Extent of resection of epidermoid tumors and risk of recurrence: case report and meta-analysis

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Intracranial epidermoid tumors are slow-growing, histologically benign tumors of epithelial cellular origin that can be symptomatic because of their size and mass effect. Neurosurgical resection, while the treatment of choice, can be quite challenging due to locations where these lesions commonly occur and their association with critical neurovascular structures. As such, subtotal resection (STR) rather than gross-total resection (GTR) can often be performed, rendering residual and recurrent tumor potentially problematic. The authors present a case of a 28-year-old man who underwent STR followed by aggressive repeat resection for regrowth, and they report the results of the largest meta-analysis to date of epidermoid tumors to compare recurrence rates for STR and GTR.


The authors conducted a systemic review of PubMed, Web of Science, and the Cochrane Collaboration following the PRISMA guidelines. They then conducted a proportional meta-analysis to compare the pooled recurrence rates between STR and GTR in the included studies. The authors developed fixed- and mixed-effect models to estimate the pooled proportions of recurrence among patients undergoing STR or GTR. They also investigated the relationship between recurrence rate and follow-up time in the previous studies using linear regression and natural cubic spline models.


Overall, 27 studies with 691 patients met the inclusion criteria; of these, 293 (42%) underwent STR and 398 (58%) received GTR. The average recurrence rate for all procedures was 11%. The proportional meta-analysis showed that the pooled recurrence rate after STR (21%) was 7 times greater than the rate after GTR (3%). The average recurrence rate for studies with longer follow-up durations (≥ 4.4 years) (17.4%) was significantly higher than the average recurrence rate for studies with shorter follow-up durations (< 4.4 years) (5.7%). The cutoff point of 4.4 years was selected based on the significant relationship between the recurrence rate of both STR and GTR and follow-up durations in the included studies (p = 0.008).


STR is associated with a significantly higher rate of epidermoid tumor recurrence compared to GTR. Attempts at GTR should be made during the initial surgery with efforts to optimize success. Surgical expertise, as well as the use of adjuncts, such as intraoperative MRI and neuromonitoring, may increase the likelihood of completing a safe GTR and decreasing the long-term risk of recurrence. The most common surgical complications were transient cranial nerve palsies, occurring equally in STR and GTR cases when reported. In all postoperative epidermoid tumor cases, but particularly following STR, close follow-up with serial MRI, even years after surgery, is recommended.

ABBREVIATIONS CN = cranial nerve; CPA = cerebellopontine angle; EOR = extent of resection; GTR = gross-total resection; MCA = middle cerebral artery; NTR = near-total resection; PCA = posterior cerebral artery; STR = subtotal resection.

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  • Supplemental Table 1 and Figs. S1–S3 (PDF 1.02 MB)

Article Information

Correspondence Jennifer Moliterno: Yale School of Medicine, New Haven, CT. jennifer.moliternogunel@yale.edu.

INCLUDE WHEN CITING Published online July 5, 2019; DOI: 10.3171/2019.4.JNS19598.

Disclosures The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper.

© AANS, except where prohibited by US copyright law.



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    MR images of an epidermoid tumor in the right ambient cistern. A: Initial presentation in 2010. B: Appearance in 2011 after cystoperitoneal shunt (white arrow) placement in 2010. C: Images after STR in 2013. D: Growth of the epidermoid tumor is seen in 2017. E: Imaging appearance after a NTR in 2018. MRI sequences in A from left to right: diffusion-weighted image, apparent diffusion coefficient map, FLAIR image, and a T1-weighted image after gadolinium administration. The rest of the images in B–E are from diffusion-weighted imaging sequences.

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    Photomicrograph showing the epidermoid cyst lined with maturing and keratinizing squamous epithelium. An area with degenerating cells is present (right side). H & E, original magnification ×10. Figure is available in color online only.

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    Forest plots and pooled recurrence rates for STR (left) and GTR (right) in the main analysis (n = 27 studies).

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    Comparison of the pooled recurrence rates between STR and GTR in the main analysis (n = 27 studies).

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    Comparison of the pooled recurrence rates between STR and GTR in the sensitivity analysis restricted to the studies with longer follow-up durations (≥ 4.4 years) (n = 13 studies).

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    Recurrence rate of all procedures and follow-up times in the studies included in the proportional meta-analysis. The blue line and gray area indicate the natural cubic spline model fitted line and the 95% CI; dotted line demarcates the cutoff point of 4.4 years. Figure is available in color online only.




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