Elsevier

Sexual Medicine Reviews

Volume 8, Issue 4, October 2020, Pages 615-621
Sexual Medicine Reviews

Review
Clinicopathological Presentation and Management of Penile Schwannoma

https://doi.org/10.1016/j.sxmr.2019.12.001Get rights and content

Abstract

Introduction

Patients with penile schwannoma are rare and usually with variant presentations. No evidence-based clinical guideline exists for diagnosis or treatment. To put schwannoma into differential diagnoses of benign soft tissue lesions in the penis is important.

Aim

To analyze and categorize clinical, histopathological, and radiological presentations and apply possible explanation on several fields of penile schwannoma.

Methods

We collected the English literature through the PubMed database of the National Library of Medicine up to October 2019. A newly diagnosed case in Chang Gung Memorial Hospital, Taiwan, was also included. This study categorized lesion locations into the penile body or shaft, glans, or penile root, dorsal or ventral.

Main Outcome Measure

The main outcome measure was to demonstrate clinical, pathological, ultrasonography, and MRI manifestations of penile schwannoma and perform immunohistochemistry staining that has not been performed among penile schwannomas.

Results

We collected 40 cases. Data were arranged in tables. Clear descriptions were added on several fields of penile schwannoma in detail in Discussion.

Conclusion

Penile schwannomas are mostly located at the penile shaft and dorsum of the penis. Dyspareunia is the most reported complaint for sexual dysfunction. This study is the first study in the world to document the expressions of calretinin, SOX10, glial fibrillary acid protein, D2-40 (podoplanin), and cytokeratin AE1/AE3 in penile schwannoma and claims magnetic resonance imaging and pathologic presentations of penile schwannomas are synonymous with schwannomas from head to toe. The current patient may be the first to present with penile schwannoma with schwannomatosis.

Huang LC, Wang HZ, Chu YC, et al. Clinicopathological Presentation and Management of Penile Schwannoma. Sex Med Rev 2020;8:615–621.

Introduction

Schwannomas (also called neurilemomas) are encapsulated tumors made entirely of benign neoplastic Schwann cells that can occur throughout the peripheral nervous system and lead to various clinical outcomes depending on the location. The tumors are sporadically associated with genetic syndromes such as schwannomatosis or neurofibromatosis or may be the result of therapeutic irradiation.1 Schwannomas have a low annual incidence of 0.6 per 100,000 people, and the vast majority were found on the flexor surfaces of limbs.2 Schwannomatosis is the third major form of neurofibromatosis, clinically and genetically distinct from neurofibromatosis 1 (NF1) and NF2. It is characterized by multiple noncutaneous schwannomas in the absence of bilateral vestibular schwannomas and is diagnosed with criteria.3 Management of schwannomas includes pharmacological treatment, surgical resection, and radiosurgery.

Penile schwannomas are extremely rare. We reviewed 36 English-language literature and found 39 cases of them. We are adding a new case of patient with penile root schwannoma, and this case may be the first penile schwannoma with schwannomatosis.

A 56-year-old male patient had been found to have a perineal nodule since the age of 35 years. Recently, he had experienced mild dysuria and tingling over the perineum during urination. He did not have dyspareunia, painful ejaculation, erectile dysfunction, or abnormal penile curvature during erection. The finding of physical examination showed a tender mass of about 5 cm in diameter located at the ventral penile root. Blood and urine chemistry findings were unremarkable.

The finding of magnetic resonance urography (MRU) showed a 5.3 × 2.9 × 2.5 cm wide extent heterogeneous mass at the base of the penis and a high signal intensity of diffusion-weighted image, involving a part of the right penile bulb and the right corpus cavernosum with extension to the perineal area (Figure 1). This mass also displaced the corpus spongiosum to the left. He also had another 3 small enhancing lesions on the dorsum of the penis, and a small right epididymal cyst was also noted on the magnetic resonance urography image. Percutaneous needle biopsy of the penile root mass showed a tumor consisting of bundles of spindle cells with wavy nuclei, scattered degenerated atypia, Verocay bodies, focal loose edematous areas, focal hemosiderin deposition, and focal hyalinized vessels. Tumor cells were diffusely and strongly positive for S-100 protein and negative for CD117 or smooth muscle actin. He was subsequently diagnosed with penile root schwannoma.

