Radiation Therapy-Induced Fibrous Histiocytoma, Mimicking Local Recurrence and Detected by 18 F-FDG PET/CT in a Patient With Breast Cancer.

ABSTRACT: A 76-year-old woman was diagnosed breast carcinoma and treated with breast-conserving surgery and chemoradiotherapy. A year after the treatment completion, restaging 18 F-FDG PET/CT scan detected no any pathological finding. However, due to a lesion detected during physical examination on the right thoracic wall adjacent to the primary tumor bed, 18 F-FDG PET/CT imaging was performed 9 months later for restaging. Highly intense FDG uptake was detected in an approximately 1-cm nodular lesion, and metastasis was reported as suspicious, and histopathological confirmation was recommended. Excision was performed and pathological examination diagnosed benign cellular fibrous histiocytoma.

Estimation of maternal and foetal risk of radiation-induced cancer from a survey of computed tomography pulmonary angiography and ventilation/perfusion lung scanning for diagnosing pulmonary embolism during pregnancy.

INTRODUCTION: While there are many papers on maternal and foetal radiation doses from computed tomography pulmonary angiography (CTPA) and ventilation/perfusion (V/Q) lung scanning examinations for diagnosing pulmonary embolism in pregnant patients, few have used clinical data to examine the patient lifetime attributable risk (LAR) of different cancer types. This paper aims to estimate the cancer risk from maternal radiation doses from CTPA and V/Q examinations and associated foetal doses. METHODS: Dosimetric data were determined for 267 pregnant patients who received CTPA and/or V/Q examinations over 8 years. Organ and foetal doses were determined using software allowing patient size variations for CTPA and using two different activity-to-organ dose conversion methods for V/Q scans. The LAR of cancer incidence was estimated using International Commission on Radiological Protection (ICRP) modelling including estimates of detriment. RESULTS: Estimated total cancer incidence was 23 and 22 cases per 100,000 for CTPA and V/Q examinations, respectively, with detriment estimates of 18 and 20 cases. Cancer incidence was evenly divided between lung and breast cancer for CTPA with lung cancer being 80% of all cancer for V/Q. The median foetal doses were 0.03 mSv for CTPA and 0.29 mSv for V/Q. Significant differences in estimated foetal dose for V/Q scans were obtained by the two different methods used. The differences in dose between the modes of CTPA scan acquisition highlight the importance of optimisation. CONCLUSION: Maternal cancer incidence and detriment were remarkably similar for each examination. Optimisation of examinations is critical for low-dose outcomes, particularly for CTPA examination.

Radiation-associated angiosarcoma of the breast: analysis of diagnostic tools in a registry-based population.

BACKGROUND: Radiation-associated angiosarcoma of the breast (RAASB) is a serious late consequence caused by breast cancer treatment. Initial symptoms are often inconspicuous, thus contributing to diagnostic delay. Most previous studies of the diagnostic aspects of RAASB are case reports. PURPOSE: To perform a complete review of the imaging findings and biopsy methods in a nationwide RAASB cohort. MATERIAL AND METHODS: RAASB patients were identified from a national cancer registry and additional patients were included from our hospital. All available information from imaging (mammogram [MGR], ultrasound [US], magnetic resonance imaging [MRI], and computed tomography [CT]) and biopsies was reviewed. The sensitivity of imaging and biopsy methods for detection of RAASB was calculated. RESULTS: Fifty-eight patients with RAASB were found. Fourteen MGR, 30 US, 24 MRI, and 25 CT studies were available for evaluation. The sensitivity of MGR, US, MRI, and CT for detection of RAASB was 43%, 50%, 92%, and 84%, respectively. Superior sensitivity was demonstrated for punch biopsy (84%) and incisional biopsy (93%) compared to fine-needle aspiration cytology (0%) and core needle biopsy (18%). CONCLUSION: MRI and CT have comparable sensitivity for detection of RAASB, while MGR and US are unreliable. However, negative findings in MRI or CT must be interpreted with caution. Punch biopsy and incisional biopsy are the preferred biopsy methods.

