Sarcomas subsequent to cranial irradiation

Sarcomas of the sellar region: a systematic review

PURPOSE AND METHODS

Sarcomas of the sellar region are uncommon and unexpected tumors. Here, we review the cases reported in literature via a systematic search.

RESULTS

Ninety-four patients, 58.5% male with mean age of 39.2 ± 17.2 years were included. Fifty-seven (62%) had soft tissue sarcomas (STS) and 35 (38%) bone sarcomas (BS). Sarcoma was a primary tumor in 66%, developed after radiotherapy in 31.9% and 7.4% were metastatic. Median time between radiotherapy and sarcoma development was 10.5 (11) years. Main presentation symptoms were visual disorders (87.9%), headache (61.5%) and III cranial nerve palsy (24.1%). After surgery, sarcoma persisted or recurred in 82.3% and overall mortality reported was 44.6% with 6.5 (14) months of median survival. Tumor appeared earlier in BS compared to STS (34.4 ± 15.1 vs. 42.6 ± 17.6 years), p = 0.034 and complete tumor resection was achieved more often (41.3% vs. 4.4%), p =  < 0.001. Condrosarcoma and rhabdomyosarcoma were more frequent subtypes among primary tumors while fibrosarcoma was among post-radiation sarcomas. Tumor size was larger in radiation associated sarcomas (mean maximum diameter 46.3 ± 9.3 vs. 29.1 ± 8.0 mm, p = 0.004) and persistency/recurrence was similar in both groups (70.1 vs. 73.3%, p = 0.259).

CONCLUSION

Sarcomas appear as mass effect symptoms in the middle aged population, mainly as primary tumors, but one third is associated with radiotherapy. Surgery is commonly not curative, mortality rate is high and death ensues shortly after diagnosis.

Primary intracranial fibrosarcoma in a southern sea otter Enhydra lutris nereis

Southern sea otters Enhydra lutris nereis, a threatened marine mammal species, face numerous environmental and infectious disease challenges in their native habitat of coastal California, USA. However, there are few published cases describing neoplasia in sea otters despite their relatively long life span when cared for in aquarium settings. An 18 yr old neutered male southern sea otter, born and raised in human care, presented with an acute onset of seizures and dull mentation. Magnetic resonance imaging of the head revealed a large, central brain lesion. After no improvement with treatment, euthanasia was elected due to a poor prognosis. Grossly, a poorly demarcated, granular, tan mass expanded the cranial meninges in the longitudinal fissure at the level of the cruciate sulcus and extended into the underlying gray matter and superficial white matter. Histologically, the mass was composed of spindle cells, forming haphazardly arranged interlacing bundles and herringbone patterns, with a high mitotic count, moderate cellular pleomorphism, and prominent vascularization. Neoplastic cells demonstrated positive immunoreactivity for vimentin and negative immunoreactivity for smooth muscle actin, factor VIII-related antigen, S100, melan-A, E-cadherin, desmin, glial fibrillary acidic protein, and cytokeratin AE1/AE3. Based on gross, histologic, and immunohistochemical findings, the mass was most consistent with a primary intracranial fibrosarcoma (PIF). PIFs are a rare neoplasm in both humans and other animals with few reports in the veterinary literature. This is the first recorded case of a PIF in a sea otter.

Secondary Intracranial Tumors Following Radiotherapy for Pituitary Adenomas: A Systematic Review

