Multiple schwannomas presenting as a mass of the lateral chest wall

Neurilemmoma showing a unique growth pattern in the lateral chest wall: both inside and outside the thoracic cavity

We report the first case of the intercostal neurilemmoma showing a unique growth pattern in the lateral chest wall (both inside and outside the thoracic cavity). Usually, intrathoracic neurilemmoma is found in the posterior mediastinum and bulge from the inner surface of the bony thorax toward the thoracic cavity. This unique growing pattern of neurilemmoma arising from intercostal nerve was clearly demonstrated by computed tomography and ultrasonography.

Multiple unilateral schwannomas: segmental neurofibromatosis type 2 or schwannomatosis?

Schwannomas are benign solitary tumours of the peripheral nerve sheaths. The occurrence of multiple schwannomas usually implies hereditary disease. The most frequent syndrome associated with multiple schwannomas is neurofibromatosis type 2 (NF2), which is defined by bilateral vestibular schwannomas. Schwannomatosis is a distinct disease characterized by multiple pathologically proven schwannomas in the absence of vestibular schwannomas. It is not currently known if the presence of multiple schwannomas confined to a limb may represent a mosaic form of NF2 or a distinct disease, because mutation analysis of these tumours is not routinely performed. We report a 31-year-old patient who presented with multiple slowly growing subcutaneous tumours on his left arm. His family history was negative for cutaneous tumours or central nervous system disease, and he did not have additional features of NF2. Magnetic resonance tomography and ophthalmological examination excluded vestibular schwannoma and eye stigmata of NF2. After resection of three tumours, histological analysis confirmed the diagnosis of benign schwannomas. Molecular genetic analysis by temperature gradient gel electrophoresis and microsatellite marker analysis demonstrated two distinct mutations of the NF2 gene (NF2) in two different schwannomas, with concomitant loss of heterozygosity in both tumours. In contrast, neither normal skin nor peripheral blood lymphocytes revealed mutations of NF2. The clinical and molecular genetic findings suggest that the diagnosis in our patient is schwannomatosis rather than segmental NF2 because the mutations found in different tumours were not identical. The possibility of a localized predisposition for the acquisition of NF2 mutations is discussed.

Multiple schwannomas: schwannomatosis or neurofibromatosis type 2?

OBJECT

The aim of this study was to clarify the clinical outcome of schwannomatosis, a rare condition characterized by multiple nonvestibular schwannomas in the absence of meningiomas, intraspinal ependymomas, and other clinical signs of neurofibromatosis type 2 (NF2).

METHODS

Nine patients with schwannomatosis treated at one institution are presented and their clinical course during a median follow-up time of 9.9 years is discussed. The patients were typically middle-aged at the time of their first operation (median 43.5 years), none had a positive family history of schwannomatosis or NF2, and none showed cutaneous or ocular signs of NF2. On histopathological examination the tumors from the patients with schwannomatosis showed a lobular appearance and frequent Verocay bodies, signs indicating NF2, more often than 20 sporadic schwannomas that were investigated as controls. Two patients died of unrelated causes at 3.2 and 9.9 years, respectively, of follow up. Magnetic resonance images of the head and spine were obtained in seven patients at the end of the follow-up period. New spinal schwannomas were detected in one patient and a residual schwannoma in three. No germline mutations of the NF2 gene were found in these seven patients. Two additional patients originally included in the schwannomatosis group who were 8.6 and 11.7 years old at initial surgery had NF2. One was diagnosed at follow-up review and the other developed a fulminant disease that led to death in 4 years.

CONCLUSIONS

The clinical course, long-term outcome, and genetic mechanism of schwannomatosis differ from that of NF2.

Video thoracoscopic excision of an intercostal neurilemoma presenting as a lateral chest wall tumor

Thoracoscopic surgery has expanded with advances in endoscopic surgical instrumentation. We report on a 21-year-old woman with a complete thoracoscopic resection of an intercostal neurilemoma, which occurred extrapleurally in the ninth intercostal space of the lateral thoracic wall. The tumor was 70 x 40 x 25 mm in size, but a thoracotomy with a rib resection was avoided. The patient had an uncomplicated postoperative course and was discharged on the fourth postoperative day. Thoracoscopic resection of an intercostal neurilemoma, presenting as a lateral chest wall tumor, may be a safe and useful approach with an improved cosmetic result.

Vagal schwannoma

A patient with a benign encapsulated intrathoracic vagal schwannoma is presented and the literature is reviewed. The right paratracheal tumor was identified incidentally on a chest film and excised using a right thoracotomy. Although rare, vagal schwannomas should be considered for any mediastinal mass along the vagus nerves especially when the paratracheal tumor produces minimal or no respiratory symptoms suggesting a slow-growing, encapsulated process.