Malignant peripheral nerve sheath tumors in the setting of segmental neurofibromatosis. Case report

The Risk of Peripheral Nerve Tumor Biopsy in Suspected Benign Etiologies

BACKGROUND

Peripheral nerve sheath tumors (PNSTs) are tumors with unique clinical and imaging features that present to a variety of physicians. These lesions are often referred for biopsy, which can put nerve fascicles at risk. Preoperative biopsy may cause distortion of normal anatomic planes, making definitive resection difficult.

OBJECTIVE

To evaluate the neurological risks of preoperative biopsy in benign PNSTs.

METHODS

Surgical cases collected retrospectively using a prospectively established database of PNSTs treated by a single surgeon between 1997 and 2019. Patients were dichotomized depending on preoperative biopsy. The effects of biopsy were assessed via history and physical examination both pre- and postdefinitive resection.

RESULTS

A total of 151 cases were included. Only 23.2% (35) of patients underwent preoperative biopsy, but 42.9% of these experienced new or worsening neurological examination immediately following biopsy. After definitive resection, the rate of neurological deficit was significantly different between the 2 groups with 60% of biopsy patients and 19% of those patients not biopsied experiencing decline in examination (F = 25.72, P < .001). Odds ratio for any postoperative deficit for biopsy was 6.40 (CI [2.8, 14.55], P < .001). Univariate logistic regression of neurological deficit with patient age, sex, tumor type, and biopsy status showed that only biopsy was associated with the occurrence of any postoperative deficit.

CONCLUSION

Biopsy of benign PNSTs is associated with a high rate of neurological deficit both immediately following the procedure and after definitive resection. Careful selection is imperative prior to proceeding with biopsy of nerve sheath tumors exhibiting benign features given the unacceptably high rate of neurological decline.

Neurofibromatosis 1 French national guidelines based on an extensive literature review since 1966

Neurofibromatosis type 1 is a relatively common genetic disease, with a prevalence ranging between 1/3000 and 1/6000 people worldwide. The disease affects multiple systems with cutaneous, neurologic, and orthopedic as major manifestations which lead to significant morbidity or mortality. Indeed, NF1 patients are at an increased risk of malignancy and have a life expectancy about 10-15 years shorter than the general population. The mainstay of management of NF1 is a patient-centered longitudinal care with age-specific monitoring of clinical manifestations, aiming at the early recognition and symptomatic treatment of complications as they occur. Protocole national de diagnostic et de soins (PNDS) are mandatory French clinical practice guidelines for rare diseases required by the French national plan for rare diseases. Their purpose is to provide health care professionals with guidance regarding the optimal diagnostic and therapeutic management of patients affected with a rare disease; and thus, harmonizing their management nationwide. PNDS are usually developed through a critical literature review and a multidisciplinary expert consensus. The purpose of this article is to present the French guidelines on NF1, making them even more available to the international medical community. We further dwelled on the emerging new evidence that might have therapeutic potential or a strong impact on NF1 management in the coming feature. Given the complexity of the disease, the management of children and adults with NF1 entails the full complement healthcare providers and communication among the various specialties.

Malignant peripheral nerve sheath tumour – A long story: Case report

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Segmental neurofibromatosis with MPNST showing multiple recurrences has not been reported in literature.

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Studies were not conducted regarding the survival rate of such patients due to its extreme low incidence.

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Being considered as a highly aggressive sarcoma, our patient with MPNST survived for a long period without distant metastasis.

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Maintenance of old records helped to carry out review workup effectively.

Introduction

We present a rare case of Malignant Peripheral Nerve Sheath Tumour (MPNST) of the upper limb, which was excised thirteen times in thirteen years and ultimately ended in above elbow amputation.

Presenting complaint and investigations

A 48 year old female presented initially with a localised swelling of 2 cms diameter in the front of the left elbow in 2007, which was excised. It recurred repeatedly and was excised. In the earlier presentations, the swellings were firm, mobile and not fixed to bone. In the last stage alone, bone fixity was identified. All the fourteen surgeries were performed by the primary author from 2007 to 2020, as the patient was particular.

