Delayed-onset maxillary sinus–cutaneous fistula of the lower eyelid following zygomatic implant removal: A case report

Zygomatic implants are an effective option for rehabilitating severely atrophic maxillae, but can occasionally cause complications involving the maxillary sinus and surrounding soft tissues. We report a rare case of a delayed cutaneous fistula that developed 1 year after zygomatic implant removal. A 62-year-old man with progressive tooth loss due to familial aggressive periodontitis underwent zygomatic implant placement, which failed because of sinusitis and was subsequently removed. One year later, he presented with a mass at the lateral lower eyelid. Computed tomography demonstrated a linear bone defect along the previous implant tract and a bony opening directly beneath the mass, which was continuous with the maxillary sinus. Indigo carmine fistulography confirmed communication between the cutaneous site and the nasopharynx through the sinus. Histopathological examination revealed granulomatous inflammation without malignancy. Although debridement and curettage achieved temporary improvement, recurrence occurred several weeks later. Persistent sinus inflammation draining through a residual bony defect was considered the cause of the delayed cutaneous fistula. Clinicians should be aware that, even after zygomatic implant removal, chronic sinus infection may lead to cutaneous fistula formation, underscoring the importance of careful differential diagnosis and long-term follow-up in patients presenting with lower eyelid masses.