Gingival enlargement is seen in all of the following EXCEPT:

Gingival enlargement (overgrowth) is associated with: phenytoin (drug-induced gingival hyperplasia), calcium channel blockers (nifedipine), cyclosporine, scurvy (Vitamin C deficiency causes abnormal collagen formation and gingival swelling), sarcoidosis (granulomatous disease can cause gingival swelling), leukemia, Crohn's disease, and pregnancy. Herpetic gingivostomatitis (primary HSV-1 infection) causes painful vesicles and ulcers on the gingiva and oral mucosa, but the primary finding is ulceration and necrosis — not gingival enlargement (overgrowth/hyperplasia). Therefore, gingivostomatitis is the EXCEPTION.