The main clinical diagnoses

had been neurofibroma and fibrosarcoma. There was no evidence of distant metastasis all these years. She did not respond to radiation or chemotherapy. Initially it was single, but later multiple. She had no clinical features of Neurofibromatosis 1 (NF1) or any family history. As the history progressed, the swellings became muscle deep and later encircled the radial nerve. The radial nerve was salvaged on three occasions. On the last three occasions, the tumour had to be shaved off from the humerus. The final amputation specimen showed a single tumour infiltrating the humerus and x-ray revealed bone destruction and tumour calcification. Final diagnosis was aided by immunohistochemistry (IHC) and cytogenetic study (FISH).

Conclusion

The case is presented for the rarity of the presentation and the trust and dependence of the patient on her personal surgeon.

Malignant peripheral nerve-sheath tumors in an adolescent patient with mosaic localized NF1: A case report

Malignant peripheral nerve-sheath tumors (MPNSTs) are rare malignancies that are often observed in patients with neurofibromatosis type 1 (NF1). However, the occurrence of MPNST associated with mosaic localized NF1 is extremely rare. Previous reports have revealed that MPNST was associated with mosaic localized NF1 in only three patients who were >40 years of age. The present report details a 16-year-old man who presented with pain and a 3 cm mass on the medial side of the right knee. Magnetic resonance imaging revealed a circumscribed soft tissue tumor located in the subcutaneous tissue. His previous doctor believed that it was benign and conducted a marginal resection. However, postoperative histology results demonstrated spindle cell sarcoma, following which the patient was referred to The Osaka International Cancer Institute. Localized café-au-lait spots were identified in the affected leg, which inferred that the patient had NF1-related MPNST. A wide resection was performed to completely resect the residual tumor; however, a definitive histological diagnosis was challenging due to the small residual tumor. Hence, the genomic mutations of NF1 in the regional café-au-lait spots were analyzed. The result revealed an NF1 microdeletion and a consistently limited expression of NF1 in the tumor sample. Finally, the patient was diagnosed with MPNST with mosaic localized NF1. Local recurrence and distant metastasis were not observed 1.5 years after surgery. In conclusion, the present report presented MPNST in an adolescent patient with mosaic localized NF1. The occurrence of MPNSTs correlated with mosaic localized NF1 is extremely rare. However, it is of high-grade malignancy and therefore, its clinical features should be considered by orthopedists and pathologists.

Cutaneous and Systemic Findings in Mosaic Neurofibromatosis Type 1

BACKGROUND/OBJECTIVES

Mosaic neurofibromatosis type 1 (MNF1) is a variant of neurofibromatosis type 1 (NF1) in which clinical manifestations are limited to one or several body segments. The objective was to characterize the cutaneous features and associated systemic findings in a cohort of children with MNF1.

METHODS

We performed a retrospective study of 40 children diagnosed with MNF1 at the Department of Dermatology, Hospital Infantil Niño Jesús, Madrid, Spain, from January 1, 1986, to October 31, 2015.

RESULTS

All patients had pigmentary changes, alone (n = 39) or in combination with neurofibromas (n = 1). Twenty-four cases fulfilling the definition of MNF1 had six or more café au lait spots with or without freckling within the affected segment. They all lacked any other National Institutes of Health criteria of NF1. No patient had juvenile xanthogranuloma (JXG) or nevus anemicus (NA). Two children with MNF1 had epilepsy and two others developed malignancy (Hodgkin's lymphoma and ganglioneuroblastoma).

CONCLUSIONS

Pigmentary changes are the most frequent presentation of MNF1 in children. MNF1 must be considered with segmentary distribution of freckling and café au lait spots. Other frequent cutaneous findings in NF1, such as JXG or NA, seem to be exceptional in MNF1. Although the possibility of systemic complications and cancer risk seem to be low, patients must be followed up.

