Lobulated Schwannoma of the Median Nerve

Diagnosing Schwannoma in the Wrist: a Challenging Case of Intraneural Ganglion Cyst Mimicry and a Review of Literature

Schwannoma can rarely mimic an intraneural ganglion cyst clinically and radiographically. This is a rare case report of a wrist schwannoma mimicking an intraneural ganglion cyst. The surgery was successful, and the histopathological report confirmed the diagnosis of benign schwannoma. After two years of follow-up, the patient is still symptom-free.

Ancient schwannoma of the hand

Ancient schwannoma is a schwannoma subtype, characterized by extensive degeneration and diffuse hypocellular areas. These changes are believed to occur because it takes a long time for ancient schwannomas to develop. Schwannomas with these degenerative changes can be misdiagnosed as sarcomas or other soft-tissue neoplasms. We present a case of a slowly enlarging ancient schwannoma of the thenar area in a 67-year-old woman. The differential diagnosis included atypical soft tissue sarcomas and tumors of neural origin. The combination of ultrasound and magnetic resonance imaging findings provided features that narrowed the differential diagnosis, and histology confirmed the presence of an encapsulated schwannoma with extensive myxomatous degeneration and multiple vessel thrombosis. The clinical, radiological, and histological features and the diagnostic approach of this rare entity are described.

Use of routine histologic evaluation of carpal ganglions

PURPOSE

Although histologic evaluation is performed routinely on tissue removed during the excision of carpal ganglions, the necessity of this evaluation is uncertain. We evaluated the use of routine histologic evaluation of excised carpal ganglions and performed a cost-benefit analysis.

METHODS

A retrospective review identified 160 consecutive carpal ganglion (102 dorsal, 58 volar) excisions performed over the past 7 years by 2 surgeons. The preoperative evaluation, surgical findings, and results of the pathologic assessment were evaluated for patients treated with a typical carpal ganglion excision.

RESULTS

In 156 of 160 patients the preoperative and intraoperative data were highly suggestive of a carpal ganglion; the pathology reports confirmed the diagnosis in all of these patients. No new information was provided by pathologic assessment. In 4 patients the preoperative and intraoperative assessments were less certain; the pathologic assessments in these patients also were equivocal. No malignancy or condition requiring additional treatment was identified. At our institution the total cost of pathologic evaluation for a carpal ganglion including processing and interpretation fees is $352.

CONCLUSIONS

Routine histologic examination of excised dorsal and volar carpal ganglions may be unnecessary if the preoperative and intraoperative evaluations are consistent with a diagnosis of carpal ganglion.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic, Level IV.