Pneumosinus dilatans of the sphenoid sinus

Four cases of pneumosinus dilatans of the sphenoid sinus are reported, supplementing the eight cases previously reported in the literature. This rare entity is characterized by expansion of a paranasal sinus that contains only air. In one patient, severe visual loss due to compression of the optic canal by the adjacent enlarged sinus was seen. Galactorrhea occurred in one patient, and three of the four patients reported headaches. There was dehiscence of the sinus roof in two cases, which apparently resulted in a cerebrospinal fluid fistula in one. Previous reports of this entity are reviewed, and the radiographic findings and clinical presentations are discussed. It is proposed that the term "pneumosinus dilatans" be used to describe all dilated, air-filled sinuses with outwardly bulging walls when the primary cause is uncertain.     

Orbital pneumosinus dilatans

Pneumosinus dilatans consists of an abnormal dilatation of the paranasal air sinuses which contain air only and are lined by normal epithelium. The condition is most commonly observed when it affects the sphenoid sinus as a response to a local meningioma of the tuberculum sellae or planum sphenoidale. Pneumosinus dilatans affecting the walls of the paranasal sinuses which form the boundaries of the orbit is less common; six patients reported here presented with either unilateral or bilateral exophthalmos. The frontal sinus and ethmoid cells were affected unilaterally in four patients and the maxillary antra bilaterally in two. The condition was associated with a meningioma in three patients and fibro-osseous disease in three patients. The importance of recognising this condition is in alerting the radiologist to the possible presence of an occult meningioma requiring soft-tissue imaging techniques (computed tomography or nuclear magnetic resonance imaging). The presence of fibro-osseous disease can usually be recognised by plain radiography.     

Pneumosinus dilatans of the ethmoid sinus presenting with exophthalmus: a case report and review of the literature

Pneumosinus dilatans (PSD) is a rare condition of unknown aetiology in which there is enlargement of the paranasal sinuses by air, where the affected sinus expands beyond the normal boundaries of bone without thinning of its bony walls. The case of a 28 year old male with PSD, who had gradually increasing exophthalmus and diplopia, is presented and characteristics of this condition are reviewed with literature data.     

Sphenoid pneumosinus dilatans a sign of meningioma originating in the optic canal

Summary Surgical exploration of three patients who had a radiological diagnosis of sphenoid pneumosinus dilatans disclosed an intracanalicular meningioma of the sheath of the optic nerve (MSON), bilaterally in two patients and unilaterally in the other. Two cases of sphenoid pneumosinus dilatans, previously reported, are reviewed, and a new case is presented. The relationship of sphenoid pneumosinus to MSON is discussed. Sphernoid pneumosinus dilatans may be an early sign of MSON in the optic canals or at the optic foramens.This paper was presented in part at the 10th Annual Neuro-Ophthalmic Pathology Conference, Baltimore, Maryland, 16–17 February 1979.     

Sphenoidal pneumosinus dilatans: a case report (author's transl)

Pneumosinus dilatans is an abnormal dilatation of a paranasal cavity containing air only. The case described here can be added to the 51 cases in the literature. Various pathogenetic theories have been proposed: mucocele, intrasinus hypertension, inflammation, endocrine disorder. The authors suggest that this pathological form is the result of overextension of a normal process in the morphogenesis of the sinuses. The symptomatology depends on the location and on the rate of onset of the dilatation.     

