Malignant peripheral nerve sheath tumor of intracranial nerve: a case series review.

OBJECTIVES: The incidence of malignant peripheral nerve sheath tumor (MPNST) is approximately 0.001%. Those involving intracranial nerves are even more exceptional. Little information is available concerning work up and management. Our objective is: (1) to review all cases of intracranial MPNST described in the literature, (2) to highlight the suspicion of intracranial MPNST, (3) to identify the gross pathology, the histopathology, the immunohistochemistry, (4) to discuss the differential diagnosis, the treatment, the recurrence rate, the follow-up, the incidence of metastasis and the prognosis. METHODS: We reviewed English, Spanish and French literature published from 1950 to date. We used the following Keywords: "malignant peripheral nerve sheath tumor", "cranial nerve", "neurosarcoma", "malignant schwannoma", "neurofibroma", "malignant neurofibroma" and "nerve tumor". We considered cases where MPNST involved an intracranial cranial nerve. The results yielded 20 relevant studies, in which 31 patient's records were transcribed. We also added our case to this series. RESULTS: We identified 32 cases of cranial MPNST including our case. The age ranged from 5 to 75 years old with most patients being in the 5th and 6th decade. Male to female ratio is 2.5:1. Most cases are developed sporadically (50%), 31% arise from a malignant transformation of schwannoma and 19% from a neurofibroma. Imaging findings were not specific. The cranial nerve VIII is the most involved (15/32), followed by the Vth (10/32) and the VIIth (5/32). 4 cases had neurofibromatosis type 1 and 2 had neurofibromatosis type 2. MPNST will strongly express protein S-100 and collagen IV-laminin. 13 cases were treated with radiotherapy for tumor recurrence and metastasis. In these cases the survival rate was better than the cases without radiotherapy. Fatal outcome occurred in 66% of patients whereas 19% were reported alive with or without complications. The seven cases reported to have metastasis were entirely to the spine. The mean time of recurrence or metastasis is 12.2 months. CONCLUSION: MPNST of cranial nerves are very rare. In neurofibroma, even though MPNST is mainly associated to type 1, we should keep in mind its association to NF2. Mainstay of treatment is radical resection with adjuvant radiotherapy. Inaccessibility of cranial MPNST may explain the subtotal resection and thus the poor prognosis. Metastasis to the spinal cord is the most frequent one. A close postoperative follow-up is mandatory to eliminate recurrence.

Malignant peripheral nerve sheath tumor of the orbit: malignant transformation from neurofibroma without neurofibromatosis.

A 52-year-old woman suffered from progressive proptosis and vision loss due to a large tumor in her right orbit. Multiple recurrences of the tumor were treated with surgical excision. The pathologic diagnosis in each recurrence was neurofibroma, and the tumor transformed to malignant peripheral nerve sheath tumor in the final pathologic diagnosis. Orbital exenteration and postoperative irradiation were applied and there has been no evidence of tumor recurrence 5 years postoperatively.

Radiotherapy and radiosurgery for benign neurofibromas.

The purpose of this study was to evaluate the efficacy of radiotherapy (RT) and stereotactic radiosurgery (SRS) for neurofibromas. We studied 4 patients treated with RT (3 patients) or SRS (1 patient) and followed from 1.7 to 14.8 years. The tumor remained locally controlled in all patients. No significant complications related to treatment were observed. RT and SRS are likely to locally control neurofibromas in patients who require treatment and are not good candidates for complete resection.

Isolated plexiform neurofibroma: treatment with three-dimensional conformal radiotherapy.