Pituitary adenomas are often treated with radiotherapy for the management of tumor progression or recurrence. Despite the improvement in cure rates, patients treated by radiotherapy are at risk of development of secondary malignancies. We conducted a comprehensive literature review of the secondary intracranial tumors that occurred following radiotherapy to pituitary adenomas to obtain clinicopathological characteristics. The analysis included 48 neuroepithelial tumors, 37 meningiomas, and 52 sarcomas which were published between 1959–2017, although data is missing regarding overall survival and type of irradiation in a significant proportion of the reports. The average onset age for the pituitary adenoma was 37.2 ± 14.4 years and the average latency period before the diagnosis of the secondary tumor was 15.2 ± 8.7 years. Radiotherapy was administered in pituitary adenomas at an average dose of 52.0 ± 19.5 Gy. The distribution of pituitary adenomas according to their function was prolactinoma in 10 (7.2%) cases, acromegaly in 37 (27.0%) cases, Cushing disease in 4 (2.9%) cases, PRL+GH in 1 (0.7%) case, non-functioning adenoma in 57 (41.6%) cases. Irradiation technique delivered was lateral opposing field in 23 (16.7%) cases, 3 or 4 field technique in 27 (19.6%) cases, rotation technique in 10 (7.2%) cases, radio surgery in 6 (4.3%) cases. Most of the glioma or sarcoma had been generated after lateral opposing field or 3/4 field technique. Fibrosarcomas were predominant before 1979 (p < 0.0001). The median overall survival time for all neuroepithelial tumors was 11 months (95% confidence intervals (CI), 3–14). Patients with gliomas treated with radiotherapy exhibited a non-significant positive trend with longer overall survival. The median overall survival time for sarcoma cases was 6 months (95% CI, 1.5–9). The median survival time in patients with radiation and/or chemotherapy for sarcomas exhibited a non-significant positive trend with longer overall survival. In patients treated with radiotherapy for pituitary adenomas, the risk of secondary tumor incidence warrants a longer follow up period. Moreover, radiation and/or chemotherapy should be considered in cases of secondary glioma or sarcoma following radiotherapy to the pituitary adenomas.

Radiation-induced osteosarcoma of the skull base after radiation therapy in a patient with nasopharyngeal carcinoma: a case report and review of the literature

Background

Radiation-induced osteosarcomas are a recognized complication of radiation therapy. Owing to the fact that it is rare, publications on radiation-induced osteosarcoma of the skull base are limited to a small series and some case reports.

Case presentation

We describe a rare case of a patient with a skull base radiation-induced osteosarcoma treated 11 years before with ionizing radiation for an undifferentiated carcinoma of the nasopharynx. The patient was treated with chemotherapy alone, but he died after the third cycle.

Conclusions

Radiation-induced osteosarcoma of the skull base after treatment of nasopharyngeal carcinoma is a very rare but very aggressive complication with a poor prognosis. Chemotherapy gives bad results, and regular follow-up of treated patients should be considered.

Glioblastoma following radiosurgery for meningioma

We report a patient who underwent gamma knife radiosurgery to treat recurrent meningioma after microsurgery and thereafter developed secondary malignancy adjacent to the original tumor. A 47-year-old woman had underwent resection of the olfactory groove meningioma. Then radiosurgery was done three times over 4 year period for the recurrent tumor. After 58 months from the initial radiosurgery, she presented with headache and progressive mental dullness. Huge tumor in bifrontal location was revealed in MRI. Subsequent operation and pathological examination confirmed diagnosis of glioblastoma. This case fits the criteria of radiation-induced tumor and the clinical implication of the issue is discussed.

A case of high-grade undifferentiated sarcoma after surgical resection and stereotactic radiosurgery of a vestibular schwannoma

Stereotactic radiosurgery has become a more frequently used treatment modality for vestibular schwannomas; a few reports of malignant transformation and/or radiation-associated tumors have surfaced. The majority of these reported cases were in patients with underlying neurofibromatosis. The authors report a case of a 74-year-old man with rapid progression of a cerebellar-pontine angle tumor 14 years after surgical resection of a vestibular schwannoma (VS) from the same site, and 6 years after stereotactic radiosurgery. A pathological study of the recent tumor showed a high-grade spindle cell neoplasm that bore no resemblance to the initial schwannoma. The patient had no diagnosis of neurofibromatosis. Secondary malignancy occurred in a non-neurofibromatosis patient 6 years after stereotactic radiosurgery. It is our belief that documentation of such cases will provide important evidence that helps evaluate the long-term effect of radiosurgery for VS. Such observations can influence clinical decisions regarding the choice of treatment modalities.

