Sphenoid sinus schwannoma with adhesion to the carotid canal

Few reports have been made on the presentation and treatment of schwannomas originating in the sphenoid sinus due to their rarity. We report the case of a 60-year-old woman who presented with a cyst-like mass in the right sphenoid sinus on magnetic resonance imaging. Computed tomography showed a bone defect in the internal carotid artery (ICA) and enlargement of the round foramen on the affected side. A histopathological diagnosis of schwannoma was made, and endoscopic sinus surgery was performed. The anterior part of the tumor could be easily removed by aspiration; however, its adhesion to the ICA was remarkable, and its boundaries were unclear. Although partial paralysis of the maxillary nerve remained, no recurrence occurred for over 10 years. Careful evaluation should be performed to check for bone defects in the nerve to differentially diagnose schwannoma from cystic masses of the sphenoid sinus. Additionally, excision of masses similar to the presented case may expectedly be difficult because of unclear excisional margins and strong capsule adherence to important organs such as the ICA. Moreover, correct imaging, histopathological diagnosis, and appropriate informed consent are essential before surgery.

Fluid-fluid Levels in Musculoskeletal Tumor Imaging

Fluid-fluid levels result from the separation of two fluids of differing densities within a cavernous space with the boundary between the two layers running in a horizontal plane at 90 degrees to the direction of gravity. Magnetic resonance imaging is the most sensitive imaging modality to identify fluid-fluid levels. Although the most common bone lesions containing fluid-fluid levels are aneurysmal bone cyst and telangiectatic osteosarcoma, fluid-fluid levels can be observed in a wide variety of bone and soft tissue lesions. Therefore, fluid-fluid levels cannot be considered diagnostic of any particular type of tumor and the diagnosis should be made on the basis of other clinical, radiological and pathological findings. This article summarizes the pathophysiology and imaging characteristics of fluid-fluid levels and discusses the differential diagnosis of tumors with this imaging sign.

Fungus ball within a mucocele of the sphenoid sinus and infratemporal fossa: case report with radiological findings

OBJECTIVE

We report an extremely rare case of a fungus ball within a mucocele of the sphenoid sinus and infratemporal fossa.

CASE REPORT

A 62-year-old woman was referred for evaluation of a mass lesion in the left sphenoid sinus and infratemporal fossa. Endoscopic examination of the nasal cavity was unremarkable. Computed tomography showed a non-enhancing, expansile mass with calcifications in the sphenoid and infratemporal fossa; T2-weighted magnetic resonance imaging revealed marked hypointense signals within the sphenoid sinus mass, with an intermediate signal intensity. A presumptive diagnosis of a mucocele was made. During surgery, a profuse amount of yellow fluid was drained from the mucocele. Clay-like material was noted within the mucocele, corresponding to the hypointense magnetic resonance imaging signals; this was identified as aspergillus on histopathological examination. Radiological findings for a fungus ball within a mucocele can be similar to those for allergic fungal sinusitis, which shows mixed low and high attenuation on computed tomography and low-signal intensity on T2-weighted magnetic resonance imaging, within an expansile, cystic lesion.

CONCLUSION

Although an association between a fungus ball and a mucocele is rare in the paranasal sinuses, this disease entity should be considered in the differential diagnosis of expansile, cystic sinus lesions.

Cystic schwannoma of the maxillary sinus

OBJECTIVE

Although 25-45% of all schwannomas are reported to occur in the head and neck region, nasal cavity and paranasal sinus involvement is rare, with 32 such cases described till 1999. Of these cases, only three were cystic. Herein we present a cystic schwannoma of the maxillary sinus of a 66-year-old, otherwise healthy male patient.

METHODS

The tumor tissue was routinely processed, embedded in paraffin, and stained with H&E. Immunostaining was performed for S-100 protein, epithelial membrane antigen (EMA) and cytokeratin.

RESULTS

A mass with sudden enlargement, inhomogeneous enhancement with cystic areas, S-100 positive membrane-like structures lining the cystic cavity of an otherwise classical schwannoma were the main features encountered in our case.

CONCLUSION

We recommend that cystic schwannoma should be kept in mind in the differential diagnosis of cystic masses of the maxilla.

Extended frontal approach with bilateral orbitofrontoethmoidal osteotomies for removal of a giant extracranial schwannoma in the nasopharynx, sphenoid sinus, and parapharyngeal space

BACKGROUND

Although parapharyngeal schwannomas are not uncommon, schwannomas of the nasopharynx and paranasal sinuses are rare lesions. In the absence of intracranial extension, they are usually removed with transantral, lateral rhinotomy or more complex transfacial approaches.

CASE DESCRIPTION

We report a 24-year-old patient with a giant benign schwannoma involving the superior parapharyngeal space, pterygopalatine fossa, nasopharynx, and sphenoid sinus with erosion into the clivus that was removed with an extended frontal approach including bilateral orbitofrontoethmoidal osteotomies.

