Case Of Malignant Transformation Research Articles

Long-Term Outcome for Primary Papillomas of the Lacrimal Drainage System.

To report long-term outcomes after surgery for primary benign papillomas of the lacrimal drainage system. Retrospective review of patients with primary lacrimal drainage system papillomas, first seen between 1984 and 2021, but excluding lesions with sino-nasal origin or malignant histology. Patients were categorized by tumor histology (squamous, transitional, and mixed cell) and growth pattern (exophytic, endophytic, or mixed). Thirty patients (18 female; 60%) presented at a mean age of 46.1 years (12-79 years). Over an average follow-up of 10.4 years, 30% of patients experienced recurrence, with rates differing slightly by growth pattern: 25% for exophytic tumors and 40% for endophytic and mixed-pattern tumors (p = 0.431). The overall 5-year recurrence-free survival was 67% (± 9% standard error), this being slightly higher for exophytic lesions (75% ± 10%) as compared to 48% (± 19%) for tumors with an endophytic component (p = 0.370). No cases of malignant transformation were observed, and the tumor type at recurrence matched the initial diagnosis. Primary benign papillomas of the lacrimal drainage system have a long-term recurrence rate of about one-third, with a higher frequency in those exhibiting an endophytic growth pattern. The study highlights the importance of prolonged surveillance for recurrence, especially for endophytic and mixed growth pattern tumors, and for the potential to undergo malignant transformation. The results support the effectiveness of endoscopic surgical excision or laser thermos-ablation in managing recurrent lacrimal drainage system papillomas after dacryocystorhinostomy.

Incidence and clinical characteristics of pediatric ocular tumors in a Midwestern US population

To investigate the incidence and clinical characteristics of pediatric ocular tumors in a US Midwestern county population. Retrospective population-based cohort study of all Olmsted County, Minnesota, pediatric patients (<18 years old) diagnosed with any ocular neoplasm from January 1, 2006, to December 31, 2015. Subjects were identified via the Rochester Epidemiology Project, a record-linkage system that captures virtually all medical care provided in this county. Medical records were reviewed to confirm diagnoses. Age- and sex-adjusted incidence rates were calculated and adjusted to the 2010 Olmsted County, Minnesota, pediatric population. There were 87 incident pediatric ocular tumor diagnoses, yielding an overall age- and sex-adjusted incidence rate of 24.0 per 100,000 per year (95% CI, 19.0-29.1). Females accounted for 46 cases (53%) cases, and 62 (85%) were White. Incidence rate for ocular tumors overall did not differ by patient age (P = 0.08) or sex (P = 0.47). All tumors were benign lesions. The most frequent adnexal/orbital, ocular surface, and intraocular tumors were epidermal inclusion cyst in 18 (21%) cases, conjunctival nevus in 10 (12%), and choroidal nevus in 18 (21%), respectively. The mean follow-up duration was 25.5 months (range, 7 days to 138.6 months), and benign tumor growth occurred in one conjunctival nevus. There were no cases of malignant transformation. Pediatric ocular tumors were rare with an estimated incidence of approximately 1 in 4,200pediatric patients in Olmsted County, Minnesota. All lesions were benign, withbenign growth in only 1% of cases, and no tumors underwent malignant transformation.

Two Cases of Malignant Transformation in Crohn’s Disease with Perianal Involvement

Two Cases of Malignant Transformation in Crohn’s Disease with Perianal Involvement

A Rare Case of Paratesticular Cystadenoma with Ovarian Stroma Found by Scrotal Ultrasound on a Cirrhotic Patient with Elevated Alpha-fetoprotein