Malignant transformation of acoustic neuroma/vestibular schwannoma 10 years after gamma knife stereotactic radiosurgery

Only a handful of cases of de-novo malignancies of the vestibulocochlear nerve have been reported. Even rarer is the malignant transformation of a previously histologically diagnosed benign vestibular schwannoma. We present the case of a young adult who had combined operative/Gamma knife treatment for a benign vestibular schwannoma, followed by further surgery 2 years later. He represented 10 years after original diagnosis with facial numbness and ataxia, MRI showing gross tumor recurrence. After radical resection, histology showed malignant transformation to a malignant peripheral nerve sheath tumor. Within 3 months there was rapid, aggressive recurrence with brainstem compression, requiring further surgery for brainstem decompression. Histology confirmed further de-differentiation to an anaplastic sarcoma. While awaiting radiotherapy the tumor recurred again, the patient succumbing. The patient had no features of neurofibromatosis type 2. In the literature there are 13 other cases of malignant vestibular schwannomata. Only six had radiotherapy and of these only two had histological confirmation of a benign lesion preradiotherapy. Neither of these had neurofibromatosis. Three other cases had histological proof of malignancy postradiosurgery, but with no preradiotherapy histology; of these, two were positive for neurofibromatosis. The tumor biology of vestibular schwannomata as well as the radiobiology in the context of malignant transformation is discussed.

Sarcoma of the sella after radiotherapy for pituitary adenoma

Secondary malignancies are infrequent sequelae of pituitary radiotherapy. The goal of the present case study is to analyze clinical features of a selected group of cases to define the special characteristics of these tumors. We report the illustrative case of a 38-year-old man with acromegaly who had transsphenoidal surgery and radiotherapy 7 years before presenting with a sellar high-grade sarcoma. Transsphenoidal and transcranial resection, as well as repeated gamma knife radiosurgery, could not prevent tumor progression and development of meningiosis sarcomatosa. We performed a thorough search of the literature and reviewed numerous publications and reports on primary and secondary sarcomas of the sella. Our search revealed 51 cases of mesenchymal malignancies after sellar radiotherapy. For further analysis, we identified and selected a group of patients based on the criteria for studying radiation-induced tumors as described by Cahan.Compared to the surgically treated group, secondary sarcomas of the sella are more frequent in patients who have had radiotherapy. These tumors occur at normal dose schedules with long latencies. Their growth is very aggressive and they may develop meningiosis sarcomatosa. Until now, no treatment modalities have been able to stop the progression of these neoplasms. Radiation-induced sarcoma is a rare sequela of pituitary radiotherapy. It is important for the treating physician to keep in mind the possibility of post-radiation sarcoma development. Additionally, one must include these tumors into the differential diagnosis in pituitary patients presenting with tumor recurrence more than 5 years after radiotherapy in combination with a secondary lack of hormonal activity.

Malignant fibrous histiocytoma of the head and neck region

BACKGROUND

Malignant fibrous histiocytoma (MFH) is 1 of the most common soft tissue sarcomas in the head and neck.

METHODS

We conducted a retrospective review of patients with MFH of the head and neck region at a large multidisciplinary cancer center between 1973 and 2005.

RESULTS

Ninety-five patients were included in the study. The median age at diagnosis was 53 years (range, 3-90 years); 69% of the patients were men. The parotid or neck was the most common subsite (35%), and 23% of the cases were associated with prior radiation exposure. Although there were no significant differences in the distribution of age, sex, year of presentation, tumor location, size, local extension, or treatment between patients with and without prior radiation exposure, those with radiation-associated tumors were more likely to have positive or unclear surgical margins (p = .037). With a median follow-up of 34 months, 32 (39%) of the 83 patients treated at M. D. Anderson Cancer Center with curative intent had a recurrence (isolated local recurrence in 18, isolated distant recurrence in 8, both local and distant recurrence in 5, and regional recurrence in 1). For patients treated at our institution with curative intent, 5-year overall, disease-free, and disease-specific survival rates were 55%, 44%, and 69%, respectively. Prior radiation exposure and positive margins were associated with worse survival.

CONCLUSION

MFH of the head and neck region is often aggressive and characterized by local and/or distant recurrence and poor survival. Radiation-associated tumors seem to have an especially poor prognosis. Based on a significant body of literature, multidisciplinary evaluation and treatment of such high-grade sarcomas is encouraged.

