Endoscopic ultrasound-guided fine-needle aspiration for the diagnosis of retroperitoneal schwannoma

Clinical characteristics and prognosis of cystic degeneration in retroperitoneal schwannoma: A retrospective study of 79 patients

BACKGROUND AND PURPOSE

Diagnosis of retroperitoneal schwannoma (RS), especially cystic RS, is frequently missed or delayed owing to its rarity, location, nonspecific symptoms, and similarities with other tumors on various imaging modalities. This study aimed to determine associations between clinical, radiological, and histopathologic features and outcome.

MATERIALS AND METHODS

Seventy-nine patients with pathologically confirmed RS who underwent tumor resection between June 2010 and June 2020 were retrospectively reviewed and analyzed. Patients were stratified into three groups according to degree of tumoral cystic degeneration.

RESULTS

Cystic degeneration was significantly associated with multiple foci (p = 0.025), calcification (p = 0.012), and hemorrhage (p = 0.000), but not size (p = 0.08), high Ki-67 (p = 0.094), malignancy (p = 0.115; prevalence of cystic degeneration in the benign and malignant groups were 53.9% vs 100%), rough margin (p = 0.162), or irregular shape (p = 0.369). Malignant RS was significantly associated with multiple lymph nodes enlargement (p = 0.034). Tumor size, margins, shape, or/and multiplicity did not significantly differ between benign and malignant tumors. No recurrence occurred in patients with benign RS (mean follow-up, 45 months). All malignant tumors recurred; mean time to recurrence was 11.4 months (mean follow-up, 33 months).

CONCLUSION

Since RS is misdiagnosed mostly as malignancy and diagnosis is often delayed, a suspicion is necessary for diagnosis when atypical features are present. In RS, cystic degeneration was not associated with tumor size, Ki-67, or malignancy; however, it was significantly associated with multiple foci, calcification, and hemorrhage. Cystic degeneration and related factors are useful for the diagnosis of RS. Malignant RS should be considered when a mass involves multiple lymph nodes. Margins, morphology, and size are not associated with malignancy. Pathological tumor type, tumor location, and adjacent anatomic structures are associated with outcome.

Preoperative management of giant retroperitoneal schwannoma: A case report and review of the literature

Schwannomas rarely occur in the retroperitoneum, and are normally not aggressive. Preoperative diagnosis is difficult and the surgeon may confront blood vessels, nerves or organs damage, since the intra-operative findings are various. The diagnosis and treatment of malignant schwannomas in the retroperitoneum are even more challenging. In addition, the prognosis of malignant schwannomas is extremely poor. The present study reports the case of a 52-year-old woman who presented with a 6-month history of an abdominal mass in the left lower quadrant. The local doctor determined a preliminary diagnosis of abdominal giant tumor and referred the patient to the First Affiliated Hospital, Medical School of Xi'an Jiaotong University, (Xi'an, China). Following discussion, the patient underwent a surgical resection. Low-grade malignant schwannoma was diagnosed following histological examination. No evidence of recurrence or any other complication was observed at the 18-month follow-up examination. The present study reports a case of giant retroperitoneal schwannoma (RS), and includes a literature review in order to provide an overview of the diagnosis, treatment and prognosis of RS and discuss preoperative management strategies for the disease.

Laparoscopic resection of a retroperitoneal pelvic schwannoma

Schwannomas are rarely located in the pelvis. A 54-year-old woman was found incidentally to have a tumor in the abdomen. Abdominal computed tomography and magnetic resonance imaging revealed a well-defined, heterogeneous tumor, 5 cm in diameter, in the pelvic cavity. With a diagnosis of a mesenteric tumor, a laparoscopic procedure was performed. Intra-operatively, an elastic tumor was identified in the pelvis adjacent to the right internal iliac vein and ureter. The tumor was dissected free from adjacent structures using Liga-Sure and blunt maneuvers. A complete laparoscopic excision was performed. Histopathological examination revealed a benign schwannoma. The patient had an uneventful post-operative course, and was discharged on the fourth post-operative day. Laparoscopic treatment is useful and feasible for retroperitoneal pelvic schwannoma, with minimal invasiveness and an early post-operative recovery. Thus, this procedure may be the first-choice surgical procedure for retroperitoneal pelvic schwannomas.

Incidental diagnosis of a retroperitoneal schwannoma in a patient with chronic leukemia undergoing prostatic biopsy

We present a case of retroperitoneal schwannoma incidentally diagnosed in a patient undergoing surgical drainage of a pelvic abscess as a complication of a prostatic biopsy. A 50-year-old male, suffering from lymphatic leukemia, came to our observation due to lichen ruber planus and ejaculatory pain. The patient underwent a trans-perineal ultrasound-guided biopsy of the right seminal vesicle and of a hypoechoic area documented by ultrasonography. 48 hours after the procedure, the patient had developed: cold sores, shortness of breath with dyspnea, and high fever (40°C). The patient was hospitalized, underwent an emergency CT which documented a right presacral and pararectal liquid mass (abscess). The patient underwent emergency laparotomy and drainage of the abscess. The lesion histological examination revealed a retroperitoneal schwannoma with inflammatory phenomena and hyperplasic lymphadenitis. The retroperitoneal schwannoma is a silent disease whose only clinical manifestation coincides with the compression of adjacent anatomical structures. In many cases, the symptoms, even if present, as in this case (ejaculatory pain with compression of the seminal vesicle), are non-specific, thus delaying diagnosis and the therapeutic approach.

Three cases of retroperitoneal schwannoma diagnosed by EUS-FNA

Schwannomas are peripheral nerve tumors that are typically solitary and benign. Their diagnosis is largely based on surgically resected specimens. Recently, a number of case reports have indicated that retroperitoneal schwannomas could be diagnosed with endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA). We report the diagnosis of three cases of schwannoma using EUS-FNA. Subjects were two males and one female, ages 22, 40, and 46 years, respectively, all of whom were symptom-free. Imaging findings showed well-circumscribed round tumors. However, as the tumors could not be diagnosed using these findings alone, EUS-FNA was performed. Hematoxylin-eosin staining of the resulting tissue fragments revealed bland spindle cells with nuclear palisading. There was no disparity in nuclear sizes. Immunostaining revealed S-100 protein positivity and all cases were diagnosed as schwannomas. Ki-67 indexes were 3%-15%, 2%-3%, and 3%, respectively. No case showed any signs of malignancy. As most schwannomas are benign tumors and seldom become malignant, we observed these patients without therapy. All tumors demonstrated no enlargement and no change in characteristics. Schwannomas are almost always benign and can be observed following diagnosis by EUS-FNA.