When an abnormal conglomeration of blood vessels within internal organs or the skin occurs—malformations arising from vessels that separate the arterial and venous systems of the body—the lesions that develop are known as cavernous hemangiomas. These malformations can cause hemorrhages if left untreated, and can be life threatening if they are present in a vital internal organ.

Physicians are unsure as to what causes cavernous malformations, but it is known that at least one-third are present at the time of birth, while the remaining two-thirds develop in the first months of life. They are typically located in the various layers of the skin, but can also be found within the internal organs.

When they occur in the skin cavernous malformations appear as either a raised, red, lumpy area of flesh or, if they’re under the skin, as a swelling that is bluish in color. And when they occur in an internal organ, they would present as a malfunction or failure of that organ.

The lesions are easy to see and therefore easy to diagnosis when they appear on or under the skin, but when they’re located deep in the body a CT scan or MRI is necessary for diagnosis. Once found, the treatment for the condition will depend on the location of the lesion as well as its size and whether it’s affecting the normal functions of the body.

If the abnormality is small and not impacting other body systems, physicians will likely leave it alone and continue to monitor the condition. If however it’s large and easy to access, it can often be removed surgically. When multiple hemangiomas exist or if they’re inside an internal organ such as the brain, surgery is necessary and very difficult to perform; a physician may opt for focused gamma radiation therapy instead, which has shown to be effective at least for a short-term prognosis.