Neurotoxicity of radiation therapy

Direct or incidental exposure of the nervous system to therapeutic irradiation carries the risk of symptomatic neurologic injury. Central nervous system toxicity from radiation includes focal cerebral necrosis, neurocognitive deficits, and less commonly cerebrovascular disease, myelopathy, or the occurrence of a radiation-induced neoplasm. Brachial or lumbosacral plexopathy are the most common syndromes of radiation toxicity affecting the peripheral nervous system. This article focuses on the clinical features, diagnosis, and management options for patients with radiation neurotoxicity.

Metachronous gliomas following cranial irradiation for mixed germ cell tumors

INTRODUCTION

Cranial irradiation has been widely used as a therapeutic tool for treating various lesions, particularly neoplastic diseases. Even though radiation therapy is usually well-tolerated, it occasionally causes clinically significant long-term toxicity such as radiation necrosis and irradiation-related arteriopathy with stroke.

DISCUSSION AND CASE REPORT

The development of neoplasms following therapeutic cranial irradiation is also rare, but may cause serious and potentially fatal complications. Various radiation-induced tumors, including meningioma, glioma, and sarcoma have been reported (Child Nerv Syst 24:793-805, 12). However, metachronous intracranial double tumors induced by radiation therapy are extremely rare. In here, we report a case of metachronous different gliomas including astrocytoma and glioblastoma following irradiation therapy after 41 and 46 months, respectively.

Rapid growth of primary cerebral fibrosarcoma with conversion to glioblastoma at second recurrence

We present a case of de novo fibrosarcoma in a 43-year-old male, with MRI documented evolution from a 5 mm hyperintense area to 5 cm tumor mass in a 12-month period. The diagnosis of low-grade fibrosarcoma was established by three experienced neuropathologists. The patient underwent gross total resection with adjuvant fractionated conformal radiotherapy. Following first recurrence 3 months later, the patient was reoperated and stereotactic radiosurgery of a residual tumor was performed thereafter. The pathological diagnosis was similar, but with additional extensive radiation effects. Six months later the patient underwent aggressive surgical resection for second recurrence. The pathological diagnosis was WHO grade IV glioblastoma. The etiology of this highly unusual progression from primary mesenchymal neoplasm to high-grade glioma is discussed.

Two metachronous tumors induced by radiation therapy: case report and review of the literature

Various radiation-induced tumors, including meningioma, glioma, and sarcoma, have been reported; however, metachronous intracranial double tumors induced by radiation therapy are extremely rare. A 1-year-old boy had undergone tumor removal and craniospinal radiation therapy (30 Gy) for cerebellar medulloblastoma. At 24 years old, parasagittal meningioma developed in the left parietal region and was totally removed. Six years later, an infiltrative tumor was newly found in the right fronto-temporal white matter. The patient underwent stereotactic biopsy, and the tumor was found to be an anaplastic astrocytoma. Chromosomal analysis by fluorescence in situ hybridization (FISH) revealed loss of heterozygosity (LOH) of 1p. As the patient had previously had craniospinal irradiation, no additional radiation therapy was delivered. He underwent chemotherapy with temozolomide and the disease is now stable. Since both secondary tumors were located within the area of previous radiation and the patient did not have any genetic disease predisposing him to tumors, radiation therapy was considered to be responsible for their tumorigenesis. To our knowledge, this case is the fourth case of radiation-induced double CNS tumors arising after radiotherapy to be described in the literature. Whenever radiation is administered to children or young adults, careful serial screening studies are needed.

Masson's tumour in the right parietal lobe after stereotactic radiosurgery for cerebellar AVM: case report and review

We present a 50-year-old patient who had undergone stereotactic radiosurgery for a cerebellar vermian arteriovenous malformation. On routine surveillance MR imaging a lesion suggestive of a meningioma was demonstrated and removed. Histologically it was found to be intravascular papillary endothelial hyperplasia (Masson's tumour). The characteristic radiological and histological findings are presented. Aspects of management of this rare tumour are discussed. Given that cases are often found in combination with a vascular abnormality, we discuss the possibility of a change in local haemodynamics after radiosurgery promoting development of this tumour.

Metachronous secondary atypical meningioma and anaplastic astrocytoma after postoperative craniospinal irradiation for medulloblastoma

INTRODUCTION

Malignant brain tumors have been reported to occur after childhood irradiation more frequently than in the nonirradiated population.