CONCLUSION

The advantages of the extended subfrontal over more standard transfacial approaches for lesions in this location include the early dissection of critical neural structures, preserving cosmetics and facilitating management of an inadvertent cerebrospinal fluid leak.

Factors in the pathogenesis of tumors of the sphenoid and maxillary sinuses: a comparative study

OBJECTIVES/HYPOTHESIS

To explain the processes that lead to the development of tumors in the maxillary and sphenoid sinuses.

STUDY DESIGN

A 32-year review of the world's literature on neoplasms of these two sinuses and a randomized case-controlled study comparing the normal mucosal architecture of the maxillary to the sphenoid sinus.

METHODS

Analysis of a 32-year world literature review reporting series of cases of maxillary and sphenoid sinus tumors. Tumors were classified by histological type and separated into subgroups if an individual incidence rate was reported. Histomorphometry of normal maxillary and sphenoid sinus mucosa was performed in 14 randomly selected patients (10 sphenoid and 4 maxillary specimens). Specimens were fixed in 10% formalin, embedded in paraffin, and stained with periodic acid-Schiff (PAS) and hematoxylin. Histomorphometric analysis was performed with a Zeiss Axioscope light microscope (Carl Zeiss Inc., Thornwood, NY) mounted with a Hamamatsu (Hamamatsu Photonics, Tokyo, Japan) color-chilled 3 charge coupled device digital camera. The images were captured on a 17-inch Sony (Sony Corp., Tokyo, Japan) multiscan monitor and analyzed with a Samba 4000 Image Analysis Program (Samba Corp., Los Angeles, CA). Five random areas were selected from strips of epithelium removed from each sinus, and goblet and basal cell measurements were made at magnifications x 100 and x 400.

RESULTS

The literature review revealed that the number and variety of tumors in the maxillary sinus are much greater than those in the sphenoid. The incidence of metastatic lesions to each sinus is approximately equal. No recognized pattern of spread from any particular organ system could be determined. On histomorphometric study there were no statistically significant differences between the sinuses in the concentration of goblet cells, basal cells, or seromucinous glands.

CONCLUSIONS

Factors involved in the pathogenesis of tumors of the maxillary and sphenoid sinuses include differences in nasal physiology, embryology, morphology, and topography. There are no significant histological differences in the epithelium and submucous glands between the two sinuses to explain the dissimilar formation of neoplasms.

Cystic schwannomas of the jugular foramen: clinical and surgical remarks

OBJECTIVE

The goals of this report were to outline the clinical presentation, radiological characteristics, surgical techniques, postoperative morbidity, and long-term follow-up results for cystic jugular foramen (JF) schwannomas and to describe their differences, compared with solid schwannomas involving the JF.

METHODS

A retrospective analysis of radiological studies and surgical records identified five primarily cystic tumors among 21 cases of JF schwannomas that had been surgically treated at our institution.

RESULTS

Two types of cystic JF schwannomas were observed, i.e., Type 1 lesions, which are single large cysts with thin ring-like enhancement of the tumor wall, and Type 2 lesions, which are multiple cysts with very irregular, thick enhancement of the cyst wall. The most common symptoms were hearing loss, ataxia, and headaches. Total surgical removal could be performed in all cases. The immediate postoperative findings indicated hearing improvement in three cases. No deterioration of lower cranial nerve function was observed. All patients were independent in the immediate postoperative period and in the long-term follow-up period (Karnofsky Performance Scale score, 90).

CONCLUSION

Surgical treatment of cystic JF schwannomas can be very demanding because of generally stronger adhesion of the tumor capsule to the surrounding structures, fragile tumor capsules, and difficulty in identification of the arachnoidal planes in some cases. Early identification of the arachnoidal planes without opening of the cyst and sharp dissection may be useful. Careful intradural opening of the JF should be performed to achieve total removal of the last tumor portion within the JF. A comparison of these lesions with solid schwannomas involving the JF indicated that cystic tumors affected a younger population, with less preoperative swallowing impairment (P < 0.05). The immediate postoperative course in both types of cystic JF schwannomas was usually better than for solid lesions, because of minor postoperative cranial nerve morbidity, especially involving lower cranial nerve function, in the latter cases. Long-term follow-up data failed to demonstrate any significant differences in final patient outcomes, however.

Management of Malignant Schwannomas of the Paranasal Sinuses and Anterior Skull Base

The evolution of skull base surgery has facilitated the extirpation of previously unresectable tumors. As experience with skull base surgery increases, the feasibility of resection and long-term outcomes is becoming apparent for the more common lesions. Neoplasms such as malignant schwannomas are rare and, therefore, defy single-institution analysis. The treatment and four-year follow-up of a malignant paranasal sinus and anterior skull base schwannoma is described. Analysis of the literature confirms the low incidence of this tumor and supports the efficacy of skull base surgery in its treatment.