Pediatric acute dacryocystitis typically develops due to persistence of Hasner's membrane. Pediatric paranasal mucoceles are rare entities. In contrast, chronic dacryocystitis in cases of congenital dacryostenosis is one of the most frequent pediatric ophthalmologic issues.The case report of a 10-year-old girl suffering acute dacryocystitis is presented.The area around the left lacrimal sac showed a painful swelling with edema and hyperemia. Systemic and local antibiotic therapy resulted in only slight improvement. Dacryoendoscopy detected acute dacryocystitis with significant stenosis of the nasolacrimal duct. The nasolacrimal duct was widened dacryoendoscopically and autostable bicanalicular nasolacrimal intubation was performed. Nevertheless, the lacrimal ducts were blocked subtotally and a widening of the ethmoid on the left side was shown by rhinoscopy. Magnetic resonance imaging confirmed a frontoethmoidal mucocele which was treated by marsupialization. During the 24-month follow-up there was no recurrence of acute dacryocystitis. There were no signs of sinusitis.Paranasal mucoceles, e. g., ethmoidal mucoceles, can compress the lacrimal pathways and cause acute lacrimal inflammation in childhood. Paranasal mucoceles should thus be excluded in cases of unclear masses in the lacrimal region.