NF is a difficult disease. There are 2 distinct families of NF, type 1 and type 2. I'm more fluent in type 2 because I have that particular disease. NF2 causes lesions on the CNS and PNS - many tumors can be excised easily if caught early, but as they grow and embed themselves around nerves and into other organs, removal can cause more neurological damage than leaving the tumor where it is. Until the last decade or so, there wasnt much in the way of medical intervention for NF. These lesions are slow growing, so theyre often not caught until they are rather substantial in size. I'm not sure if the man had type 1 or 2, but I'm assuming since the tumor was so incredibly large, that it had been growing for many, many years. When the doctors first saw the tumor, it may have been so intertwined on nerves and other organs, they possibly couldnt remove it.
Now that doctors and neurologists are more aware of NF (Nf is very rare and most doctors wont go near it), there are more areas of study and specialists who know how to manage the disease. A specialty team of doctors, routine full body MRIs, audiograms, etc. is an absolute must when treating this disease to ensure that cases like this are avoided.