DISCUSSION

In this study, we report the case of a 15-year-old boy treated for medulloblastoma with surgery and craniospinal radiotherapy, who developed a meningioma 18 years after initial treatment and subsequently an anaplastic astrocytoma 23 years after primary treatment. The meningioma was resected without complications. The patient is currently alive but with recurrent astrocytoma after a complete remission on temozolomide monotherapy. Second malignancies are a rare, potentially devastating risk in cancer survivors, with risk continuing lifelong.

Radiotherapy and wound healing

Radiotherapy is an invaluable weapon when treating cancer. However, the deleterious effects of radiation, both immediate and long-term, may have a significant effect on local tissues. Problematic wound healing in radiation-damaged tissue constitutes a major problem that is frequently overlooked during the management of patients who require radiotherapy, or have had radiotherapy in the past. Poor wound healing may lead to chronic ulceration, pain, secondary infection and psychological distress and compromise the outcome of general or reconstructive surgery. We discuss the pathophysiology of poor wound healing following radiotherapy, specific problems for radiation-damaged tissue and potential treatments to improve wound healing of irradiated tissues.

Evaluation of fractionated radiotherapy and gamma knife radiosurgery in cavernous sinus meningiomas: treatment strategy

OBJECTIVE

To investigate the respective role of fractionated radiotherapy (FR) and gamma knife stereotactic (GKS) radiosurgery in cavernous sinus meningioma (CSM) treatment.

METHODS

The authors report the long-term follow-up of two populations of patients harboring CSMs treated either by FR (Group I, 38 patients) or GKS radiosurgery (Group II, 36 patients). There were 31 females with a mean age of 53 years in Group I and 29 females with a mean age of 51.2 years in Group II. In 20 patients (Group I) and 13 patients (Group II), FR and GKS radiosurgery were performed as an adjuvant treatment. In 18 patients (Group I) and in 23 patients (Group II), FR and GKS radiosurgery were performed as first line treatment. In our early experience with GKS radiosurgery (1992, date of gamma knife availability in the department), patients with tumors greater than 3 cm, showing close relationship with the optic apparatus (<3 mm) or skull base dural spreading, were treated by FR. Secondarily, with the advent of new devices and our growing experience, these criteria have evolved.

RESULTS

The median follow-up period was 88.6 months (range, 42-168 mo) for Group I and 63.6 months (range, 48-92 mo) for Group II. According to Sekhar's classification, 26 (68.4%) patients were Grade III to IV in Group I and 10 (27.8%) patients in Group II (P < 0.05); 23 (60.5%) patients had extensive lesions in Group I and 7 (19.4%) patients in Group II (P < 0.05). Mean tumor volume was 13.5 cm in Group I and 5.2 cm in Group II (P < 0.05). Actuarial progression-free survival was 94.7% and 94.4% in Group I and II, respectively. Clinically, improvement was seen for 24 (63.2%) patients in Group I and for 21 (53.8%) patients in Group II (P > 0.05). Radiologically, 11 (29%, Group I) patients and 19 (Group II, 52.7%) patients showed tumor shrinkage (P = 0.04). Transient morbidity was 10.5% in Group I and 2.8% in Group II. Permanent morbidity was 2.6% in Group I and 0% in Group II.

CONCLUSION

FR and GKS radiosurgery are safe and efficient techniques in treatment of CSMs, affording comparable satisfactory long-term tumor control. However, GKS radiosurgery provides better radiological response, is far more convenient, and fits into most patients lives much better than FR. Therefore, in the authors' opinion, GKS radiosurgery should be advocated in first intention for patients with CSMs, whereas conventional radiotherapy should be reserved for cases that are not amenable to this technique, thus making these two therapeutic modalities not alternative but complementary tools in CS meningioma treatment strategy.

Primary giant congential infantile fibrosarcoma of the scalp: case report and review of literature

CASE REPORT

A primary giant infantile fibrosarcoma of the scalp in a 6-month-old boy is reported. He presented with a rapidly enlarging right paramedian parietal scalp swelling since birth. There were no signs of raised intracranial tension. Magnetic resonance (MR) imaging of the brain revealed a large vascular scalp tumor extending over the posterior frontal and parietal region bilaterally crossing the midline. There was no intracranial extension. Carotid angiography revealed an extremely vascular tumor supplied by the external carotid artery branches. The tumor was completely resected through a curvilinear scalp incision. Histology was consistent with diagnosis of an infantile fibrosarcoma. The patient had an uneventful course and received no postoperative adjuvant therapy. MR imaging of the brain at follow-up after 5 years showed no evidence of recurrence of tumor. At follow-up after 10 years, he is asymptomatic and leading an active life.

