Biomedical subjects
Publications and source records attributed to D P Lau.
This paper focuses on the spectrum of sphenoid sinus lesions that may be seen radiologically and the mapping of disease extent. Imaging plays a central role in the assessment of sphenoid sinus disease. Although primary sphenoid sinus disease is uncommon, this sinus is nevertheless affected secondarily by a variety of pathological processes.
Isolated sphenoethmoid recess (SER) polyps are rare. They usually arise from the sphenoid sinus. We report six patients with SER polyps as the only abnormal clinical finding at initial presentation. All cases were investigated with outpatient biopsy and computed tomography (CT) or magnetic resonance (MR) imaging. Pre-operative histology revealed three cases of inflammatory disease, two cases with inverted papilloma, and one case of an ectopic pituitary adenoma arising from the sphenoid sinus. One of the inflammatory polyps arose directly from the mucosa around the sphenoid ostium. The other five cases involved the sphenoid sinus. Except for the ectopic pituitary adenoma all the polyps were managed by transnasal endoscopic surgery. We emphasize that isolated SER polyps may signify existing sphenoid pathology and a pre-operative biopsy is valuable for planning surgery.
A case of chrondrosarcoma of the petrous temporal bone is presented. Chondrosarcomas rarely occur intracranially and typically present apex mass. The dilemmas faced in the diagnosis and treatment of petrous apex chondrosarcomas are discussed. This case also gives interesting insight into the natural history of this tumour.
We describe two cases of sphenoid sinus mucocoele. Both presented with isolated oculomotor nerve palsy. Mucocoeles involving only the sphenoid sinus are uncommon. They are probably under-diagnosed as they may be asymptomatic or cause non-specific symptoms. Nasal symptoms occur infrequently but the close relationship of the sphenoid sinus to the orbital apex means that ocular symptoms including cranial nerve palsies are a common presenting feature. Involvement of the third cranial nerve in isolation is rare but has important neurosurgical implications which must be excluded before this symptom is attributed to the sphenoid sinus.
Epithelial-myoepithelial carcinoma (EMC) accounts for approximately one per cent of salivary gland tumours. This tumour is gaining wider recognition following inclusion into the WHO histological classification of salivary gland tumours in 1990. Salivary gland tumours characteristically present with an enlarging mass. We describe an unusual presentation of a salivary gland tumour with stenosis of the external ear canal in the absence of a palpable mass. EMC usually arises from the salivary glands but isolated cases have been described arising primarily from the paranasal sinuses, trachea and lacrimal gland. The management of this tumour is still evolving with surgical excision being the main-stay of treatment. The efficacy of radiotherapy has not yet been established but high local recurrence rates despite apparently adequate excision and the possibility of a multicentric origin of the tumour may herald an increasing role for radiotherapy in the future. We stress the importance of awareness of adjacent structures when considering the cause of cartilaginous canal stenosis.
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Lesions of the orbital apex often present a diagnostic dilemma. Clinical assessment and imaging studies are helpful but a tissue biopsy is often required. The morbidity associated with transcranial approaches to the orbital apex may outweigh the benefits of obtaining a biopsy by these routes. Fine needle aspiration cytology of orbital apex lesions can be performed but there are disadvantages with this method. We describe a transnasal endoscopic technique to biopsy the orbital apex. The technique was used successfully to obtain a tissue diagnosis in six patients with orbital apex lesions. This enabled commencement of definitive treatment. There were no significant complications. The transnasal approach to the orbital apex using the endoscopes is reliable. Endoscopes provide excellent illumination, magnification, and a panoramic view of the operative field.