Recent Diagnosis Histiocytic Sarcoma

Hi, my husband had just been diagnised with HS as I will call it. We are in the UK and wondering of any specislists (names etc) in this field and effective treatments you/loved ones have had or heard of. We are seeing heamatology for the first time in 2 days. Any questions we should ask? HS presented as a lump in thigh. 50 years old. Thank you.