Testicular epidermoid cysts: a reevaluation

Petra Anheuser,E. Stolle,D. Höflmayer,K. P. Dieckmann,S. Mühlstädt,F. Büscheck,G. Lock,J. Kranz

doi:10.1186/s12894-019-0477-1

Abstract

BackgroundTesticular epidermoid cysts (TECs) are rare benign testicular neoplasms. As TECs are rarely associated with germ cell tumours (GCTs), the understanding of biological behaviour and clinical management of TEC is unresolved.MethodsWe retrospectively searched the files of patients treated for testicular neoplasms and germ cell cancer in the time from 2000 to 2017. Those with TEC were subjected to closer review looking to clinical and histological features, and to results from imaging with ultrasonography (US), contrast enhanced sonography (CEUS) and magnetic resonance imaging (MRI).ResultsAmong 589 patients undergoing surgery for testicular tumour, nine simple TECs were identified (1.5, 95% confidence intervals 0.53–2.50%). Median age was 26 years. Imaging revealed sharply demarcated roundish lesions with avascular central areas. Eight patients underwent testis-sparing excision with no recurrence ensuing. One had orchiectomy because of large size of the mass. Histologically, TECs consisted of cornifying squamous cell epithelium and no accompanying germ cell neoplasia in situ. Two additional cases (0.3% of all) required orchiectomy because these TECs were associated with ipsilateral GCT.ConclusionsTEC is usually a benign lesion that can safely be diagnosed with US, CEUS and MRI due to its roundish shape and its avascular centre. Histologically, this TEC corresponds to the prepubertal-type teratoma unrelated to germ cell neoplasia in situ of the 2016 WHO classification. The other subtype of TEC that is associated with invasive GCT represents a teratoma of postpubertal-type. From a clinical point of view it could be easier to differentiate between a “simple TEC” which is benign (prepubertal type) and a “complex TEC” which is malignant because of its association with invasive GCT.

Highlights

Testicular epidermoid cysts (TECs) are rare benign testicular neoplasms
TECs have been documented as part of invasive testicular germ cell tumours (GCTs). it has been hypothesized that two different types of TECs exist, one a truly benign “simple” testicular EC and the other a
The remainder were comprised of extragonadal GCTs as well as relapsing patients or other patients receiving upfront chemotherapy

Summary

Introduction

Testicular epidermoid cysts (TECs) are rare benign testicular neoplasms. As TECs are rarely associated with germ cell tumours (GCTs), the understanding of biological behaviour and clinical management of TEC is unresolved. Testicular epidermoid cysts have been first reported in 1942 [1], but their histogenetic origin has been a matter of dispute ever since. In the recent WHO classification of 2016, testicular epidermoid cysts (TECs) are listed as teratoma of prepubertal type within the group of germ cell tumours unrelated to germ cell neoplasia in situ [2]. TECs have been documented as part of invasive testicular germ cell tumours (GCTs). it has been hypothesized that two different types of TECs exist, one a truly benign “simple” testicular EC and the other a “complex” TEC associated with GCT representing teratoma [4].

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