It also displayed similar features to squamous cell carcinoma - a type of skin cancer, and "follow up" with the patient was advised.
However Mr B saw the diagnosis of keratoacanthoma, regarded it as "normal" and didn't pass it on to the man.
The Health and Disability Commission decision stated he also didn't read the advice to follow up and further biopsy wasn't needed.
He saved the report to the man's file and did not make a file note.
"The GP did not tell the man the results or provide any follow-up advice, despite the man having been told that he would be contacted again if follow-up was necessary," the commission found.
Later that year the man returned to the medical centre for wound review and suture removal by nurses, however the pathology was not discussed with the man.
It was the medical centre's policy that nursing staff did not discuss pathology with patients.
The man consulted staff at the medical centre for lesions on his ears, lip, left leg and hands.
The results of the biopsies in each case were given to the man at the time of suture removal. The man did not mention any recurrence of the scalp lesion at these appointments.
About a year later the man's scalp lesion reappeared and he decided to see a specialist where a biopsy was taken.
The new report came back positive for squamous cell carcinoma (SCC), and the man was advised that urgent surgery was required.
The Commissioner found the doctor failed to "take reasonable care and skill in reading the histology report and failed to provide the information contained in the histology report to the man".
The Heath and Disability Commissioner Mr Hill was "satisfied" the handling of laboratory results were adequate from the medical centre.
The doctor apologised to the man.
The Commissioner recommended that the medical centre audit patient records with abnormal test results to make sure patients have been informed of those results and follow-ups organised.