OBJECTIVES: To present a case of an unusual benign tumor of the tongue treated successfully with radiotherapy. STUDY DESIGN: Case report. METHODS: Retrospective chart review. RESULTS: A 60-year-old man presented with a painful submucosal lesion of the tongue base. Computed tomography showed an infiltrative soft-tissue mass involving the left base of the tongue. Operative biopsy revealed plexiform neurofibroma. Because of the patient's operative risk and the potential morbidity of surgical resection, he was treated with three-dimensional conformal radiotherapy (3DCRT). His treatment was accomplished using a five-field arrangement treating exclusively the mass lesion to a total tumor dose of 60 Gy. After treatment, the patient's tongue pain resolved, and he noted minimal transient xerostomia. Serial follow-up radiographic examinations showed the base of tongue mass to be slightly smaller 4 months after treatment. The most recent follow-up magnetic resonance image reveals a further decrease in size of the mass. The patient is now over 3 years out from treatment. CONCLUSIONS: Solitary plexiform neurofibroma of the tongue base is a rare tumor. These benign neoplasms are usually treated with either observation or surgical excision. This case demonstrates that, when significant symptoms necessitate active management, these lesions may be successfully treated with minimal morbidity using 3DCRT. The ability of this technique to deliver a conformal radiation dose to the tumor volume while sparing the surrounding normal tissues may expand the application of radiotherapy in the treatment of these benign lesions of the head and neck.

Drug- and radiation-induced resistance in a human neurogenic sarcoma xenografted in nude mice.

The in vivo development of radiation- and doxorubicin-induced resistance was studied in a chemosensitive and radiosensitive human neurogenic sarcoma (Essen neuroectodermal tumor line 2) xenografted in nude mice. Dose-response curves were generated for the parent tumor line, and growth delay (GD) and specific growth delay (SGD) were the study end points. An intravenous injection of doxorubicin at 10 mg/kg, the lethal dose for 10% of the study population (LD10) in nude mice, and a single dose of 12 Gy radiation were determined to be isoeffective and were thus maintained for all subsequent treatments. For the induction of resistance to both treatment modalities, regrowing tumors were transplanted into successive generations of nude mice and retreated. This procedure was repeated 13 and 9 times, respectively, for the doxorubicin and radiation treatments. The response was monitored in all passages. As compared with the parent tumor line, a 50% decrease in SGD was observed following 3.9 and 8.5 treatments with doxorubicin and radiation, respectively. Following four treatments with doxorubicin, SGD in tumors crossed over to radiation therapy declined by 50%. Radiation therapy, on the other hand, caused significant reductions in GD and SGD in tumors that were subsequently exposed to doxorubicin, but it did not induce a 50% decline in response. Overexpression of P-170-glycoprotein was not observed for either treatment modality. The data suggest that treatment with doxorubicin or radiation can potentially induce resistance to subsequent continued or crossover treatment and that this resistance develops gradually. The lack of P-170-glycoprotein over-expression in the resistant cell lines indicates the existence of alternative pathways that may lead to resistance.

The TCD50 and regrowth delay assay in human tumor xenografts: differences and implications.

The response to irradiation of five human xenograft cell lines--a malignant paraganglioma, a neurogenic sarcoma, a malignant histiocytoma, a primary lymphoma of the brain, and a squamous cell carcinoma--were tested in nude mice. All mice underwent 5 Gy whole body irradiation prior to xenotransplantation to minimize the residual immune response. The subcutaneous tumors were irradiated at a tumor volume of 120mm3 under acutely hypoxic conditions with single doses between 8 Gy and 80 Gy depending on the expected radiation sensitivity of the tumor line. Endpoints of the study were the tumor control dose 50% (TCD50) and the regrowth delay endpoints growth delay, specific growth delay, and the tumor bed effect corrected specific growth delay. Specific growth delay and corrected specific growth delay at 76% of the TCD50 was used in order to compare the data to previously published data from spheroids. The lowest TCD50 was found in the lymphoma with 24.9 Gy, whereas the TCD50 of the soft tissue sarcomas and the squamous cell carcinoma ranged from 57.8 Gy to 65.6 Gy. The isoeffective dose levels for the induction of 30 days growth delay, a specific growth delay of 3, and a corrected specific growth delay of 3 ranged from 15.5 Gy (ECL1) to 37.1 Gy (FADU), from 7.2 Gy (ENE2) to 45.6 Gy (EPG1) and from 9.2 Gy (ENE2) to 37.6 Gy (EPG1), respectively. The corrected specific growth delay at 76% of the TCD50 was correlated with the number of tumor rescue units per 100 cells in spheroids, which was available for three tumor lines, and with the tumor doubling time in xenografts (n = 5). The TCD50 values corresponded better to the clinical experience than the regrowth delay data. There was no correlation between TCD50 and any of the regrowth delay endpoints. This missing correlation was most likely a result of large differences in the number of tumor rescue units in human xenografts of the same size.