An Update on Neurofibromatosis Type 1: Not Just Café-au-Lait Spots and Freckling. Part II. Other Skin Manifestations Characteristic of NF1. NF1 and Cancer

Neurofibromatosis type 1 (NF1) is the most common neurocutaneous syndrome and probably the one best known to dermatologists. Although the genetic locus of NF1 was identified on chromosome 17 in 1987, diagnosis of the disease is still based primarily on clinical observations. The 7 diagnostic criteria of the National Institutes of Health, which were established in 1988, include 3 skin manifestations (café-au-lait spots, freckling on flexural areas, and cutaneous neurofibromas). The age at which these diagnostic lesions appear is variable: onset can be late in some patients while others never develop certain symptoms. Definitive diagnosis may therefore be delayed by years. Although the appearance of the characteristic café-au-lait spots and freckling in the early years of childhood are very suggestive of the disease, these signs are not pathognomonic and, in isolation, do not constitute sufficient evidence to establish a definitive diagnosis. Thus, other diagnoses should be considered in patients whose only symptoms are café-au-lait spots and freckling. By contrast, the presence of multiple cutaneous neurofibromas or at least 1 plexiform neurofibroma is a very specific indication of NF1. Identification of the different types of neurofibroma allows us to confirm the diagnosis and initiate appropriate management.

Mosaic Neurofibromatosis Type 1: A Systematic Review

Confusion is widespread regarding segmental or mosaic neurofibromatosis type 1 (MNF1). Physicians should use the same terms and be aware of its comorbidities and risks. The objective of the current study was to identify and synthesize data for cases of MNF1 published from 1977 to 2012 to better understand its significance and associations. After a literature search in PubMed, we reviewed all available relevant articles and abstracted and synthetized the relevant clinical data about manifestations, associated findings, family history and genetic testing. We identified 111 articles reporting 320 individuals. Most had pigmentary changes or neurofibromas only. Individuals with pigmentary changes alone were identified at a younger age. Seventy-six percent had localized MNF1 restricted to one segment; the remainder had generalized MNF1. Of 157 case reports, 29% had complications associated with NF1. In one large case series, 6.5% had offspring with complete NF1. The terms "segmental" and "type V" neurofibromatosis should be abandoned, and the correct term, mosaic NF1 (MNF1), should be used. All individuals with suspected MNF1 should have a complete physical examination, genetic testing of blood and skin, counseling, and health surveillance.

Neurofibromatosis type 1 and diabetes mellitus: an unusual association

Neurofibromatosis type 1 is a multisystemic disease. It may manifest as abnormalities of the nervous tissue, bones, soft tissue, or skin. Autoimmune disease associated with NF1 can be seen. Diabetes mellitus is rarely seen in association with NF1. Here, we report a case with established NF1 who also had a diagnosis of diabetes mellitus.

An orthotopic xenograft model of intraneural NF1 MPNST suggests a potential association between steroid hormones and tumor cell proliferation

Malignant peripheral nerve sheath tumors (MPNST) are the most aggressive cancers associated with neurofibromatosis type 1 (NF1). Here we report a practical and reproducible model of intraneural NF1 MPNST, by orthotopic xenograft of an immortal human NF1 tumor-derived Schwann cell line into the sciatic nerves of female scid mice. Intraneural injection of the cell line sNF96.2 consistently produced MPNST-like tumors that were highly cellular and showed extensive intraneural growth. These xenografts had a high proliferative index, were angiogenic, had significant mast cell infiltration and rapidly dominated the host nerve. The histopathology of engrafted intraneural tumors was consistent with that of human NF1 MPNST. Xenograft tumors were readily examined by magnetic resonance imaging, which also was used to assess tumor vascularity. In addition, the intraneural proliferation of sNF96.2 cell tumors was decreased in ovariectomized mice, while replacement of estrogen or progesterone restored tumor cell proliferation. This suggests a potential role for steroid hormones in supporting tumor cell growth of this MPNST cell line in vivo. The controlled orthotopic implantation of sNF96.2 cells provides for the precise initiation of intraneural MPNST-like tumors in a model system suitable for therapeutic interventions, including inhibitors of angiogenesis and further study of steroid hormone effects on tumor cell growth.