Sinonasal computed tomography in patients with Wegener's granulomatosis

The goal of this study was to describe pathologies of sinonasal CT in patients with Wegener's granulomatosis. Between 1993 and 2004, sinonasal CT was performed in 28 patients (15 male, 13 female) with Wegener's granulomatosis. The following imaging findings were assessed on the CT scans: mucosal thickening, subtotal opacification, air-fluid level, bony destruction, sclerosing osteitis, bony thickening, orbital mass, and saddle nose deformity. Of the 28 patients, 61% showed mucosal thickening in the nasal cavity and 75% in the paranasal sinuses. A subtotal opacification of the paranasal sinuses was detected in 25%, and of the mastoid cells in 7% of patients. Fifty-seven percent of patients had bony destruction of the nasal cavity, and 54% of the paranasal sinuses. CT revealed sclerosing osteitis of the paranasal sinuses in 21%, and of the mastoid cells in 18% of patients. Bony thickening of the paranasal sinuses was detected in 18%, and of the mastoid cells in 14% of patients. With respect to all imaging findings, the maxillary sinuses were the most frequently affected paranasal sinuses. The authors conclude that the following sinonasal CT findings are observed in patients with Wegener's granulomatosis: (1) bony destruction, mainly of the nasal cavity, maxillary sinuses, and mastoid cells; (2) sclerosing osteitis, mainly of the maxillary sinuses and mastoid cells; (3) bony thickening, mainly of the maxillary sinuses and mastoid cells; and (4) mucosal thickening, mainly of the maxillary sinuses. These findings are, however, nonspecific and should be combined with other clinicopathologic and laboratory studies to confirm the diagnosis of Wegener's granulomatosis.     

Radium-induced malignant tumors of the mastoid and paranasal sinuses.

In the records of 5,058 persons with therapeutic or occupational exposure to radium, 21 patients with carcinoma of the mastoid and 11 with malignant tumors of the paranasal sinuses were identified. Tumor induction times were 21-50 years for mastoid tumors (median, 33) and 19-52 years for paranasal sinus tumors (median, 34). Dosimetric data are given for the patients whose body burdens of radium have been measured. We found a high proportion of mucoepidermoid carcinoma, comprising 38% of the mastoid and 36% of the paranasal sinus tumors. Three patients had antecedent bone sarcoma at 20, 11, and 5 years, respectively, and a bone sarcoma was discovered at autopsy in a fourth patient. Radiographic changes in the mastoid and paranasal sinuses were similar to those seen in nonradium malignant tumors. More than 800 known persons exposed to radium before 1930 and another group of unknown size who received radium water or injections of radium from physicians are still alive and at risk of developing malignant tumors of the mastoid and paranasal sinuses.     

Pneumosinus dilatans in anterior skull base meningiomas

Introduction

Skull base meningiomas are often missed on non-contrast CT or MR examinations due to their close proximity to bone and low lesion to brain contrast. The purpose of this study is to illustrate that pneumosinus dilatans can be an indicator of anterior skull base meningiomas.

Methods

A retrospective search of the radiology information system and picture archiving and computing system database was performed. Search terms were “meningioma” in association with “pneumosinus dilatans.” Medical records and imaging studies were reviewed independently by two experienced neuroradiologists and were read in consensus. We recorded the patient age at the time of discovery of the meningioma, main presenting symptom(s), location of the tumor, and imaging characteristics. We also performed a comparative literature search for pneumosinus dilatans and its association with meningiomas.

Results

Ten patients (six women; four men) were identified in whom a meningioma of the anterior skull base was associated with a pneumosinus dilatans. Three patients had multiple meningiomas, so a total of 14 intracranial tumors were identified. Mean age at discovery was 59 years with an age range of ±20 years. All meningiomas were diagnosed by MRI and/or CT.

Conclusion

Pneumosinus dilatans can be a helpful sign to indicate the presence of a meningioma of the anterior skull base.     

Imaging of Sturge-Weber syndrome: cranial CT and MR findings

Sturge-Weber syndrome (SWS) is a phakomatosis characterized by vascular nevus flammeus, leptomeningeal venous angiomatosis, seizures, dementia, hemiplegia, hemianopsia, and glaucoma. Various imaging findings (gyriform calcification, atrophy of the ipsilateral hemisphere, leptomeningeal enhancement, ipsilateral choroid plexus enlargement, thickened calvarium, enlargement of paranasal sinuses and mastoid air cells, enlargement of deep veins, and white matter change adjacent to leptomeningeal enhancement) are seen in SWS. We examined the efficacy of CT and MR imaging in making the diagnosis in 14 patients. All patients underwent CT and MRI, and 11 of 14 patients underwent contrast-enhanced MRI. The most specific finding was leptomeningeal enhancement. Gyriform calcification, atrophy of the ipsilateral hemisphere, and ipsilateral chroid plexus enlargement were seen at high frequencies. Thickened calvarium was more frequent in adult patients. Enlargement of paranasal sinuses and mastoid air cells, enlargement of deep veins, and white matter change adjacent to leptomeningeal enhancement were seen in some (3-5) patients. A combination of findings of plain CT and MRI (including postcontrast MRI and MR venography) are useful for diagnosing SWS.     

