I've had similar friendships. The person acts as if the two of you have been in constant touch for a lifetime and that it's perfectly normal to pick up the phone or send an email without any explanation or introduction of any kind as to why they have been basically ignoring you for the last six months or, oh maybe, 10 years. They commence dumping all their news, woes, tragedies, celebrations, and accomplishments on you without one word of inquiry about what's been going on in your own life, and then they're gone again. For another six months to 10 years.
Maybe they needed to vent. Okay, fine. There are many different types of friends, and, as long as they are nurturing and positive, there's room for them all: the talker, the listener, the comedian, the thinker, the mentor, the volunteer buddy, the exercise buddy, the work buddy, the best friend, the casual acquaintance. I have no problem with that. What I have a problem with is a lack of consistency and give and take. Don't just drop back into my life when it suits you if you aren't planning on committing to a full-on friendship.
Friendship is a commitment, whether that friend is across the hall or across the world. It means you commit to meeting three times a week to work out together; visiting regularly in person, on the phone, or via messaging; or inviting each other to events periodically. Commitment. It's not a one-sided, drop in-drop out relationship.
So, what should you do if you are faced with this situation? Well, if you still like the person and remember their friendship fondly, you could just deal with it. Call, chat a bit, and then let it go until the next time they pop back into your life. But if you have outgrown this particular person or they annoy you and you're just not interested in continuing the "friendship," you need to be honest. Let the person know how you feel about these surprise calls and one-sided conversations. Maybe they don't realize there's anything wrong with what they're doing. Or maybe they will fly off the handle about it, thinking you are an ungrateful jerk. Either way, you'll have cleared the air and will know where each other stands.
Do you have a friend who drops in out of the blue periodically? How do you handle it? Are you comfortable with it or is it a friendship that's been limping along for years that you would like to end? Think about what impact your actions would have on your life and that of your friend.