Abstract Introduction/Objective Paratesticular cystadenoma with ovarian stroma is a rare benign cyst-forming neoplasm with less than 10 cases reported in the literature. Typically, it presents in men aged 11 to 68 years (average 30) and is asymptomatic. The tumor is hypothesized to represent the efferent ductulus undergoing metaplastic change, the vestigial remnants of Mullerian duct, or mesothelium of the tunica vaginalis. Most tumors are considered benign, but a few cases of malignant transformation have been reported. Methods/Case Report We present a case of a 54-year-old male with a history of cirrhosis and elevated alpha-fetoprotein (17.85 ng/ML) who was found to have a paratesticular mass by scrotal ultrasound. Clinical history was obtained from review of electronic medical record. CD10 (Novocastra Clone 56C6) and progesterone receptor (PR) (Leica Clone 16) Immunoperoxidase stains were performed following the vendor recommendations. Surgical excision revealed a 0.6-cm polypoid nodule on tunica albuginea that was entirely submitted. Microscopically, the tumor was comprised of cystic spaces lined by cuboidal epithelium identical to that of the Fallopian tubes. There was a sparse spindle-shaped stroma underlying the epithelium similar to ovarian stroma. No nuclear atypia or mitosis was found. Immunoperoxidase stains showed the epithelium was positive for PR, and the stroma was positive for CD10. No evidence of germ cell tumor was identified. Results (if a Case Study enter NA) NA. Conclusion Characteristic histologic and immunophenotypic findings can aid in the diagnosis of paratesticular cystadenoma with ovarian stroma. Surgical resection for histological confirmation and long-term monitoring for the potential recurrence and metastatic spread are required.

What is the malignant transformation potential of oral lichen planus?

Data sources In this systematic review and meta-analysis, Medline, Scopus and Web of Science databases were searched using Medical Subject Headings (MeSH) to identify studies assessing the risk of malignant transformation in oral lichen planus (OLP).Study selection Observational studies published in English between 2003-2020 were independently assessed for inclusion by two blinded investigators.Data extraction and synthesis Data were extracted independently by two investigators followed by discussion to reach consensus. This included: study design and patient characteristics; length of follow-up; risk of bias; method of OLP diagnosis; oral squamous cell carcinoma (OSCC) risk factors; rate of malignant transformation; and individual characteristics of malignant transformation cases. Cases of malignant transformation in the included studies were only included in meta-analysis if: 1) OLP diagnosis met current diagnostic criteria; 2) OSCC developed in the same site as previously diagnosed OLP after at least six months' follow-up; 3) the patient had no history of systemic immunosuppressive therapy, head and neck malignancy, or organ transplantation. Risk of bias was assessed using the modified Newcastle-Ottawa scale, and meta-analysis was conducted to estimate overall risk of OLP malignant transformation using the DerSimonian and Laird method. Pooled univariate odds ratios (OR) for malignant transformation were calculated based on gender, smoking status, alcohol consumption, hepatitis C infection and OLP subtype.Results In total, 593 studies were identified after removal of duplicates and 33 studies were included for data extraction. The included sample comprised 12,838 patients with OLP, and 151 malignant transformation cases were reported in the included studies. The authors excluded 56 malignant transformation cases from the meta-analysis, most commonly because of the absence of pathological OLP diagnosis. Among included malignant transformation cases, the mean (SD) age was 58.1 (12.4) years, and 64% of the sample was female. Random-effects meta-analysis estimated an OLP malignant transformation rate of 0.2% (95%CI: 0.1-0.3%). Heterogeneity was low (I2 = 28.74%, p = 0.065). Malignant transformation was significantly higher among smokers (OR = 4.62, p = 0.001), alcohol consumers (OR = 3.22, p = 0.05), those with hepatitis C (OR = 3.77, p = 0.03) and atrophic or erosive OLP subtypes (OR = 2.70, p = 0.03). Gender was not associated with increased risk of malignant transformation.Conclusions The malignant transformation rate of OLP is likely to be lower than previously reported, possibly as a result of variable diagnostic criteria. Whilst encouraging, clinical vigilance remains necessary, as OLP does carry a small risk of malignant transformation. Smoking, alcohol use, hepatitis C infection and erosive or atrophic subtypes appear to have a greater rate of malignant transformation.

Tubal Endometriosis: From Bench to Bedside, A Scoping Review.