Common and unusual craniofacial manifestations of metastatic neuroblastoma

Although neuroblastoma is a common childhood malignancy, which frequently metastasizes, involvement of the facial bones and paranasal sinuses are uncommonly reported in the literature. However, over the last several years, we have encountered an increasing number of cases of metastatic neuroblastoma to the central nervous system and head and neck. This article will review the common and uncommon imaging manifestations of metastatic neuroblastoma, with emphasis on the orbits, maxillofacial bones, and paranasal sinuses.     

Apparent paradoxical vault changes with middle cranial fossa arachnoid cysts--implication for aetiology

Three cases of middle cranial fossa arachnoid cyst with paradoxical bone changes in the adjacent vault are described, namely, a small middle cranial fossa and pneumosinus dilatans. This association is unusual and unique. The existing literature is reviewed and the probable aetiological factors discussed.     

Computed tomography of osteogenic sarcoma of nasal cavity and paranasal sinuses

Computed tomography was performed in four patients with osteogenic sarcoma of the nasal cavity and paranasal sinuses. In all cases CT demonstrated an abnormal soft tissue mass with associated aggressive bony destruction. In only one case were areas of calcification and new bone formation identified, allowing a preoperative diagnosis. The CT appearance of these four patients plus an additional four cases previously reported in the literature are reviewed.     

Virtual autopsy: two- and three-dimensional multidetector CT findings in drowning with autopsy comparison

PURPOSE: To retrospectively determine the multidetector computed tomographic (CT) virtual autopsy findings of death by drowning in comparison with autopsy findings. MATERIALS AND METHODS: The institutional review board of the Armed Forces Institute of Pathology approved this HIPAA-compliant study and did not require informed consent by the next of kin. Total-body multidetector CT was performed, immediately prior to routine autopsy, in 28 consecutive male subjects (mean age, 24.2 years) who died of drowning and a control group of 12 consecutive male subjects (mean age, 50.8 years) who died of sudden death from atherosclerotic coronary artery disease. Images were evaluated for the presence of fluid and sediment in the paranasal sinuses and airways, mastoid air cell fluid, frothy fluid in the airways, pulmonary opacity (ground-glass opacity or airspace consolidation), interlobular septal thickening, and gastric distention and contents (fluid or sediment). Image findings were compared with findings from autopsy reports and photographs. RESULTS: All drowning subjects had fluid in the paranasal sinuses and mastoid air cells and had ground-glass opacity within the lungs. Twenty-six subjects (93%) had fluid in the subglottic trachea and main bronchi. Fourteen subjects (50%) had high-attenuation sediment in the subglottic airways. Frothy fluid in the airways was present in six subjects (21%). Twenty-five (89%) of the drowning subjects had pulmonary ground-glass opacity with septal lines, which was mild with apical and perihilar distribution in 12 subjects, severe and diffuse in nine, posterior and basilar in three, and limited to the apices in one (not assessed in three of 28 subjects because of decomposition). Control subjects showed mastoid cell fluid (25%), sinus fluid (83%), subglottic airway fluid (92%), and pulmonary ground-glass opacity (100%) but did not have evidence of frothy airway fluid or high-attenuation sediment in the airways. CONCLUSION: The multidetector CT finding of frothy airway fluid or high-attenuation airway sediment is highly suggestive of drowning; multidetector CT findings of pan sinus fluid, mastoid cell fluid, subglottic tracheal and bronchial fluid, and ground-glass opacity within the lung at multidetector CT are supportive of drowning in the appropriate scenario.     

CT findings in involvement of the paranasal sinuses by lepromatous leprosy.