DISCUSSION

The pathology and management of primary scalp fibrosarcoma is discussed, and the relevant literature is briefly reviewed.

Second malignancies in pediatric patients: imaging findings and differential diagnosis

Therapeutic advances in the treatment of pediatric neoplasms have improved the prognosis but have also increased the risk of developing rare second malignant neoplasms (SMNs). Primary neoplasms that are often associated with SMNs include lymphoma, retinoblastoma, medulloblastoma, neuroblastoma, and leukemia. The most common SMNs are central nervous system (CNS) tumors, sarcomas, thyroid and parotid gland carcinomas, and leukemia, particularly acute myeloblastic leukemia. Genetic predisposition, chemotherapy, and especially radiation therapy are implicated as pathogenic factors in SMN. All survivors of childhood cancer should have lifelong follow-up, preferably with magnetic resonance imaging, which does not require ionizing radiation and provides greater anatomic detail and resolution in the head and neck region and the CNS. A new or progressive lesion may represent recurrence of the primitive neoplastic process, late radiation injury, or, more infrequently, an SMN. Differential diagnosis can be very difficult, and outcome is often fatal. Treatment protocols should be modified to reduce the risk for SMN without compromising the effectiveness of initial therapy. Clinicians should individualize treatment for patients who are genetically predisposed to SMN. In addition, radiologists should be familiar with the long-term consequences of antineoplastic therapy to facilitate diagnosis and anticipate adverse outcomes.

Neurologic complications of radiation therapy

Injury to the central and peripheral nervous systems is an increasingly frequent consequence of standard radiation treatment protocols for tumors involving or adjacent to nervous system structures. Characteristic temporal, clinical, radiographic, and laboratory features distinguish a number of specific radiation injury syndromes, but meticulous and repeated evaluations over time are often required to establish a diagnosis. These syndromes vary with regard to prognosis and therapeutic options, and competing diagnoses with very different natural histories and therapies often mask or mimic the signs and symptoms of radiation-related nervous system injury. The ability to efficiently negotiate this complicated differential diagnostic landscape allows for early diagnosis of tumor recurrence or an alternative etiology, prompt institution of appropriate therapy, avoidance of unnecessary diagnostic studies, and confident prognostication for patients and families. Even after the diagnosis of a radiation-related complication is made, continued vigilance for additional sites or manifestations of radiation injury is mandatory. Meanwhile, further research into treatment, prevention, and the causes of individual susceptibility to radiation injury are essential.

Post-radiation dedifferentiation of meningioma into osteosarcoma

BACKGROUND

A number of osteoblastic meningiomas, primary osteosarcomas of the meninges, and post-radiation osteosarcomas of the head have been reported. However, postradiation dedifferentiation of meningioma into osteosarcoma has not been reported previously.

CASE PRESENTATION

In 1987 a caucasian man, then 38 years old, presented with a pituitary macroadenoma. He underwent a subtotal resection of the tumor and did well until 1990 when a recurrent tumor was diagnosed. This was treated with subtotal resection of the tumor, followed by radiation therapy for six weeks to a total of 54 Gy. He was considered "disease-free" for nearly ten years. However, most recently in July 2000, he presented with a visual field deficit due to a second recurrence of his pituitary macroadenoma, now with suprasellar extension. At this time, as an incidental finding, a mass attached to the dura was noted in the left parietal hemisphere. This dura-based mass had grown rapidly by January 2001 and was excised. It showed histological, immunohistochemical, and electron microscopic features of malignant meningioma and osteosarcoma with a sharp demarcation between the two components.

CONCLUSIONS

We report a rare case of a radiation induced dedifferentiation of meningioma into osteosarcoma, which has not been reported previously.

