Neurilemmoma of the Seminal Vesicle: An Unexpected Rare Case During the Treatment of Liver Abscess

By Mingyang He, Junzi Liu, Qiyu Liu

Affiliations

1. Department of Radiology, The Affiliated Hospital of Southwest Medical University, Luzhou, China

doi: 10.29271/jcpsp.2025.06.811

Sir,

Neurilemmomas, also known as schwannomas, are tumours originating from embryonic neural crest-derived Schwann cells.¹ Neurilemmomas are commonly seen in the head, neck, posterior mediastinum, and retroperitoneum.² Seminal vesicle neurilemmomas are extremely rare, with less than 20 cases reported in the literature from 2002 to 2024. Herein, the authors report a case of asymptomatic seminal vesicle neurilemmoma discovered incidentally.

Figure 1: (A) Enhanced abdominal CT in 2019. (B) Enhanced abdominal CT in 2022. (C, D) Enhanced pelvic MRI in 2019. (E, F) Histopathology and immunohistochemistry.

A 79-year-old man, who came to the hospital in May 2019 with chills and fever, underwent a complete blood analysis and enhanced abdominal computed tomography (CT) that sug-gested a large abscess in the left lobe of the liver. Klebsiella pneumoniae liver abscess was definitively diagnosed through ultrasound-guided puncture. Interestingly, the enhanced abdominal CT also indicated a nodular thickening of the patient’s left seminal vesicle (Figure 1A). Further magnetic resonance imaging (MRI) suggested a cystic and solid soft tissue nodule without compression of surrounding tissues (Figure 1C, D). Additionally, neuron-specific enolase (NSE) levels were elevated at 42.34 ng/mL (reference range: 0-16.5 ng/mL). Ultrasound- guided biopsy was performed to determine the nature of the nodule. Haematoxylin-eosin staining showed spindle-shaped tumour cells arranged in lines. Immunohistochemical results displayed diffuse S-100 positivity in tumour cells, with CD34 and Vimentin also being positive, while pan-CK, EMA, CD45, SMA, and Desmin were negative. The Ki-67 proliferation indices were 2% (Figure 1E, F). Based on these findings, a diagnosis of seminal vesicle neurilemmoma was confirmed. As the patient had no significant urinary symptoms, surgical removal of the tumour was not chosen. In November 2022, the patient underwent a repeat enhanced abdominal CT which showed no significant change in the size of the left seminal vesicle mass (Figure 1B). After the multidisciplinary consultation, the patient was advised to opt for conservative treatment.

Most seminal vesicle neurilemmomas are asymptomatic or may present non-specific clinical manifestations such as pain, urinary irritation, and haematospermia when compressing surrounding tissues.³ Therefore, preoperative diagnosis of early asymptomatic cases is challenging. Imaging examinations (ultrasound, CT, MRI, etc.) can detect potential asymptomatic tumours and assess their location, size, and relationship with surrounding tissues, assisting clinicians in designing treatment plans. In addition, the primary task in the diagnostic evaluation of seminal vesicle neurilemmomas is to rule out primary or secondary malignant tumours, as primary malignant lesions of the seminal vesicles are more common than benign lesions.⁴ Thus, histopathological and immunohistochemical examinations are crucial for diagnosis. The tumours are characterised by alternating hypo- and hypercellular areas and mucoid matrix on histology.³ Immunohistochemical staining usually shows diffuse S-100 positivity, while epithelial markers, CD34, and smooth muscle actin are negative.³ Currently, there are no standardised guidelines for the treatment of seminal vesicle tumours. The primary treatment method reported in most cases is still surgical removal. Traditional open surgery has many shortcomings, such as large trauma, long recovery period, and the risk of peripheral organ damage.³ Robotic-assisted removal has the advantages of reduced surgical risk, less damage, and faster recovery, but this method still has the potential risk of incomplete removal.¹ In this case, the option of conservative treatment was explored. For patients with no symptoms, no significant changes in tumour size during follow-up, and those who cannot tolerate surgery, conservative treatment is a viable option.

PATIENT’S   CONSENT:
Informed consent was obtained from the patient to publish this case.

COMPETING   INTEREST:
The authors declared no conflict of interest.

AUTHORS’   CONTRIBUTION:
MH: Drafted, revised, and edited the manuscript.
JL: Performed data collection, analysis, and interpretation.
QL: Performed data collection.
All authors approved the final version of the manuscript to be published.

REFERENCES

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2. Zhang Y, Zhao J, Xu P, Qi Q. Multiple schwannoma of the seminal vesicle: A case report. Medicine 2020; 99(33): e21603. doi: 10.1097/MD.0000000000021603.
3. Lin C, Liang A, Liang S, Wang X, Meng L, Chen M. Laparoscopic surgery combined with the double-J tube implantation for the rare cystic-solid schwannoma of seminal vesicle: A Case Report and Literature Review. Medicine 2022; 101(28):e29352. doi: 10.1097/MD.000 0000000029352.
4. Campi R, Tuccio A, Siena G, Mari A, Vittori G, Lanciotti M, et al. Current strategies for diagnosis and treatment of benign tumors of seminal vesicles: A systematic review of the literature. Anticancer Res 2015; 35(6):3687-91.