Tubal endometriosis (EM) refers to the detection of ectopic endometrial implants on tubes. It may cause a significant defect of the tubes, translating into dysmenorrhea, pelvic pain, and infertility. We aimed to evaluate the disease characteristics, prevalence, histopathological findings and genetic profile of patients with tubal EM. A thorough search of three electronic databases was performed for studies that presented outcomes of patients with tubal EM. Thirteen studies (four observational, seven case reports, two genetic) were considered eligible for inclusion. The prevalence of tubal EM ranged from 6.9% to 69%. The predominant symptoms for referral of patients were infertility and abdominal pain. Women of reproductive age underwent salpingectomy for the management of the disease. Only one case of malignant transformation was recorded in a 60-year-old patient. The prevalence of tubal EM ranges depending on the indication for surgery, the presence of concomitant pelvic EM and the type of diagnosis and treatment. Further, more extensive, larger studies are warranted to evaluate the impact of tubal EM in the progression and prognosis of EM, the effect of salpingectomy in the improvement of disease-related symptoms and to designate the group of patients that could benefit from risk-reducing salpingectomy based on the risk of developing ovarian malignancy.

Clinical behavior of advanced giant cell tumor: 15 years observation study in N.N. Blokhin National Medical Research Center of Oncology.

e23501 Background: Giant cell tumor of bone (GCT) is a relatively rare, benign but locally aggressive osteolytic skeletal neoplasm of young adults, most frequently occurs at the epiphysis of long bones. Distant metastases occur approximately 2-6% of cases most often to the lungs. However, pulmonary metastases do not carry the same connotation as metastases associated with malignant tumors, such as lung cancer or sarcoma. Rarely, GCT undergoes true malignant transformation. The aim of this study is to analyze the clinical behavior of advanced GCT during long-term observer in N.N. Blokhin National Medical Research Center of Oncology. Methods: We observed 51 advanced cases among 298 GCT from 2005 till 2020 in N.N. Blokhin National Medical Research Center of Oncology. Disease was histologically confirmed by a sarcoma pathologist. Patients underwent CT/MRI every 2 or 3 months of treatment and every 3, 6 or 12 months of follow up period. Treatment options were included atypical pulmonary resection, palliative surgery, chemotherapy with CAP or AI combination, interferon alfa or observation until progression. After 2013 prefer treatment option for advanced GCT was denosumab with once in 3 month’s regimen after 2 years monthly therapy. All patients received daily calcium and vitamin D supplement. Logistic regression was using for statistic analyzes. Results: Median follow-up was 45 months. The average age of patients was 34,8 years, and the women and men ratio was about 1,8:1. The most commonly affected sites were tibia (23,5%, 12/21), sacrum (17,6%), radius (13,7%) and femur (9,8%). According Campanacci classification G3 was the most commonly grade (90%). 46 (56%) cases were anatomically compounded due to tumor localization and 19 (37%) cases were primary disease. 18/298 (6%) cases were with pulmonary metastases. Surgery in history (p &lt; 0,001) and tumor localization in extremity (p &lt; 0,001) were significant for metastasis development. The primary malignant GCT observed in 1% (3/298) cases and 1 % cases of malignant transformation GCT into sarcoma. Only 1/51 (1,9%) death was observed in advanced GCT group. Complications ≥3 grade were observed only in pre-denosumab era. Conclusions: In this study we showed long-term observation of advanced GCT and evaluated significant factors for metastasis development. Surgeries in history and tumor localization were associated with higher risk of metastasis. Denosumab for advanced GCT is a choice of treatment, we wasn’t observed any cases of GCT malignant transformation during denosumab treatment. Quality of live was better in compare with pre-denosumab era. Further investigation of long term denosumab complications is awaited.