Gamma knife radiosurgery and its possible relationship to malignancy: a review

✓ The question has been raised recently whether gamma knife radiosurgery (GKS) can induce secondary neoplasia. Because there is little or no detailed knowledge about this potential complication, background information culled from the radiotherapy literature is reviewed as a guide to the clinical situations in which radiotherapy may induce secondary neoplastic change. Available case reports are then reviewed and discussed against the background of the current knowledge. On the basis of the review, the following suggestions are proposed on how to limiting the extent of this complication, document its frequency, and inform patients. It should be remembered that: the benefits of GKS are great; its alternatives also have risks; there often are no alternatives to GKS; follow-up documentation should be pursued more actively so that, if possible, no patient falls through the net; practitioners should be proactive in defining the problem, and genetic analysis of tumor biopsy specimens obtained in patients who will undergo or have undergone GKS should become routine; the extent of secondary neoplasia is not known; and patient information should be guided by what is known rather than by what is feared.

Acoustic neuroma with malignant transformation. Case report

The authors describe the case of a 57-year-old woman who had a right-sided hearing disturbance that had remained untreated for 1 year. The diagnosis was of a right cerebellopontine angle tumor, and the patient underwent its removal via retrosigmoid approach. Pathologically, the tumor was a typical benign neuroma. Growth of residual tumor was detected 4 years after the initial operation, and it was treated with gamma knife surgery (GKS). Six months later, the tumor had grown, and the patient underwent surgery via a combined retrosigmoid-translabyrinthine approach. Abnormal mitotic figures were observed on histological studies, indicating that the tumor had become malignant. Thereafter, the tumor grew rapidly, and the patient died 6.5 years after the initial treatment. It cannot be ruled out that GKS affected the outcome, but the causal sequence was unclear. Because such a patient is rare, documentation of the case was considered clinically important.

[Radiation-induced intracerebral sarcoma]

We report a case of radiation-induced sarcoma in a 50 year-old male patient who was treated with total resection and radiation for right temporal lobe PNET. He received a dose of 60-Gy. A sequential magnetic resonance image 32 months after the completion of radiation therapy and 34 months after surgery showed a mass in the right temporal cerebral convexity. The postoperative diagnosis was sarcoma. Two years later the patient was operated because of a new lesion with similar characteristics. The follow up from the PNET diagnosis is 5 years and 10 months and the survival from sarcoma diagnosis is now 3 years and there is no evidence of recurrence. The development of sarcoma subsequent to cranial irradiation is an infrequent event but it should be considered in the differential diagnosis of a lesion that progresses several years after radiation therapy or when a new lesion appear.

Postradiation sarcomas: 20 cases and a literature review

PURPOSE

To analyze 20 cases of postradiation sarcoma (PRS) to determine dose levels at which this condition developed, the pathology of the initial and postradiation tumors, latency period, and outcome; and to review the literature and propose modified criteria for diagnosis.

METHODS AND MATERIALS

Patient records were reviewed. Previous radiation fields and isodose charts were reconstructed to determine the dose received in the tissue in which the PRS subsequently developed.

RESULTS

There were 16 female patients and 4 male patients. Mean age at the time of initial radiotherapy was 28 years. Mean latency was 14 years, with no difference in latency between the adult and pediatric group (t = 0.45, p = 0.37), but shorter latency in the retinoblastoma than in the nonretinoblastoma patients (t = 3.18, p = 0.003). The outcome was poor; 2 patients were alive and disease-free at 2 and 5 years. The 18 patients who died as a result of PRS had a median survival of 1 year.

CONCLUSION

PRSs are rare. Unnecessary radiation must be avoided. Cases should be reported with full details so that risk factors can be ascertained. PRSs usually arise in moderate to higher dose areas. Diagnostic criteria should allow soft tissue tumors and short latency.

Death from a malignant cerebellopontine angle triton tumor despite stereotactic radiosurgery. Case report

Malignant vestibular nerve tumors are rare: to date, only three cases have been reported in the literature. The authors report a case of an eighth cranial nerve tumor that progressed 5 years after stereotactic radiosurgery. The patient was a 44-year-old man who underwent stereotactic radiosurgery for a 27-mm cerebellopontine angle tumor that was discovered on investigation of tinnitus and hearing loss. He developed facial weakness after 5 years, and repeated imaging revealed tumor enlargement. Despite complete microsurgical excision, the tumor rapidly recurred locally and subsequently disseminated within the neuraxis. The patient died 1 year after tumor progression was detected. Histopathological analysis revealed a malignant spindle cell neoplasm with frequent mitotic figures. The presence of positive rhabdoid elements on immunohistochemical studies confirmed that it was a triton tumor. The authors review the relevant literature concerning the classification and management of malignant vestibular nerve tumors and discuss the implications of tumor progression after stereotactic radiosurgery.

