OH!  I"m so sorry! 

Did you vet suggest an ultrasound of Spencer's internal organs by chance?  I'm not trying to scare you but it's something I would do based on experience I had.  It may be totally different  and I hope it is but I would want to ensure the vital organs are okay.

 Maybe someone will come here that knows. 

So we all know what a hemangioma is - this is from the Vet Merck Manual:

Hemangiomas of the skin and soft tissues are benign
proliferations that closely resemble blood vessels. Whether these are neoplasms,
hamartomas, or vascular malformations remains undefined, and no clear criteria
exist that allow for their separation. They are most commonly identified in
dogs, occasionally in cats and horses, and rarely in cattle and pigs; they are
an exceptional finding in other domestic animals. In dogs, they are tumors of
adult dogs and most commonly develop on the trunk and extremities. Many canine
breeds (including Gordon Setters; Boxers; and Airedale, Scottish, and Kerry Blue
Terriers) are considered to be at risk. Cats most frequently develop hemangiomas
when they are adults. Lesions are most common on the head, extremities, and
abdomen. In horses, they are most common on the distal extremities of young
(<1 yr old) animals. In cattle, they may be seen as congenital lesions or in
older animals. Dairy cattle are predisposed to developing disseminated
hemangiomas (angiomatosis) in the skin and internal organs. In pigs, these
lesions generally develop in the scrotal or perineal skin of Yorkshire,
Berkshire, and less commonly Chester White boars. In the first 2 breeds, the
disease is believed to be genetically transmitted. Hemangiomas are single to
multiple, circumscribed, often compressible, red to black nodules. The lining
epidermis may be unaffected or ulcerated or papillated. Small, superficial
hemangiomas that often appear as a “blood blister” are known as angiokeratomas.
When erythrocytes are sparse or absent within vascular lumens, the term
lymphangioma is applied. Hemangiomas are benign, but their tendency to ulcerate
and grow quite large, along with the importance of confirming the diagnosis to
make a prognosis, indicate removal. Excision is the treatment of choice;
however, in large animals in which the lesions may be large and involve the
distal extremities, this may be difficult. In these cases, cryosurgery or
radiation therapy may be necessary. Except in dairy cattle with angiomatosis,
development of additional tumors at new sites after complete excision is
uncommon.

I'm sorry for sounding so dreadful!  I really didn't mean to sound like it was gloom and doom!   I was running out the door and should have waiting to post.

I absolutely don't know what I'm talking about.   I just worry about hemangiosarcoma which is tumors on the organs.  That is why I was wondering if your vet suggested an ultrasound.

I'm sorry for sounding dire!  I shouldn't have rushed!