A 65-year-old male presents with a history of difficult
climbing stairs and combing his hair of a few months duration. He has no major
medical problems, has not been on any medication. He smokes 20 cigarettes a
day. He has recently retired, he was a taxi driver.
On examination he is found to have no wasting, normal
tone, weakness of the muscles of his shoulder and pelvic girdle reflexes are
Chest x-ray reveals a shadow in his right lower zone
In this patient what is the likely diagnosis?