The role of nasal infection in the transmission of leprosy has been extensively studied. Leprosy can affect the paranasal sinuses due to mucosal continuity and bacillaemia. This prospective study was performed on 25 untreated patients with lepromatous leprosy. 5 mm contiguous axial and coronal CT sections of paranasal sinuses, on soft tissue and bone windows, were obtained in all patients. Each sinus was examined for mucosal thickening, soft tissue densities and bony outlines. Representative biopsies were taken from ethmoid sinus to confirm the radiological diagnosis in 12 patients with multiple paranasal sinus involvement. Ethmoid aircells were involved in 20 patients (80%). Maxillary, frontal and sphenoid sinuses showed abnormalities in 12, four and three patients, respectively. The ethmoid biopsy showed involvement by lepromatous leprosy in seven of 12 patients (58.3%). Involvement of paranasal sinuses is common in lepromatous leprosy and is of considerable epidemiological significance.     

Lymphoma of nasal and sinus cavities

Seven cases of non-Hodgkin lymphoma of the nasal cavities and paranasal sinuses are reported. All but one were primary lesions. Five of the 7 cases involved only the facial structures. Sites of involvement were the maxillary sinus (4 cases), the nasal fossae (2 cases), and one case in which lesions of both the ethmoid and sphenoid sinuses were associated with intracranial extension. CT studies showed sinus opacification and invasion of adjacent structures, but bone destruction was inconstant. Follow-up studies during treatment revealed rapid tumor regression with non specific images of mucosal hypertrophy.     

Role of Mastoid Pneumatization in Temporal Bone Fractures

BACKGROUND AND PURPOSE:The mastoid portion of the temporal bone has multiple functional roles in the organism, including regulation of pressure in the middle ear and protection of the inner ear. We investigated whether mastoid pneumatization plays a role in the protection of vital structures in the temporal bone during direct lateral trauma.MATERIAL AND METHODS:The study was performed on 20 human temporal bones isolated from cadavers. In the study group formed by 10 temporal bone samples, mastoid cells were removed and the resulting neocavities were filled. The mastoids were maintained intact in the control group. All samples were impacted at the same speed and kinetic energy. The resultant temporal bone fractures were evaluated by CT.RESULTS:Temporal squama fractures were 2.88 times more frequent, and mastoid fractures were 2.76 times more frequent in the study group. Facial nerve canal fractures were 6 times more frequent in the study group and involved all the segments of the facial nerve. Carotid canal fractures and jugular foramen fractures were 2.33 and 2.5 times, respectively, more frequent in the study group.CONCLUSIONS:The mastoid portion of the temporal bone plays a role in the absorption and dispersion of kinetic energy during direct lateral trauma to the temporal bone, reducing the incidence of fracture in the setting of direct trauma.

The mastoid portion of the temporal bone has a pneumatic structure similar to that of the paranasal sinuses. While pneumatized paranasal structures have developed phylogenetically because of multiple functional needs,¹ however, the functional roles of the mastoid are discussed less in the literature. Hill and Richtsmeier² designated pneumatic cells in the temporal bone as enigmatic structures. They showed that temporal bone pneumatization has diminished during the evolution of the human species, but little is known about the cause or effect of this process.² Mastoid cells are completely formed around 10 years of age and reach maturity between 15 and 20 years of age.^3,4 In the adult, there are no differences in the size of the mastoid between men and women.⁵ Also, Han et al⁶ found no statistically significant differences in mastoid pneumatization between the right and left side. The size of mastoid cells is not only determined genetically, but environmental factors are also involved. The volume of mastoid cells depends on the degree of impairment of the middle ear during childhood, such as recurrent acute otitis media or otitis media with effusion.⁷ Turgut and Tos⁸ found mastoid length to be significantly shorter in specimens with pathologic eardrum and middle ear adhesions. Pneumatization was also decreased in specimens with a short length of the mastoid process. However, it is not clear whether reduced temporal bone pneumatization is the effect of middle ear infections or their cause.Kellman and Schmidt¹ demonstrated the role of the paranasal sinuses in the protection of the eyeball. They showed that a direct blow on the eyeball causes fracture of the orbit floor, while the eyeball remains intact. In contrast, if the paranasal sinuses are filled with bone cement, direct eye trauma causes rupture of the eyeball, without orbit fractures.¹We hypothesize that mastoid pneumatization plays a role similar to that of the paranasal sinuses: to protect vital structures such as the facial nerve, blood vessels, and central nervous tissue, by dissipating energy.     