Penile-preserving excision was performed on the penile root tumor. A well-encapsulated tumor arising from the corpus cavernosum was carefully dissected free from the penile shaft (Figure 2). The eventual pathology confirmed the diagnosis of penile schwannoma (Figure 3). Other immunohistochemistry (IHC) stains were found to be positive for calretinin and SOX10 and negative for glial fibrillary acid protein (GFAP), cytokeratin AE1/AE3, and D2-40 (podoplanin) (Figure 4).

The lesions on the dorsum of the penis were barely palpable along the penis shaft and could not be found by an intraoperative ultrasound study. After discussing with the patient, we decided not to approach the asymptomatic tumors.

3 weeks later, the patient went to a dermatologist for a 1.2 × 1.0 cm brown plaque on the nape, and the specimen of excisional biopsy showed neurofibroma. He also went to an otolaryngologist for sensorineural hearing loss, headache, and tinnitus and had a follow-up for about half a year. There was no vestibular schwannoma, café-au-lait macules, axillary or inguinal freckles, optic glioma, Lisch nodules, bony lesion, meningioma, or first-degree relatives with NF1 or NF2.

Section snippets

Methods

The images, pathology, and medical records of this case were reviewed with the approval of the Institutional Review Board of the Chang Gung Medical Foundation (protocol number: 201900599B0, date of approval: 2019/04/26) with the need of receiving an informed consent signed by the patient.

We collected the English literature through the PubMed database of the National Library of Medicine up to October 2019. The titles and abstracts were screened for possible inclusion. This study excluded

Results

We collected 40 cases of penile schwannomas, including our patient. The United States had the largest number of cases (8 cases), followed by Taiwan (7 cases). In this study, we categorized lesion locations into the penile body or shaft, glans or penile root, dorsum or ventrum. Cases without full-text access or with limited descriptions or images were not categorized or analyzed in certain items, and the analyzed amount differed depending on criteria of each item. We could only analyze a maximum

Penile Schwannoma With Schwannomatosis

Although there is lack of pathological evidence of dorsal-penile lesions, their magnetic resonance imaging (MRI) presentation was similar to that of the penile base. Neurofibromas and schwannomas could both show a low signal intensity on T1-weighted images and high signal intensity on T2-weighted images.4,5 The patient may have either sporadic schwannoma and neurofibroma or schwannomatosis. In other words, if the dorsal-penile lesions are schwannomas, he is the first case of penile schwannoma

Conclusion

Penile schwannoma is extremely rare and mostly located at the penile shaft and the dorsum of the penis. Dyspareunia is the most complained symptom for sexual dysfunction. We reported the first case of penile root schwannoma in Taiwan. This study is the first study documenting the expressions of calretinin, SOX10, GFAP, D2-40 (podoplanin), and cytokeratin AE1/AE3 in penile schwannoma and claims MRI and pathologic presentations of penile schwannomas are synonymous with schwannomas from head to

Statement of authorship

Category 1

  1. (a)

    Conception and Design

    • Liang-Chen Huang; Cheng-Keng Chuang

  2. (b)

    Acquisition of Data

    • Liang-Chen Huang; Hong-Zhen Wang; Yuan-Cheng Chu; Kwai-Fong Ng; Cheng-Keng Chuang

  3. (c)

    Analysis and Interpretation of Data

    • Liang-Chen Huang; Kwai-Fong Ng; Cheng-Keng Chuang

Category 2
  1. (a)

    Drafting the Article

    • Liang-Chen Huang; Cheng-Keng Chuang

  2. (b)

    Revising It for Intellectual Content

    • Liang-Chen Huang; Hong-Zhen Wang; Yuan-Cheng Chu; Kwai-Fong Ng; Cheng-Keng Chuang

Category 3
  1. (a)

    Final Approval of the Completed Article

    • Liang-Chen Huang; Hong-Zhen Wang; Yuan-Cheng

Acknowledgments

The authors wish to thank Professor Winston W. Shen and MD. Ya-Hui Wang at Taipei Municipal Wan Fang Hospital and May Lu for assistance in editing this manuscript and acknowledge the support of the Maintenance Project of the Center for Big Data Analytics and Statistics (Grant CLRPG3D0044) at the Chang Gung Memorial Hospital.

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  • Cited by (0)

    Funding: None.

    Conflicts of Interest: The authors declare no conflicts of interest.

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