Is breast enlargement a symptom of citalopram?

Rare, but possible: It is extremely rare, but some antidepressants have been associated with elevations in a hormone, prolactin. This can cause the problem asked. This problem is more common with antipsychotic medications.

Not common : This is a relatively common antidepressant and I am not aware of this as a common side effect unless associated with weight gain which is more common.