I am so sorry to hear about your father and I can relate: my 75 yr old Dad was diagnosed with same thing Aug. 2007; also after misdiagnosis of skin cancer (which he did also have!) It is rare, for sure. Not much for data, or info. His lesion was large and growly quickly. It started to ulcerate & bleed, It was a mess.
He never had surgery due to other issues (diabetes & blood clots). He was always told no matter what, it always comes back. He had several types of chemo over a 10 mos period. Our oncologist (my Mom and I also were dealing with cancers at the same time-but that's another story) was in e-mail touch with the Head of Sarcomas at Dana-Farber, who was suggesting different, newer chemo ideas. It got better, then worse again. He also then had radiation for 7 wks starting Aug. 2008. He tolerated it very very well-and it bought time, but right afterward, it started growing again.
He died Dec. 2008; after getting to his last option which would have been with Avastin-but due to his bloot clot situation would have been dicey. He was failing & weakened-blood counts so low, etc. and we all decided to get hospice and keep him home & comfortable. My mother had died of her cancer at home, with hospice, just 2 mos before him.
I think if he'd have had surgery in the beginning-IF his health would have allowed it-it may have helped alot. To get clean margins, they also would have had to remove the whole top of his scalp-sounded very ominous. Some of the Dr's he saw believed he should have no matter what! I sure hope that's the case with your Dad. We had him to the (MN) Mayo also-even they hadn't seen that many cases of this-especially so far advanced as my Dad's was.
I hope things go well,-how old is your Dad? It definitely hits older men, as a rule. It was never painful, thank goodness-more aggrevating with the bleeding and it looked like hell! We became experts in cleaning and dressing.
I don't mean to be negative here-just honest. I sure wished I could have communicated with someone in this same situation at the time-I was on this board briefly, looking for info & help, too. Feel free to reply to me-if I can help in any way. I am a Head & Neck, squamous cell carcinoma survivor-2 yrs & counting!!!!!! Best of everything to your Dad and family! Gayle