Epistaxis caused by nasal septum angioleiomyoma

BACKGROUND: Angioleiomyoma is an uncommon, benign tumour originating from vascular smooth muscle. Occurrence in the nasal cavity, especially the nasal septum, is rare with only 16 cases of nasal septal angioleiomyoma reported thus far. We present a new case of nasal septal angioleiomyoma. CASE PRESENTATION: 52-year-old female presented with a three-week history of persistent epistaxis and nasal obstruction. Physical examination revealed a right sided nasal mass originating from the septum. The tumour was endoscopically excised and sent for pathological evaluation which revealed the diagnosis of angioleiomyoma. The patient was followed for six months postoperati- vely and showed no evidence of lesion recurrence. CONCLUSIONS: Because nasal cavity angioleiomyoma recurrence has been reported due to incomplete tumour resection, wide marginal excision is necessary for successful treatment. There have been no cases of malignant transformation of nasal angiolei- omyomas; however, malignant transformation at other sites has been reported. For these reasons, it is important to adequately biopsy and remove angioleiomyoma lesions.

Malignant Transformation of Craniopharyngioma after Growth Hormone Replacement Therapy

Background: We present a rare case of malignant transformation of a craniopharyngioma in a patient who received growth hormone replacement therapy. Case Description: A 43-year-old male came to our department with a headache and visual disturbance and was admitted. Brain magnetic resonance imaging (MRI) revealed a giant tumor in the intra- and suprasellar region compressing the optic chiasma. Using a transcranial pterional approach, the tumor was removed as much as possible, with the residual mass removed later with a trans-sphenoidal approach. The initial histopathological diagnosis was adamantinomatous craniopharyngioma. Decompression of the optic chiasma was achieved and visual function improved, though residual tumor tissue remained in the parasellar region, without regrowth seen for more than 24 years. At the age of 67 years, the patient received growth hormone replacement therapy because of a deficiency, then 2 years later the residual tumor began to grow gradually. Trans-sphenoidal surgery was again performed to remove the growing tumor and histopathology results revealed an adamantinomatous craniopharyngioma with malignant transformation. Stereotactic radiation therapy was performed for the residual mass with a total dose of 60 Gy. Presently, 1 year later the patient has a stable condition, and the tumor remains controlled, while follow-up examinations are continuing. Conclusion: A craniopharyngioma may undergo malignant transformation with continuous exposure to administered growth hormone. Close follow-up and imaging examinations are necessary to detect a change, including tumor growth in such cases.

Fertility-sparing surgery and reproductive-outcomes in patients with borderline ovarian tumors

BackgroundBorderline ovarian tumors (BOT) are considered a biological category with increased epithelial proliferation and cellular atypia in the absence of invasive growth. Since BOT occur often in young patients fertility sparing surgery (FSS) is an important issue. With this study we aimed to evaluate risk factors for relapses and fertility of patients after FSS. MethodsPatients diagnosed with BOT and treated between 2000 and 2018 were included. External pathological review was done in all patients. FSS was performed after individual discussion and a complete surgical staging according to FIGO, without lymphadenectomy and with a waiver for preservation of uterus and one ovary. ResultsAmong 352 Patients 80.2% had FIGO I and 63.9% had a serous BOT. Eighteen patients (5.1%) relapsed and 4 cases of malignant transformation were reported (1.1%). One patient of the latter died, all others have no evidence of disease. The overall recurrence-rate was 1.1% in FIGO-Stage I and 25.5% in FIGO III-IV (HR = 27; 95%-CI 7.7–95; p ≤.001). 95 patients underwent FSS. Thirteen (13.7%) of these patients relapsed, all as BOT. In multivariate analysis FIGO stages II-IV (HR = 27; 95%-CI: 8.1–102; p ≤.001) and FSS (HR = 12; 95%-CI: 2.9–47; p = .001) remained significant risk factors for recurrent disease. Pregnancy rate among forty-one patients attempting to conceive was 82.9%. 29 patients experienced at least one life-birth, in total 38 life-births were reported. ConclusionFSS in stage I is a safe procedure and life-birth-rates after FSS are high. More advanced FIGO stages have to be discussed individually and relapse rates have to be weighed against FSS. A central review of pathology, as we performed routinely, is mandatory and may have contributed to our low rate of invasive relapses.

