Mucous cyst of the sphenoid sinus A.G. Farman and I. Baker* Department of Primary Patient Care and 'Department of Growth and Special Care, School of Dentistry, University of Louisville, Louisville, Kentucky, USA
Received 24 January 1990 and in final form 19 April 1990 Sphenoid sinus mucous cysts are rare, benign, expansile masses, which can form mucoceles if the entire sinus is filled. Due to their close proximity to numerous important anatomical structures, they can cause a variety of different symptoms. The incidental finding of a sphenoid sinus mucous cyst during cephalometric radiology for orthodontic analysis is reported. Keywords: Mucocele; sphenoid sinus; radiography, dental
Oral and maxillofacial radiologists are generally familiar with the 'mucocele' of the maxillary sinus. This is frequently seen as an incidental finding on both periapical views of the maxillary posterior teeth and panoramic radiography as a dome-shaped lesion. It is usually asymptomatic and rarely further requires patient referral or treatment 1. As these lesions do not generally fill the whole maxillary sinus, they are perhaps better termed 'mucous cysts' or 'mucous extravasation phenomena' to conform with the accepted nomenclature in the medical radiology literature. The pathogenesis appears to be that of a mucoid collection beneath the lining epithelium of the sinus rather than a retention phenomenon within dilated ducts of mucous glands. If left untreated, they may resolvej. In comparison with 'mucoceles' of the maxillary sinus, those of the sphenoid sinus are uncommon. Sphenoethmoidal mucoceles are benign, expansile masses; however, they can also be locally destructive, and this fact has sometimes led to their being misdiagnosed as a malignant neoplasm/-". Furthermore, the sphenoid sinus is closely related to many important anatomical structures and their compression can lead to a variety of signs and symptoms. Such presentations include frontal or retro-orbital headache and visual abnormalities such as ocular field defects, o~hthalmo plegia, proptosis, and even sudden blindness ,6. Other features reported have been nasal obstruction, rhinorrhea, anosmia, dysfunction of the third through sixth cranial nerve supplies and various endocrine disorders including diabetes 7-9. Intracranial extension of the mucocele per se is extremely rare 10, J I . In view of the infrequency of occurrence of sphenoid sinus mucous cysts, the paucity of reports in the oral and maxillofacial radiology literature, and the potential serious consequences of such lesions if they are allowed to develop into mucoceles, a case is illustrated which was an incidental finding on cephalometric radiography in the course of orthodontic treatment.
IS-month period. A lateral cephalometric radiograph to evaluate both growth and progress of treatment, revealed a well defined, oval-shaped, radiopaque mass in the region of, or superimposed upon, the sphenoid sinus, its upper extension appearing 1.5 mm below the shadow of the sella turcica (Figure 1). Retrospective review of the initial cephalometric radiograph taken 15 months earlier showed a much smaller mass in the same site with its upper extension only 5 mm below the shadow of the sella turcica (Figure 2). Physical examination of the head and neck did not reveal any abnormality. The patient's medical and dental histories were non-contributory and the patient denied symptoms that could be attributed to the radiological findings. A submentovertex radiograph was taken to further localize the radiopaque mass (Figure 3). This confirmed it was in the sphenoid sinus and extended across its whole floor. Linear tomography in the mid-sagittal plane (Figure 4) clearly demonstrated the lesion to be dome shaped and well demarcated without a cortical outline and with no evidence of erosion of the adjacent
Case report The patient was a lO-year-old female who had received orthodontic treatment at our School of Dentistry over a 178 Dentomaxillofac. Radiol., 1990, Vol. 19, November
Figure 1 Lateral cephalometric radiograph showing a dome-shaped radiopacity in the region of the sphenoid sinus, extending close to the lower border of the sella turcica
© 1990 Butterworth-Heinemann for IADMFR 0250-832 x 90/040178-{)3
Sphenoid mucous cyst: A.G. Farman and I. Baker
Figure 2 Lateral cephalometric radiograph taken 15 months before that shown in Figure 1. Note that the lesion was present at that time, albeit much smaller in size
bony walls. A tentative diagnosis of sphenoid sinus mucous cyst was made. The patient was referred to an otorhinolaryngologist for further investigation when the diagnosis of sphenoid sinus mucous cyst was confirmed following a thorough clinicopathological evaluation. The patient remains asymptomatic 10 months following intervention.