Radiation response in 10 high-grade human soft tissue sarcoma xenografts to photons and fast neutrons.

From a panel of 48 human soft tissue sarcomas growing as permanent xenografts, 10 tumor lines (five leiomyosarcomas, three malignant fibrous histiocytomas, two neurofibrosarcomas) have been selected to determine the radiation response to photons and fast neutrons. Using the specific growth delay (SGD) as an end-point, considerable variability of inherent radiosensitivity was observed. Isoeffective radiation doses varied by a factor of 27 for photons and of 9.4 for neutrons at a specific growth delay level of 0.5. The heterogeneity of the relative biological effectiveness (RBE) at this specific growth delay-level differed by a factor of 8. Relative biological effectiveness values for clamped tumors exceeded those of the normal tissues (RBE approximately 3) in 6 out of 10 tumor lines. Assuming a ratio of 0.5 for oxygen enhancement ratio-values of neutrons and photons, a therapeutic gain for neutrons existed in 4 out of 10 tumor lines under oxic conditions. No correlation between volume doubling times and relative biological effectiveness was seen.

[Extra-abdominal spread of pelvic neoplasms. CT evaluation and radiotherapeutic implications]. / Diffusione extra-addominale delle neoplasie pelviche. Valutazione TC ed implicazioni radioterapiche.

Meyers and other authors have described the extra-abdominal spread of inflammatory abdominal diseases. Conversely, little attention has been paid to the extra-abdominal spread of pelvic neoplasms. The authors have detected, by means of CT, 17 cases of extra-abdominal neoplastic spread in a series of 203 patients with pelvic neoplasms. Neoplastic spread involved the inguinal region in 1 case, the buttock in 6 cases, and the ischiorectal fossa and/or perineum in 12 cases, with more than one region involved in some patients. In such cases CT showed the extension of tumoral tissue beyond the muscular walls of the pelvis. Recurrent pelvic carcinomas are the most common neoplasms spreading outside the pelvis. Surgical obliteration of the pelvic fasciae can explain such a behavior. Differential diagnosis is to be made with inflammatory pelvic diseases with extrapelvic spread. When a pelvic tumor spreads outside the pelvis it can be seen as a primitive gluteal or inguinal or perineal mass. CT demonstration of such an insidious event is mandatory for both a correct diagnosis and radiation treatment planning.

[Pathologic dens fracture in irradiated malignant neurofibroma]. / Pathologische Densfraktur beim bestrahlten malignen Neurofibrom.

A pathological dens fracture in a 47 year old patient with malignant neurofibroma is described. These tumours are very rare but the prognosis is very poor because of rapid proliferation and early metastatic progression. In the described case, bone osteolysis remained unnoticed until manifestation of clinical symptoms. The pathological fracture occurred despite irradiation of the dens.

Resection of a tumor of the psoas muscle.

A 16-year-old boy presented with paresthesias and weakness of the right thigh. A computerized axial tomography scan identified a mass within the right psoas muscle, and a needle biopsy showed a primitive neuroectodermal tumor, which did not respond to two courses of chemotherapy (Adriamycin, vincristine, and cytoxan). An anatomic resection of the psoas muscle and femoral nerve was performed and radiotherapy administered. The boy remains ambulatory and free of disease 2.5 years after resection.

Orbital malignant peripheral nerve sheath tumours.

