As Sutured Ghoul says
As Sutured Ghoul enters the battlefield, exile any number of creature cards from your graveyard.
Sutured Ghoul's power is equal to the total power of the exiled cards and its toughness is equal to their total toughness.
The text says the exiled cards, so does only count on cards that are exiled by himself, or does every exiled creature counts?
The oracle does not mention any reference to this:
22/09/2011 If any of the creature cards you exile has a characteristic-defining ability that defines its power and/or toughness, that ability will apply. For example, if Dungrove Elder is exiled this way, its power and toughness while it’s in exile are equal to the number of Forests you control, and Sutured Ghoul’s power and toughness will change as the number of Forests you control changes. If the characteristic-defining ability can’t be applied (for instance, it relies on a choice made as the card enters the battlefield), then use 0.
22/09/2011 In zones other than the battlefield, Sutured Ghoul’s power and toughness are each 0.
22/09/2011 You can’t have Sutured Ghoul exile itself, even if it’s entering the battlefield from your graveyard.