Figure 4 Linear tomography in the midsagittal plane clearly demonstrates the outline and extent of the lesion, the proximity of the soft tissue mass to the sella turcica, and the lack of erosion of adjacent structures. The presence of an air space within the sinus makes this a mucous cyst rather than a mucocele
Discussion This case clearly illustrates the need to examine all parts of a radiograph with care, even when the radiograph is taken for such a routine purpose as orthodontic treatment planning in an asymptomatic patient. This cautionary tale ended well; the lesion did not progress to the formation of a mucocele, without any of the serious consequences that can occur through lack of early diagnosis and treatment of a mucous cyst. As orthodontists will necessarily tend to concentrate on cephalometric measurements, it is recommended that all extra-oral radiographs are referred to a radiologist to exclude any other findings that may be present. The histopathological appearance of the sphenoid sinus mucous cyst is unremarkable, consisting of accumulation of fluid or mucous secretions within unlined connective tissue spaces beneath the unaltered or flattened epithelial lining of the sinus 12. If infection occurs, it is called a 'pyocele' 13. If complete blockage of the ostium occurs, then this can lead to increased intracavitary pressure with flattening of the normal pseudostratified columnar ciliated epithelial appearance 14. The theoretical difference between the mucocele and the large mucous cyst is that no air margin remains between the mucous mass and the sinus wa1l13. This short report does not seek to detail the management of sphenoid sinus mucous cysts and mucoceles. Several excellent reports already exist in the literature 15-17.
References
Figure 3 Submentovertex view proving the lesion to be within, rather than merely superimposed on, the sphenoid sinus
1. Ohba T, Manson-Hing LR. Radiological study of cyst-like lesions in the maxillary sinus. Dentomaxillofac Radial 1975; 4: 100-3. 2. Ruprecht A. Rupture of a mucous retention cyst. Oral Surg Oral Med Oral Pathal 1990; 70 (in press).
Dentomaxillofac. Radiol., 1990, Vol. 19, November
179
Sphenoid mucous cyst: A. G. Farman and I. Baker 3. Eisele DW, Crane RD, Thomas yc. Magnetic resonance imaging of sphenoethmoidal mucoceles. Ear Nose Throat 1988; 67: 713, 716-8, 720. 4. Shitkowitz MJ, Goldstein NM, Stegnjajic A. Sphenoid sinus mucocele masquerading as a skull base malignancy. Laryngoscope 1986; 96: 1405-10. 5. Blum ME, Larson A. Mucocele of the sphenoid sinus with sudden blindness. Laryngoscope 1973; 83: 2043. 6. Lundgren A, Olin T. Muco-pyocele of the sphenoidal sinus or posterior ethmoidal cells with special reference to the apex orbitae syndrome. Acta Otolaryngol1961; 53: 61-79. 7. Maisel RH, EI Deeb M, Bone RC. Sphenoid sinus mucoceles. Laryngoscope 1973; 83: 930-9. 8. Nugent GR, Sprinkle P, Bloor BM. Sphenoid sinus mucoceles. J Neurosurg 1970; 32: 443-51. 9. Johnson LN, Hepler RS, Yee RD, Batzdorf U. Sphenoid sinus mucocele (anterior clinoid variant) mimicking diabetic ophthalmoplegia and retrobulbar neuritis. Am J Op!lthalmoI1986; 102: 111-15. 10. Close LG, O'Connor WE. Sphenoethmoidal mucoceles with intracranial extension. Otolaryngol Head Neck Surg 1983; 91: 350-7.
180 Dentomaxillofac. Radiol., 1990, Vol. 19, November
11. Costa LS, Resende LA. Sphenoid sinus mucocele: an infrequent finding. Arch NeuroI1984; 41: 897-8. 12. Hoffman S, Jacoway JR, Krolls SO. lntraosseous and paraosteal tumours of the jaws, 2nd Series. Washington, DC: Armed Forces Institute of Pathology, 1987. 13. Som PM. The paranasal sinuses. In: Bergeron RT, Osborn AG, Som PM, eds. Head and neck imaging. St. Louis: CV Mosby, 1984. 14. Hyams VJ, Batsakis JG, Michaels L. Tumors of the upper respiratory tract and ear, 2nd Series. Washington, DC: Armed Forces Institute of Pathology, 1988. 15. Stankiewicz JA. Sphenoid sinus mucocele. Arch Otolaryngol Head Neck Surg 1989; 115: 735-40. 16. Ghorayeb BY. Sphenoidotomy. Head Neck Surg 1987; 9: 244. 17. Wilberger JE, Abla A, Kennerdell J, Maroon JC. Mucocele of the pterygoid recess treated by laser surgery. J Neurosurg 1985; 63: 970-2.