Multiple radiation-induced intracranial lesions after treatment for pituitary adenoma. Case report

This 53-year-old man presented with a syncopal episode 31 years after undergoing craniotomy and external-beam radiation for a pituitary macroadenoma. A gadolinium-enhanced magnetic resonance (MR) image of the brain demonstrated a 2.5-cm enhancing mass in the right caudate region that had not been seen on previous studies. A stereotactically guided biopsy procedure was performed to obtain specimens from the mass, which were consistent with ependymoma. The MR image also revealed two additional lesions that appeared to be within the radiation fields: a right temporal meningioma and a left frontal cavernous malformation. A review of the literature found three previous reports in which ependymomas presented after radiation therapy.

Glioma occurrence after sellar irradiation: case report and review

OBJECTIVE

Tumor neogenesis is an uncommon but known consequence after therapeutic irradiation of the central nervous system. Causative agents for glioma induction remain unknown, but laboratory and clinical data suggest a possible role for radiation as a promotor. In the treatment of both pituitary adenomas and craniopharyngiomas, adjunctive conventional radiation therapy has long played a role.

CLINICAL PRESENTATION

This report details two cases in which patients received standard sellar irradiation for growth hormone-secreting pituitary adenomas and later were diagnosed with gliomas, after a latency period of 11 and 18 years, respectively. Additionally, a comprehensive review of the literature with 30 reports of gliomas developing after conventional radiation for treatment of pituitary adenomas and craniopharyngiomas is presented. The mean dose for craniopharyngiomas (n = 8) was 5800 cGy, with a mean latency of 11.5 years from initial diagnosis to the eventual discovery of the gliomas. The mean dose for the treatment of pituitary adenomas (n = 24) was 5300 cGy, with a mean latency of 10.4 years.

CONCLUSION

Typical features of the resulting gliomas included presentation in young patients, histologically high grades, and occurrence within the temporal lobe. A large proportion of gliomas were associated with growth hormone-secreting adenomas. This review assesses the implication of doses of conventional radiotherapy that were previously thought to be benign and concludes that although radiation-associated gliomas are uncommon, they represent a potentially devastating long-term risk. Based on this analysis, treatment of sellar tumors with conventional fractionated radiotherapy should be carefully considered and perhaps used primarily in those cases for which radiosurgery is not appropriate.

Radiation-induced sarcoma of the skull: report of two cases

The authors describe two cases of sarcomas of the skull following cranial irradiation in patients treated for other neoplasms, acute lymphatic leukemia, and astrocytoma, respectively. The patients (one man and one woman: mean age 24.5 years) developed sarcomas within the irradiated field after a mean latency period of 11.5 years. Histologically, the tumor proved to be a fibrosarcoma. Despite aggressive surgery and other therapy, the survival of the patients was short (10 and 8 months, respectively). The pathological and clinical aspects of this unusual complication are analyzed with reference to 41 cases taken from the world literature.

Multiple neoplasms following craniospinal irradiation for medulloblastoma in a patient with nevoid basal cell carcinoma syndrome. Case report

A 28-year-old man presented to the authors' hospital with multiple intracranial tumors. At 2 years of age, he had undergone resection of a medulloblastoma and received adjunctive craniospinal irradiation. Subsequently, he was diagnosed with nevoid basal cell carcinoma syndrome, Gorlin's syndrome. Since his first presentation, he has required surgery for multiple basal cell carcinomas, an osteochondroma of the rib, two meningiomas, a trigeminal schwannoma, and a pleomorphic liposarcoma, all of which arose within the radiation field. Despite this impressive list of benign and malignant neoplasms, the patient is relatively well and leads a normal life. The authors examine the relationships between Gorlin's syndrome and radiation therapy and the subsequent development of tumors.