Trichofolliculoma of the eyelid: systematic review

BackgroundTrichofolliculoma of the eyelid and periorbital region remains is rare, and there is limited evidence regarding surgical management, clinical and histological margins, and recurrence rate.ObjectivesWe performed a systematic review of cases to date on diagnosis and management outcomes of eyelid trichofolliculoma.MethodsElectronic databases were searched for cases reported on trichofolliculoma of the eyelid. The authors extracted and collated data from these studies, and outcomes were summarized descriptively.ResultsOne hundred twenty citations were identified from database searching. The authors also report a case of eyelid trichofolliculoma. Fifteen studies reporting 19 cases of eyelid trichofolliculoma were finally included. Eighteen out of 19 (94.7%) cases were treated with surgical excision. Of 5 cases which were followed up over an average of 2 years, there was only 1 case of recurrence requiring wedge resection.ConclusionsRecurrence rate in patients with eyelid trichofolliculoma excised with satisfactory margins appears to be low, and no cases of malignant transformation have been reported.

First report of pulmonary sclerosing pneomucytoma with malignant transformation in both cuboidal surface cells and stromal round cells: a case report

BackgroundPulmonary sclerosing pneumocytoma (PSP) is a rare benign tumor. Although lymph node metastasis has been reported, it is still considered benign. No malignant transformation has been reported. This is the first case of malignant transformation of both cuboidal surface cells and stromal round cells.Case presentationA 64-year-old male had been complaining of intermittent hemoptysis several times per day for eight months. Chest computed tomography scan showed parenchymal infiltration with cystic lesion in the right lower lobe accompanied by enlarged right hilar lymph nodes. Lobectomy and systemic lymph node dissection was performed.On grossly pathological examination, the lesion was 50 mm from the bronchial stump. It was a mixture of both cystic and solid components and 30 mm * 20 mm in size with unclear border. Microscopically, the cuboidal surface cells transformed to adenocarcinoma. The stromal round cells also had a malignant transformation. The Ki-67 proliferation index in malignant cuboidal surface cells and stromal round cells were 70 and 55%, respectively. Furthermore, E-cadherin was negative in primary tumor but positive in metastatic lymph node, which suggested that the mesenchymal to epithelial transition may play an important role in lymph node metastasis.ConclusionsTo our knowledge, we present the first case of malignant transformation of both cuboidal surface cells and stromal round cells in PSP. The process of mesenchymal to epithelial transition may play an important role in lymph node metastasis.

A molecular study of synovial chondromatosis.

Synovial chondromatosis (SC) is a rare benign cartilaginous neoplasm in which recurrent fibronectin 1 (FN1) and activin receptor 2A (ACVR2A) gene rearrangements have been recently reported. Triggered by a case of malignant transformation in SC (synovial chondrosarcoma) showing a novel KMT2A-BCOR gene fusion by targeted RNA sequencing, we sought to evaluate the molecular abnormalities in a cohort of 27 SC cases using a combined methodology of fluorescence in situ hybridization (FISH) and/or targeted RNA sequencing. Results showed that FN1 and /or ACVR2A gene rearrangements were noted in 18 cases (67%), with an FN1-ACVR2A fusion being confirmed in 15 (56%) cases. Two cases showed only FN1 gene rearrangement, without other abnormalities. A novel FN1-NFATc2 gene fusion was noted in one case by RNA sequencing. The remaining nine cases showed no abnormalities in FN1 and ACVR2A genes. No additional cases showed BCOR gene alterations. In conclusion, this study confirms that FN1-ACVR2A fusion is the leading pathogenetic event in SC, at even higher frequency than previously reported. FISH methodology emerges as an appropriate tool in the identification of FN1 and ACVR2A gene abnormalities, which can be used in challenging cases. Further studies are needed to determine the recurrent potential of BCOR abnormalities in this disease.