Address: Dr A.G. Farman, Professor of Oral and Maxillofacial Radiology, School of Dentistry, University of Louisville, Louisville, KY 40292, USA.
Received 24 January 1990 and in final form 19 April 1990 Sphenoid sinus mucous cysts are rare, benign, expansile masses, which can form mucoceles if the entire sinus is filled. Due to their close proximity to numerous important anatomical structures, they can cause a variety of different symptoms. The incidental finding of a sphenoid sinus mucous cyst during cephalometric radiology for orthodontic analysis is reported. Keywords: Mucocele; sphenoid sinus; radiography, dental
Oral and maxillofacial radiologists are generally familiar with the 'mucocele' of the maxillary sinus. This is frequently seen as an incidental finding on both periapical views of the maxillary posterior teeth and panoramic radiography as a dome-shaped lesion. It is usually asymptomatic and rarely further requires patient referral or treatment 1. As these lesions do not generally fill the whole maxillary sinus, they are perhaps better termed 'mucous cysts' or 'mucous extravasation phenomena' to conform with the accepted nomenclature in the medical radiology literature. The pathogenesis appears to be that of a mucoid collection beneath the lining epithelium of the sinus rather than a retention phenomenon within dilated ducts of mucous glands. If left untreated, they may resolvej. In comparison with 'mucoceles' of the maxillary sinus, those of the sphenoid sinus are uncommon. Sphenoethmoidal mucoceles are benign, expansile masses; however, they can also be locally destructive, and this fact has sometimes led to their being misdiagnosed as a malignant neoplasm/-". Furthermore, the sphenoid sinus is closely related to many important anatomical structures and their compression can lead to a variety of signs and symptoms. Such presentations include frontal or retro-orbital headache and visual abnormalities such as ocular field defects, o~hthalmo plegia, proptosis, and even sudden blindness ,6. Other features reported have been nasal obstruction, rhinorrhea, anosmia, dysfunction of the third through sixth cranial nerve supplies and various endocrine disorders including diabetes 7-9. Intracranial extension of the mucocele per se is extremely rare 10, J I . In view of the infrequency of occurrence of sphenoid sinus mucous cysts, the paucity of reports in the oral and maxillofacial radiology literature, and the potential serious consequences of such lesions if they are allowed to develop into mucoceles, a case is illustrated which was an incidental finding on cephalometric radiography in the course of orthodontic treatment.
IS-month period. A lateral cephalometric radiograph to evaluate both growth and progress of treatment, revealed a well defined, oval-shaped, radiopaque mass in the region of, or superimposed upon, the sphenoid sinus, its upper extension appearing 1.5 mm below the shadow of the sella turcica (Figure 1). Retrospective review of the initial cephalometric radiograph taken 15 months earlier showed a much smaller mass in the same site with its upper extension only 5 mm below the shadow of the sella turcica (Figure 2). Physical examination of the head and neck did not reveal any abnormality. The patient's medical and dental histories were non-contributory and the patient denied symptoms that could be attributed to the radiological findings. A submentovertex radiograph was taken to further localize the radiopaque mass (Figure 3). This confirmed it was in the sphenoid sinus and extended across its whole floor. Linear tomography in the mid-sagittal plane (Figure 4) clearly demonstrated the lesion to be dome shaped and well demarcated without a cortical outline and with no evidence of erosion of the adjacent
Case report The patient was a lO-year-old female who had received orthodontic treatment at our School of Dentistry over a 178 Dentomaxillofac. Radiol., 1990, Vol. 19, November
Figure 1 Lateral cephalometric radiograph showing a dome-shaped radiopacity in the region of the sphenoid sinus, extending close to the lower border of the sella turcica
© 1990 Butterworth-Heinemann for IADMFR 0250-832 x 90/040178-{)3
Sphenoid mucous cyst: A.G. Farman and I. Baker
Figure 2 Lateral cephalometric radiograph taken 15 months before that shown in Figure 1. Note that the lesion was present at that time, albeit much smaller in size
bony walls. A tentative diagnosis of sphenoid sinus mucous cyst was made. The patient was referred to an otorhinolaryngologist for further investigation when the diagnosis of sphenoid sinus mucous cyst was confirmed following a thorough clinicopathological evaluation. The patient remains asymptomatic 10 months following intervention.
