A case of primary frontal sinus aspergilloma in a 79 year old non-immunocompromised woman, who presented with a right sided pyocele expanding into the orbit, is presented. The low susceptibility of the frontal sinus is probably related to the brachycephalic shape of the human skull which locates this sinus far anterosuperiorly to the nasal cavity. In human frontal sinus aspergillosis nasal symptoms are absent; the clinical manifestation of this rare disease is initiated by complications, especially orbital or intracranial invasion. Sinus opacity may raise early suspicion. Treatment consists of surgical debridement and re-aeration. Diagnosis is established by histological analysis of intraluminal contents.