A National Survey of Umbilical Endometriosis in Japan

To identify the clinical presentation, diagnostic evaluation, operative or medical management, and postoperative recurrence of umbilical endometriosis. A retrospective national survey. Obstetrics and Gynecology and Plastic Surgery Departments at a teaching hospital in Japan. Patients with umbilical endometriosis or malignant transformation. A national survey was conducted to identify and evaluate cases of umbilical endometriosis or malignant transformation documented between 2006 and 2016. The following were evaluated for each patient: age at diagnosis, body mass index, medical history, presence of extragenital endometriosis, surgical history, symptoms, imaging modalities, surgical therapy, hormonal therapy, follow-up period, postoperative recurrence, and time to recurrence. Ninety-six patients were identified with pathologically diagnosed benign umbilical endometriosis. The patients frequently had swelling (86.5%), pain (81.3%), or bleeding (44.8%) in the umbilicus. Sensitivity was 87.1% for physical examination, 76.5% for transabdominal ultrasonography, 75.6% for computed tomography, and 81.8% for magnetic resonance imaging. The cumulative recurrence rate was 1.34% at 6 months, 6.35% at 12 months, and 6.35% at 60 months after surgery. Importantly, there was no recurrence after wide resection including of the peritoneum (0 of 37 cases). The efficacy of dienogest (an oral progestin), gonadotropin-releasing hormone agonists, and oral contraceptives was 91.7%, 81.8%, and 57.1%, respectively. Finally, 2 cases of malignant transformation were identified. There was a low recurrence rate following surgery, and hormonal treatment is an option, although the current findings suggest surgical therapy as the first choice of treatment for umbilical endometriosis.

Cystic lymphangioma of the arm

Abstract Cystic Lymphangiomas (CL) is an uncommun benign neoplasma wich frequently occurs to young adults. The lymphatic system can be developed by two theories: the centripetal and centrifugal theories. This study aims to present to a case of giant CL, because of its atypical location. A 3 years old girl consulted for a swelling of the lower 1/3 of the right arm, discovered since the age of 1 year. Complete surgical excision was performed with an external approach of the right arm. The contribution of imaging in particular MRI and the interest of a complete surgical excision which allows diagnosis and surgical treatment. However, a few local recurrences, fistula malformation or infection have been reported. No case of malignant transformation has been reported in the literature.

Surgical outcomes of sinonasal inverted papilloma: a 17 year review

IntroductionInverted papillomas represent one of the most common benign neoplasic lesions located in the sinonasal tract. Owing to the local erosive behavior, tendency to recur and the potential for malignant transformation, surgical management of inverted papillomas is often challenging. ObjectiveThis study aimed to analyze the surgical outcomes of patients with inverted papillomas, according to the Krouse staging and the different surgical approaches. MethodsRetrospective study of patients diagnosed with sinonasal inverted papillomas who underwent surgical treatment between 2000 and 2016 at a tertiary referral hospital. Cases with follow-up less than 12 months were excluded. The rate and the time of recurrence were the main outcomes. Values of p<0.05 were considered statistically significant. ResultsThirty-six cases with mean age of 60 years, predominantly male (72%), were included. The follow-up period ranged from 1 to 16 years, with an average of 4.5 years. Krouse T1 Stage corresponded to 11.1%; T2 occurred in 50% of cases; while T3 and T4 Stages accounted for 30.6% and 8.3% of patients, respectively. Most cases were approached by an endoscopic technique alone (83.3%), with a recurrence rate of 13.3%. Patients treated via a combined or open approach revealed a recurrence of 16.7%. No differences in the recurrence rate were reported when comparing endoscopic surgery with the open or combined techniques. Krouse Stage T3 had a significant association with inverted papillomas recurrence (p=0.023). All inverted papilloma relapses occurred up to 2 years post-operatively. One case of malignant transformation was recorded (2.7%). ConclusionEndoscopic surgery did not increase the recurrence rates and can be a safe and efficient alternative to open or combined techniques. The recurrence of inverted papillomas seem to be related to the persistence of the disease and tend to occur early after primary surgery. Krouse T3 Stages may be associated with a higher recurrence of inverted papillomas.