Figure 4 Linear tomography in the midsagittal plane clearly demonstrates the outline and extent of the lesion, the proximity of the soft tissue mass to the sella turcica, and the lack of erosion of adjacent structures. The presence of an air space within the sinus makes this a mucous cyst rather than a mucocele
Discussion This case clearly illustrates the need to examine all parts of a radiograph with care, even when the radiograph is taken for such a routine purpose as orthodontic treatment planning in an asymptomatic patient. This cautionary tale ended well; the lesion did not progress to the formation of a mucocele, without any of the serious consequences that can occur through lack of early diagnosis and treatment of a mucous cyst. As orthodontists will necessarily tend to concentrate on cephalometric measurements, it is recommended that all extra-oral radiographs are referred to a radiologist to exclude any other findings that may be present. The histopathological appearance of the sphenoid sinus mucous cyst is unremarkable, consisting of accumulation of fluid or mucous secretions within unlined connective tissue spaces beneath the unaltered or flattened epithelial lining of the sinus 12. If infection occurs, it is called a 'pyocele' 13. If complete blockage of the ostium occurs, then this can lead to increased intracavitary pressure with flattening of the normal pseudostratified columnar ciliated epithelial appearance 14. The theoretical difference between the mucocele and the large mucous cyst is that no air margin remains between the mucous mass and the sinus wa1l13. This short report does not seek to detail the management of sphenoid sinus mucous cysts and mucoceles. Several excellent reports already exist in the literature 15-17.
References
Figure 3 Submentovertex view proving the lesion to be within, rather than merely superimposed on, the sphenoid sinus
1. Ohba T, Manson-Hing LR. Radiological study of cyst-like lesions in the maxillary sinus. Dentomaxillofac Radial 1975; 4: 100-3. 2. Ruprecht A. Rupture of a mucous retention cyst. Oral Surg Oral Med Oral Pathal 1990; 70 (in press).
Dentomaxillofac. Radiol., 1990, Vol. 19, November
179
Sphenoid mucous cyst: A. G. Farman and I. Baker 3. Eisele DW, Crane RD, Thomas yc. Magnetic resonance imaging of sphenoethmoidal mucoceles. Ear Nose Throat 1988; 67: 713, 716-8, 720. 4. Shitkowitz MJ, Goldstein NM, Stegnjajic A. Sphenoid sinus mucocele masquerading as a skull base malignancy. Laryngoscope 1986; 96: 1405-10. 5. Blum ME, Larson A. Mucocele of the sphenoid sinus with sudden blindness. Laryngoscope 1973; 83: 2043. 6. Lundgren A, Olin T. Muco-pyocele of the sphenoidal sinus or posterior ethmoidal cells with special reference to the apex orbitae syndrome. Acta Otolaryngol1961; 53: 61-79. 7. Maisel RH, EI Deeb M, Bone RC. Sphenoid sinus mucoceles. Laryngoscope 1973; 83: 930-9. 8. Nugent GR, Sprinkle P, Bloor BM. Sphenoid sinus mucoceles. J Neurosurg 1970; 32: 443-51. 9. Johnson LN, Hepler RS, Yee RD, Batzdorf U. Sphenoid sinus mucocele (anterior clinoid variant) mimicking diabetic ophthalmoplegia and retrobulbar neuritis. Am J Op!lthalmoI1986; 102: 111-15. 10. Close LG, O'Connor WE. Sphenoethmoidal mucoceles with intracranial extension. Otolaryngol Head Neck Surg 1983; 91: 350-7.
180 Dentomaxillofac. Radiol., 1990, Vol. 19, November
11. Costa LS, Resende LA. Sphenoid sinus mucocele: an infrequent finding. Arch NeuroI1984; 41: 897-8. 12. Hoffman S, Jacoway JR, Krolls SO. lntraosseous and paraosteal tumours of the jaws, 2nd Series. Washington, DC: Armed Forces Institute of Pathology, 1987. 13. Som PM. The paranasal sinuses. In: Bergeron RT, Osborn AG, Som PM, eds. Head and neck imaging. St. Louis: CV Mosby, 1984. 14. Hyams VJ, Batsakis JG, Michaels L. Tumors of the upper respiratory tract and ear, 2nd Series. Washington, DC: Armed Forces Institute of Pathology, 1988. 15. Stankiewicz JA. Sphenoid sinus mucocele. Arch Otolaryngol Head Neck Surg 1989; 115: 735-40. 16. Ghorayeb BY. Sphenoidotomy. Head Neck Surg 1987; 9: 244. 17. Wilberger JE, Abla A, Kennerdell J, Maroon JC. Mucocele of the pterygoid recess treated by laser surgery. J Neurosurg 1985; 63: 970-2.
Address: Dr A.G. Farman, Professor of Oral and Maxillofacial Radiology, School of Dentistry, University of Louisville, Louisville, KY 40292, USA.