We describe three patients with malignant peripheral nerve tumours in the orbit and review the existing literature on these rare lesions.

Radiotherapy of soft tissue sarcomas in dogs.

Megavoltage radiotherapy was administered to 42 dogs with soft tissue sarcoma. Acceptable local control of these aggressive tumors was achieved after one year of treatment. Control rates of 48 and 67% were obtained at doses of 45 and 50 gray (Gy), respectively. At 2 years, control rates decreased to 33% at the dose of 50 Gy. Serious complications developed in 4 of 42 dogs at doses of 40 to 50 Gy. The estimated dose with a 50% probability for causing serious complications was 54 Gy, given in 10 fractions. We believe that the large doses per fraction used in this study probably led to an increased probability for necrosis. Hemangiopericytomas seemed to be more responsive than fibrosarcomas. Only 2 of 11 recurrent tumors were controlled with surgery. Good local control was achieved with radiation alone for one year at doses with a low probability for serious complications; however, higher total radiation doses or combined modalities, such as surgery and radiation or radiation and hyperthermia, may be needed for longer-term control.

Radiation port dermatophytosis.

We report two cases in which dermatophytic infection developed almost entirely within a radiation field mimicking an acute radiation effect. Radiotherapists and dermatologists should be aware of this possibility and be able to differentiate it from radiation dermatitis. Topical antifungal agents are the recommended treatment after diagnosis is established.

Tumors of the peripheral nervous system.

Most nerve tumors (benign and malignant) do not arise from the nerves per se, but from the supporting cells; tumors arising from the cells of Schwann are termed schwannoma or neurilemmoma-benign or malignant. Surgical extirpation is the most effective treatment for these tumors. Radiation therapy can offer significant palliation and prolongation of life, but no cures have been observed. Benign tumors can be treated by local surgical extirpation; malignant tumors must be radically resected, including major amputation where indicated. Neurofibromatosis (von Recklinghausen's disease) is a genetic error of metabolism with a proclivity to produce multiple neurofibromas and, in about 10% of the patients, malignant neurilemmomas. Of 100 patients with malignant neurilemmomas treated by the author, 74 were considered determinate; among them, the 10-year "cure" rate was 32%. Patients with von Recklinghausen's disease had almost as good a 10-year survival rate as those with solitary malignant schwannoma (30% vs. 39%).

The role of radiation therapy in the treatment of sarcoma of soft tissue.

The data presented indicate that the combination of function-preserving surgery and radiation therapy is of value in the treatment of soft tissue sarcomas of the extremity. Local control is obtained in approximately 85% of patients and with survival results comparable to those obtained in patients treated with radical surgery. The one randomized series of patients treated with conservative resection and radiation compared to amputation has shown no difference in overall survival. These local control results have been obtained while maintaining good functional results. Combined local resection and radiation is an appropriate treatment option in a large proportion of patients with soft tissue sarcomas.

Response of sarcomas of bone and of soft tissue to neutron beam therapy.

A total of 51 patients were treated at Fermilab for sarcoma of bone (25 patients) and soft tissue (26 patients). Neutrons were delivered in twice weekly fractions over 6-7 weeks to total doses between 18 and 26 Gy. Long-term local control (greater than 2 years) was achieved in 24 patients (47%). Overall local control rates were 44% in the bone sarcomas and 50% in the soft tissue tumors. Chondrosarcoma appeared relatively more responsive with 9 out of 16 (56%) controlled, compared to osteogenic sarcoma with 2 out of 9 (22%) controlled. Among the soft tissue tumors, liposarcoma (5/7 controlled) and neurogenic sarcoma (3/3 controlled) appear to be more responsive than other tumors. The overall survival rate was 40% in the entire series. These results are comparable with international experience in neutron therapy of sarcomas of bone and soft tissues. Out of 263 soft tissue sarcomas treated with neutrons only to full dosage throughout the world, 152 (58%) were locally controlled. Similarly out of 74 sarcomas of bone so treated, 44 (60%) were controlled.