骨盆叢狀神經纖維瘤：罕見病例報告

梁柏崧 黃勝賢

彰化基督教醫院外科部泌尿外科

Pelvic Plexiform Neurofibroma: A Rare Case Report

Po-Sung Liang, Sheng-Hsien Huang

Division of Urology, Department of Surgery, Changhua Christian Hospital

Introduction:

Neurofibromas are benign neoplasms originating from Schwann cells, perineurial cells, and fibroblasts, typically categorized as localized, diffuse, or plexiform. Plexiform neurofibroma (PN) is predominantly linked to NF1, where it is frequently regarded as pathognomonic. The occurrence in people lacking NF1 is infrequent, and retroperitoneal involvement is especially atypical.

Despite being histologically benign, PN's clinical manifestation may be complicated by its location, mass effect, or interaction with neighboring structures. The pelvic cavity is an atypical location, and lesions in this area may be misidentified as adnexal tumors, mesenteric cysts, or other retroperitoneal neoplasms. Management is predominantly surgical; nevertheless, total excision might be technically challenging due to the closeness to essential pelvic organs.

We present a sporadic retroperitoneal PN in a woman devoid of NF1, originally identified incidentally but subsequently worsened by obstructive uropathy and urinary bladder bladder involvement, necessitating intricate reconstructive surgery.

Case presentation:

A 68-year-old woman, lacking a family history or cutaneous manifestations of NF1, appeared with a 1-month history of abdominal distension initially. A regular health examination revealed a right hypoechoic lesion measuring 6.05 × 2.05 cm, characterized by internal echoes and septations, via pelvic ultrasonography. Pelvic computed tomography (CT) revealed numerous cystic lesions in the right adnexal area exhibiting modest internal enhancement. Serum tumor markers were within normal limits (CEA 1.9 ng/mL, CA125 5.2 U/mL). Laparoscopic pelvic tumor excision was conducted. During the operation, bladder perforation was noted during dissecting the tumor and was repaired by cystorrhaphy. Histopathology validated the diagnosis of PN, with positive immunohistochemical markers for S-100 and CD34, while being negative for EMA.

The patient was kept under outpatient follow-up. However, serial CT imaging revealed progressive expansion of a lobulated cystic pelvic tumor. The follow-up MRI revealed lobulated cystic masses exhibiting delayed contrast enhancement, consistent with PN. Laparoscopic excision was performed again for tumor recurrence. 2 months later, she manifested right hydronephrosis. Diagnostic ureteroscopy revealed a significant distal ureteral stricture, obstructing the passage of the scope and guidewire, necessitating the placement of a percutaneous nephrostomy. A follow-up CT scan revealed a 2.2 cm spherical mass located at the right upper region of the urinary bladder. Then, definitive surgery was conducted with excision of the recurrent pelvic tumor, partial cystectomy, segmental resection of the right ureter, and ureteroneocystostomy with psoas hitch. Pathology once more verified PN with infiltration into the bladder muscularis propria. Postoperatively, renal function was maintained, hydronephrosis was alleviated, and no urine leakage was observed.

Conclusions:

Sporadic pelvic plexiform neurofibroma absent of NF1 is quite uncommon. Diagnosis necessitates histopathological examination, as imaging lacks specificity. Despite being benign, recurrence and local invasion are prevalent, requiring diligent monitoring. Surgical excision is the primary approach for definite treatment, ensuring oncologic control while maintaining organ function.