Biopsy result waiting time

Hi 

I noticed a lump on my back, near shoulder blade, last November.

 I saw my GP who thought it was a lipoma but couldn't be certain so sent me for ultrasound.

Both the ultrasound and subsequent MRI scan were inconclusive and I was referred for a biopsy in February.

I heard nothing back for 4 weeks so phoned hospital and they said report was with doctor and I would hear soon.

Last week, I got letter from hospital inviting me to an outpatient appt at hospital on 6th May but otherwise letter said nothing.

Couple of questions - is it normal for letter to be so uninformative and if the biopsy had been positive is it normal to wait so long for news?