Craniofacial fibrous dysplasia mimicking sinunasal mucocele: Case report

Abstract

Background: Fibrous Dysplasia is a congenital, non-inherited, benign intra-medullary bone lesion in which the normal bone marrow is replaced by abnormal fibro-osseous tissue. It can manifest in axial and extra -axial skeleton and tissues. The wide range of clinical manifestations from skeletal changes to soft tissues swellings and skin discoloration makes it a disease of note in the clinical settings. Some of its complications include malignant transformation, gastrointestinal reflux to cardiac involvement with arrhythmias and even sudden death. Until recently with advent of modern imaging modalities, it was a disease of diagnostic debacle as it was often misdiagnosed .This is a case report of a 17 year old male who was misdiagnosed as sinunasal mucocele until histology proved it to be fibrous dysplasia. Objective: The objective of the report is to draw attention to the diagnostic challenge posed at CT imaging. Methods: This case report was carried out at University College Hospital Ibadan. Results: Showed right sided facial swelling measuring about 15x10cm. The mass was firm to hard in consistency, non-tender and not attached to the overlying skin. There was no loss of sensation in the skin over it. The right eye was displaced superiorly and laterally. A nasal aspect of the mass was seen to occupy the whole of the ipsilateral nasal cavity which it occluded deviating the nasal septum to the left and narrowing the left nasal cavity. It was fleshy and showed contact bleeding. The attending ENT Surgeons made a working diagnosis of right sinunasal tumour with possible malignant transformation. The radiographs of the sinuses showed expansile sclerotic lesion involving the nasal bones, the right maxillary bone, right ethmoidal and maxillary sinuses. The inferior aspect of the right frontal sinus was also affected. A cranial computed tomography (CT) scan (Fig 2-4) showed a multi-loculated hypodense mass with mildly enhancing septations (HU16) within the right frontal, ethmoidal, sphenoidal and maxillary sinuses. There was associated expansion of the affected sinuses with thinning of their cortices. No evidence of aggressive bony destruction was seen. The radiologists made a diagnosis of benign sinunasal tumour most likely mucocele. After right maxillectomy, histology proved the lesion to be fibrous dysplasia. This report goes further to support the need for application of more imaging modalities especially the modern and higher slices CT scanner, higher Tesla(2T )MRI , PET and fusion CT/PET scanners in arriving at radiological diagnosis that will be more compatible with the pathological condition of the patients as against what was in place at the time of this case report .Radiologists are also encouraged to have a high index of suspicion for the disease and to explore the possibilities of the differentials in order not to miss the diagnosis of FD