Incidence of non-tumor anomalies of the facial sinuses on x-ray computed tomography of the brain of asymptomatic patients. Clinical and radiologic correlations between involvements of ethmoid cells and other sinus cavities

Two hundred ninety five consecutive brain CT examinations of asymptomatic adults were studied prospectively for detection of nontumoral paranasal sinus abnormalities. CT alterations were found in 104 cases (35.3%), localized to the ethmoid cells in 83 cases, the maxillary sinuses in 56 cases, the sphenoid sinuses in 19 cases, and the frontal sinuses in 18 cases. The relationships between ethmoid cells disease and alterations of the large paranasal cavities are analysed, and the association with previous sinusitis or rhinitis is evaluated. Frontal sinus disease is associated in more than two-thirds of the cases with pathologic meatic and/or unciform ethmoid cells, but such an association could not be demonstrated for the other cavities.     

Arachnoid cyst of the middle fossa with paradoxical changes of the bony structures

Summary Two patients with an arachnoid cyst of the middle fossa showed paradoxical changes of the adjoining bony structures of the skull. There was a diminution of the middle fossa and hyperplasia of the sphenoid sinus (pneumosinus dilatans) as well as a marked bulging of the squamous part of the temporal bone. In one case in which scinticisternography was performed, communication between the cyst and the subarachnoidal space was proven as well as an extremely slow cerebrospinal fluid circulation in the cyst. The pathogenesis of the cyst is discussed, based upon the structural changes of the skull, the angiographic findings and the locally disturbed cerebrospinal fluid circulation. The primary disturbance seems to be a temporal lobe agenesis.     

鼻咽癌侵犯鼻窦的MRI表现(附86例病例分析)

目的：分析鼻咽癌侵犯鼻窦的磁共振（MRI）表现,探讨MRI在诊断鼻咽癌侵犯鼻窦中的作用。方法：回顾分析鼻咽癌并鼻窦侵犯的86例患者的MRI表现。结果：MRI表现为窦壁破坏100%,窦壁黏膜增厚52.3%,窦腔内软组织肿块65.1%,鼻窦内侵犯病灶与鼻咽肿瘤相连97.7%,合并积液25.6%。横断面T1WI、T2WI、CE-T1WI所示病灶三者间差异无显著性意义,矢状面T1WI、冠状面FSIR和冠状面CE-T1WI示肿瘤侵犯蝶窦为100%,横断面T2WI和CE-T1WI对显示筛窦、上颌窦受侵最佳。结论：窦壁骨质破坏、连续性中断;窦壁黏膜不均匀性增厚;窦腔内肿块与鼻咽肿瘤主体相连,且有相同程度的强化;T1WI呈等或稍低信号,T2WI为等或稍高信号;增强扫描明显强化,是诊断鼻窦受侵犯的要点。因此,MRI的横断面T2WI、矢状面T1WI、冠状面FSIR及增强扫描在鼻咽癌鼻窦受侵犯的诊断中作用较大。     

鼻咽腺样体肥大的CT诊断

目的:探讨鼻咽腺样体肥大的CT表现及其鉴别诊断。方法:分析30例鼻咽腺样体肥大的CT表现,重点观察病变部位、咽旁软组织间隙、副鼻窦及乳突改变。结果:鼻咽顶壁和后壁软组织增厚,弥漫性向前下突出22例,呈山丘样突出8例,伴有双侧咽鼓管口淋巴组织增生及副鼻窦炎9例,伴中耳乳突炎5例,伴面骨发育障碍牙列不齐,堵塞后鼻孔2例。结论:鼻咽腺样体肥大不累及咽缝,无咽旁间隙侵犯。