Pleomorphic Adenoma of the Submandibular Gland: A Case Report

Salivary gland tumours are relatively rare and constitute about 3-4% of head and neck tumours. Most of the tumours arise from parotid glands. Submandibular gland tumours are very rare. Pleomorphic adenoma of the submandibular gland is exceedingly rare tumour. Very few studies have been reported in the literature that is exclusively conducted on pleomorphic adenoma affecting submandibular gland. Patients usually present with a slow growing, painless and mobile mass without any other associated symptoms. Radiologic studies are usually unable to differentiate benign from malignant tumours in most cases. Recurrence is rare with complete en bloc excision of the tumour along with submandibular gland. Prognosis is excellent except for the rare cases of malignant transformation. This paper describes a case of pleomorphic adenoma affecting submandibular gland with brief review of current literature on submandibular gland tumours. Keywords: pleomorphic adenoma; salivary gland; submandibular gland tumours.

A Case of Malignant Transformation in a Sporadic Juvenile Polyp in the Cecum, Which Caused Intussusception in a Seven-Year Old Boy

A Case of Malignant Transformation in a Sporadic Juvenile Polyp in the Cecum, Which Caused Intussusception in a Seven-Year Old Boy

The role of adjuvant radiotherapy in management of recurrent pleomorphic adenoma of the parotid gland: a systematic review.

Recurrent pleomorphic adenoma poses a significant treatment challenge, considering its propensity for further recurrence and potential for malignant transformation. The role of adjuvant radiotherapy in its management is widely debated. The aim of this study was to determine whether adjuvant radiotherapy is more effective than surgical resection alone in patients with recurrent pleomorphic adenoma of the parotid gland, in terms of further recurrence, malignant transformation and treatment-related complications. Using PRISMA guidelines, a systematic review comparing adjuvant radiotherapy with surgery alone in the treatment of recurrent pleomorphic adenoma was conducted. Pubmed, OVID, EBSCO, Embase, The Cochrane Library, SCOPUS and OpenGrey databases from 1988 to 2018 were searched. Quality analysis was carried out using the Newcastle-Ottawa Scale and narrative synthesis used to summarise results. Of 891 records screened, eight studies were included, assessing 366 participants. Two noted a benefit of adjuvant radiotherapy in reducing further recurrence. The remainder did not show significant benefit, although four showed a trend towards lower rates. Only one case of malignant transformation was identified in a patient not irradiated. Similar rates of facial nerve dysfunction were identified between groups. The available evidence suggests that adjuvant radiotherapy reduces recurrence rates in patients with recurrent pleomorphic adenoma and certain adverse prognostic factors. While it appears not to have significant adverse effects, given the lack of prospective evidence, we recommend careful use in patients at high risk of further recurrence and further research in the form of well-designed randomised controlled trials.

GP.05 The risk of malignancy after stereotactic radiosurgery

Background: A major concern of patients undergoing Gamma Knife radiosurgery (GKS) for benign tumors and other conditions is the risk of a separate secondary malignancy or malignant -transformation. The incidence of radiosurgery-associated malignancy based on long-term follow-up remains unknown. Methods: We conducted a population-based cohort study to estimate the incidence rate of both malignant transformation and a separate radiation-associated malignancy in patients undergoing GKS from 1987 to 2016 at 5 centers. Results: 11 527 patients underwent radiosurgery for meningioma (n=3261), arteriovenous malformation (n=2868), trigeminal neuralgia (n=1982), vestibular schwannoma (n=1957), pituitary adenoma (n=1193), other (n=266). The follow-up time ranged from 0.3 to 23.8 years. Four cases of malignant transformation and 3 new malignant brain tumors were reported, two of which were not within the irradiated field. The incidence of malignant transformation was 6.6 per 100 000 patient-years and of new malignancy, either locally or distant, was 5 in 100 000 patient-years. These risks are not higher than the Central Brain Tumor Registry of the United States derived annual incidence rate of all primary malignant CNS tumors of 7.15 per 100 000. Conclusions: Physicians can safely counsel patients that the risk of malignancy after stereotactic radiosurgery remains extremely low, even at long-term follow-up of greater than 10 years.