Spontaneous regression of vestibular schwannomas after resection of contralateral tumor in neurofibromatosis Type 2

Abstract

The authors report on 2 patients with bilateral vestibular schwannomas (VSs) who underwent unilateral surgical tumor removal. One patient was followed up for 4 years, the other for 9; in both cases, the contralateral VS regressed markedly without any additional treatment during the follow-up period. Serial MR imaging was performed to monitor the untreated tumor, which in both cases involved the only hearing ear. The tumors were assessed volumetrically. The contralateral tumors appeared to enlarge mildly at initial follow-up and then, with no treatment, regressed (to 23% of the original maximum volume in Case 1 and to 15% of the original maximum in Case 2). The largest posterior fossa diameter decreased from 30.1 mm to 18.6 mm in Case 1 over 4 years and from 27 mm to 16 mm over 8 years in Case 2. Hearing declined only mildly during follow-up in both patients. These cases demonstrate the first well-documented, long-term, spontaneous VS regressions in patients with neurofibromatosis Type 2. They underline the importance of careful observation of VS involving the only hearing ear in the management of bilateral VS to determine the natural growth pattern of the tumors. The mechanism of the dramatic spontaneous tumor regression is uncertain.

Case of spontaneous regression of carotid body tumor in a SDHD mutant: a discussion on potential mechanisms based on a review of the literature

“…Afterwards, a gradual decrease in tumor size was objectified from 6 months postoperatively. Tumor size increased initially in the second patient as well, whereas a decrease in tumor size was noted from approximately 60 months [23]. A similar mechanism may explain the regression of the left carotid body tumor after initial resection of the carotid body tumor on the right in our case.…”

“…The authors hypothesized that the resected tumor may have been supportive for the existence of the other two. Furthermore, in two patients with neurofibromatosis type 2 and bilateral vestibular schwannomas, spontaneous regression after resection of the contralateral tumor was reported [23]. In this paper, one patient showed an initial increase in tumor size, directly after resection of the contralateral schwannoma.…”

Spontaneous shrinkage of vestibular schwannoma

“…The degree of tumor shrinkage identified ranged between 5.38 and 100% during the same follow-up period. [ 1 2 3 4 7 9 10 11 12 14 15 16 18 19 21 22 24 25 26 27 ]…”

Contemporary management of acoustic neuromas

“…Although no clear pathophysiologic mechanism for such regression is known, this finding emphasizes the importance of careful long‐term radiographic follow‐up for patients with NF2. 48…”

“…27–31 In this environment, the refinement of surgical treatment has moved from a traditional focus of completeness of tumor resection toward a new focus primarily on patient‐centered functional outcomes. 32–49 In this review, we define the important parameters that should be considered in the treatment decisions for vestibular schwannomas.…”