Unilateral limb enlargement in a dog with a malignant peripheral nerve sheath tumor

A 3- to 4-month-old female Golden Retriever dog presented with right hind limb enlargement. Physical examination of the limb and radiographic findings initially included soft tissue swelling with elongation, bowing, and cortical irregularity of the femur and tibia. During a period of approximately 7 months, pathology in the limb progressed to include tarsal laxity, muscle atrophy, avulsion of the gastrocnemius muscle, and luxation of the patella. During surgical intervention to shorten the limb and repair the patellar luxation, a large soft tissue cyst was identified along the caudal aspect of the femur and stifle. The limb was later amputated, and a final diagnosis of malignant peripheral nerve sheath (PNS) tumor of the sciatic nerve and surrounding soft tissues was made. The unilateral limb enlargement in this dog appears to have been because of the development and progression of a malignant PNS tumor. The presentation and associated pathologic changes in the limb are unusual for canine PNS tumor but have similarities with neurofibromatosis in the limbs of humans.

Complication avoidance

Complications are relatively common in the evaluation and treatment of patients with peripheral nerve tumors. The complications are frequently avoidable. Physicians and surgeons managing patients with these lesions must possess sufficient knowledge about peripheral nerve tumors and their natural history as well as good diagnostic, decision-making, and technical skills. By avoiding often unnecessary complications, patients and surgeons can be rewarded with better outcomes.

Segmental neurofibromatosis in childhood

Segmental neurofibromatosis refers to individuals who have manifestations of neurofibromatosis type 1 (NF-1) limited to one area of the body. It results from a post-conceptional mutation in the NF-1 gene leading to somatic mosaicism. Although it is generally considered a rare condition, this report of 39 children with segmental NF-1 demonstrates that it is commonly seen in a pediatric NF-1 referral center. The mean age at diagnosis was 7.8 years (range: 2-25 years). Twenty-nine patients had only pigmentary manifestations of segmental NF-1, including seven who had only café-au-lait macules and 22 who had café-au-lait macules and freckling. Two patients had isolated plexiform neurofibromas; a third patient had a plexiform neurofibroma of the eyelid in addition to ipsilateral dysplasia of the sphenoid wing and Lisch nodules. A 12-year-old girl had an isolated tibial pseudarthrosis. An 8-year-old boy had an isolated optic pathway tumor, which behaved both biologically and radiographically as an NF1-associated tumor. While most children with segmental NF-1 have only localized pigmentary changes, some children will have isolated plexiform neurofibromas, pseudarthroses, or optic pathway tumors. Accurate diagnosis of segmental NF-1 is crucial for both management and genetic counseling.

Malignant peripheral nerve sheath tumor of the parotid gland

Malignant peripheral nerve sheath tumor (MPNST) has been defined as any malignant tumor arising from or differentiating toward cells of the peripheral nerve sheath. We treated a case of MPNST arising from the right parotid gland that showed a highly aggressive course. We reviewed the English-language literature published since 1990 and found 142 cases of head and neck MPNST reported within the past 13 years. The results of the review suggested that MPNSTs may arise from any organs of the head and neck. Immunohistochemical analysis of various neural markers plays a significant role in the evaluation of the histologic diagnosis. Curative treatment based on radical resection of MPNSTs of head and neck origin is more difficult than treatment of MPNSTs of other origins.

Segmental neurofibromatosis-induced spinal cord compression. Case report

Spinal segmental neurofibromatosis (NF) is a rare entity. To date, patients in reported cases of segmental NF (or NF5) have harbored neurofibromas involving the peripheral nerves only. The author reports a rare case of segmental NF that caused spinal cord compression in a 40-year-old woman who presented with a 6-month history of intercostal neuralgia. Examination revealed mild lower-extremity weakness and dysesthesia in the right-sided T-9 dermatome. Magnetic resonance imaging revealed three neurofibromas involving the T-9 region, which were excised, and the patient's neuralgic pain was resolved postoperatively. Traditionally, it has been believed that segmental NF involved only the peripheral nerves. The present case illustrates that although rare, spinal cord compression can also occur in patients with segmental NF.