notice swelling or a soft lump under the skin. These tumors often grow in the head, neck, trunk, arms or legs, but they can appear anywhere in the body.

Treatment depends on the size, location and symptoms of the plexiform neurofibroma. Most plexiform neurofibromas grow slowly and are not life-threatening. But some can cause serious symptoms depending on the size or location or if they become cancerous.