Peripheral nerve sheath tumors. Benign or malignant? The role of MRI and ultrasonography in a case report

Predicting the Risk of Postoperative Complications of Schwannoma Surgery: Development and Assessment of a New Predictive Nomogram

BACKGROUND

 The aim of this study was to develop and internally validate a risk nomogram for postoperative complications of schwannoma surgery.

METHODS

 From 2016 to 2020, we reviewed 83 patients who underwent schwannoma resection with a total number of 85 schwannomas. A predictive model was developed based on the dataset of this group. During model construction, univariate and multivariate logistic regression analysis were used to determine the independent predictors of postoperative complications. Assessment of the discriminative function, calibrating proficiency, and clinical usefulness of the predicting model was performed using C-index, calibration plot, receiver operating characteristic (ROC) curve, and decision curve analysis. Internal validation was assessed using bootstrapping validation.

RESULTS

 Predictors contained in the prediction nomogram included age, tumor location, symptoms, and surgical approach. The model displayed satisfying abilities of discrimination and calibration, with a C-index of 0.901 (95% confidence [CI]: 0.837-0.965). A high C-index value of 0.853 was achieved in the interval verification. Decision curve analysis showed that the nomogram was clinically useful when intervention was decided at the complication possibility threshold of 2%.

CONCLUSION

 This new risk nomogram for postoperative complications of schwannoma surgery has taken age, tumor location, symptoms, and surgical approach into account. It has reasonable predictive accuracy and can be conveniently used. It shall help patients understand the risk of postoperative complications before surgery, and offer guidance to surgeons in deciding on the surgical approach.

Neurofibromatosis type I with malignant peripheral nerve sheath tumors in the upper arm: A case report

RATIONALE

Malignant peripheral nerve sheath tumor occurring in the context of neurofibromatosis type I (NF1) is relatively rare. Herein, we report a case of NF1 with malignant peripheral nerve sheath tumor in the upper arm.

PATIENT CONCERNS

A 24-year-old man presented with a mass in the medial part of the left upper arm that had been present for more than 20 years. In the previous 1 year prior to admission, the mass had grown significantly. Physical examination showed cafe-au-lait spots of variable sizes throughout the body and multiple masses in the medial part of the left upper arm. Three months later after the resection of the masses, the patient was readmitted to our department due to tumor recurrence. Two months after the extended resection, in situ recurrence of the tumor was noted again. Four months after the operation and the administration of radiotherapy, a mass was found in the outside of the left upper arm.

DIAGNOSIS

Immunohistochemical staining showed the masses were positivity for vimentin, CD34, and S100; the tumor cells were negative for PGP9.5, CD57, EMA, and SMA. The Ki-67 labeling index was approximately 40%. A diagnosis of malignant peripheral nerve sheath tumor was made.

INTERVENTIONS

Surgical resection was performed for both the primary tumors and the 2 subsequent recurrence tumors. The patient underwent radiotherapy with 60 Gy in 30 fractions after the third operation. Four months after the administration of radiotherapy, the patient underwent tumorectomy of a mass in the outside of the left upper arm.

OUTCOMES

During the 4-month follow-up after the fourth operation, the patient's condition was stable.

LESSONS

Malignant peripheral nerve sheath tumor in NF1 is an exceedingly rare entity that poses a great diagnostic challenge. High-frequency ultrasound can support the diagnosis.

CT and MRI of superficial solid tumors

Superficial solid masses are common conditions in clinical practice, however, some of which can be easily diagnosed and others would be difficult. Although imaging of superficial masses is not always characteristic, it would be helpful to give a definitive diagnosis or narrow a differential diagnosis. Crossing-section imaging can depicture the masses directly, find some pathognomonic signs and demonstrate their relationship with adjacent structures, which can provide decision support for clinician's reference. Computed tomography (CT) can be used to detect calcifications and bone erosion which could not be seen on radiographs. Magnetic resonance imaging (MRI) is the preferred way for evaluating soft tissue lesions and provides information on hemorrhage, necrosis, edema, cystic and myxoid degeneration, and fibrosis. Other advantages of MRI are its superior soft tissue resolution and any profile imaging, which can aid the assessment of extension and adjacent infiltration. Positron emission tomography (PET)/CT and PET/MRI have been increasingly used in bone and soft tissue sarcomas and provides advantages in the initial tumor staging, tumor grading, therapy assessment, and recurrence detection. Therefore, imaging examination can play an important role in treatment decision making for superficial solid tumors. Here we review the important conditions presenting as superficial mass and show the imaging of typical cases diagnosed in our hospital.

Imaging of the malignant peripheral nerve sheath tumour with emphasis οn ultrasonography: correlation with MRI

Malignant peripheral nerve sheath tumours affect 0.001 % of the population. The epithelioid subtype accounts for only 5 % of them. We herein present a patient with a palpable mass on the left calf, which was investigated by ultrasonography, ultrasonographically guided fine-needle biopsy and MRI. Ultrasonography estimated the size of the tumour and evaluated its echotexture. Doppler technique detected characteristic corkscrew-type blood vessel entering in the upper pole of the mass. T1-weighted, fat-suppression and gadolinium-enhanced MRI sequences confirmed ultrasonographic findings. In conclusion, although final diagnosis was established by biopsy, ultrasonography and MRI proved complementary in the characterization of the lesion and planning of surgery.