Penile schwannoma: sonographic features

Penile schwannoma mistaken for hemangioma: a rare case report and literature review

Penile neoplasm is uncommon. Schwannomas of the penis are especially rare. For this reason, it is difficult to get an accurate impression to enable decision making. This report primarily deals with the mistaken diagnosis of hemangioma, to the surgery, and the follow-up in real-world. A 38-year-old male patient presented with a palpable mass in the penile root that increased in size with erection. One year after the mass had been found, the patient visited the hospital and complained that the mass was growing. Moreover, the patient explained that the mass seemed to increase during penile erection. On physical examinations, a 2 cm mass without tenderness was palpated in the left penoscrotal junction. About 2.1 cm in size, an isoechoic mass was observed next to the corpus cavernosum on ultrasonography. There was high vascularity inside of the mass. Excision and biopsy were decided upon. Following surgery, a schwannoma was confirmed by pathology. After three months, the patient did not complain of any symptoms and had normal erectile function. Most of these tumors are benign. By December 2020, 40 cases were reported, of which 6 were diagnosed as malignant. The most frequent occurrence site is the penile shaft. In all cases, surgical resection was performed and no recurrence was found. The aim of this case report is to assist clinicians in choosing the best treatment option when faced with this rare condition by discussing the radiological, pathological, and clinical course.

Clinicopathological Presentation and Management of Penile Schwannoma

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.

Clinical Features and Treatment of Penile Schwannoma: A Systematic Review

Schwannomas, although common in the head and limbs, are an exceedingly rare tumor of the penis. We conducted a systematic review to include 33 patients with schwannoma of the penile shaft or glans penis. Most patients presented with a single painless nodule on the dorsal aspect of the penile shaft. These nodules were slow growing, with an average of 62 months from the onset to presentation. Several cases were accompanied by sexual dysfunction. Most histologic studies were consistent, with a benign schwannoma that showed a palisading Antoni A and Antoni B pattern without malignant changes in cell morphology. Of the 14 studies in which a history of genetic disease was investigated, only 2 reported a connection to neurofibromatosis. These tumors were treated with surgical excision, and 4 malignant cases received additional chemotherapy or radiotherapy. All the patients had achieved full remission by the final follow-up examination. Given the rarity of this tumor, the present review of available case studies serves to comprehensively describe the clinical presentation and treatment approaches to penile schwannoma.