Radiation-Induced Meningioma in a Case of Medulloblastoma Treated 11 Years Ago-Detected on 68Ga-DOTANOC PET/CT.

ABSTRACT: Medulloblastomas, especially the sonic hedgehog subgroup, are treated aggressively with surgery and chemoradiotherapy, as they are associated with high local site recurrence rate and poor overall survival. Radiation-induced meningioma is the most common delayed complication of craniospinal irradiation. This needs to be differentiated from meningeal or ependymal metastases as the later need aggressive management. We report one such rare case, in a patient who completed treatment for medulloblastoma 11 years ago, was in remission, and now presented with dural-based lesions.

Are radiation-induced cavernomas clinically relevant findings? Results from long-term follow-up with brain magnetic resonance imaging of childhood cancer survivors.

INTRODUCTION: Radiation-induced cavernomas (RIC) after cranial radiotherapy have an unknown risk of hemorrhage. Zabramski magnetic resonance imaging (MRI) classification is touted as being able to indicate non-radiation-induced cavernomas hemorrhage risk. The aim of our study was to assess the hemorrhage risk of RIC during long-term follow-up of childhood cancer survivors based on brain MRI examinations. PATIENTS AND METHODS: We analyzed retrospectively long-term follow-up data of 36 childhood cancer survivors after initial diagnosis with acute leukemia (n = 18) or brain tumor (n = 18), all treated with cranial radiotherapy. Detected RIC in long-term follow-up brain MRI (1.5 or 3 Tesla) were classified following the Zabramski MRI classification and were categorized into "high" (Zabramski type I, II or V) or "low" (type III or IV) risk of hemorrhage. RESULTS: 18 patients (50%) showed RIC with a significant relation to the original tumor entity (p = 0.023) and the cumulative radiation dose to the brain (p = 0.016): all 9 childhood cancer survivors diagnosed with medulloblastoma developed RIC. We classified RIC in only 3/36 childhood cancer survivors (8%) (1 patient with acute lymphoblastic leukemia [Zabramski type II] and 2 patients with medulloblastoma [type I and type II]) as high risk for hemorrhage, the remaining RIC were classified as Zabramski type IV with low risk for hemorrhage. None of the childhood cancer survivors with RIC showed symptomatic hemorrhages. CONCLUSIONS: RIC are common late effects in childhood cancer survivors treated with cranial radiotherapy affecting half of these patients. However, only a few RIC (occurring in 8% of all reviewed childhood cancer survivors) were classified as high risk for hemorrhage and none of the childhood cancer survivors with RIC developed symptomatic hemorrhages. Thus, we conclude that RIC are low-risk findings in brain MRI and the course is mainly benign.

Microsurgical Resection of Radiation-Induced Cervical Spinal Intradural Extramedullary Meningioma: Dural Splitting Resection.

Spinal meningiomas constitute 10% of all meningiomas. They most commonly rise in the thoracic spine and are most common in middle aged women; symptoms include progressive myelopathy.1,2 Radiation induced/radiotherapy-associated cranial meningiomas are well described with aggressive behavior; however, radiation-induced spinal meningiomas are extremely rare in the literature.3-7 Our patient had a history of Hodgkin lymphoma treated with neck radiation, and thyroid cancer treated with radioactive iodine/thyroidectomy. He presented with neck pain and myelopathy from a large intradural, extramedullary tumor compressing the spinal cord (C3-C5). He had a prevertebral phlegmon that was resolved with antibiotics prior to surgery. Intraoperative neurophysiological electrodes were placed for somatosensory-evoked potential and motor-evoked potential monitoring. C3-C5 bilateral laminectomies were performed (Video 1); dura was incised over the tumor. Tumor attachments to the dura were coagulated and divided. The tumor was dissected microsurgically from the spinal cord and nerve roots. The dural layer involved by the tumor was split and resected from the uninvolved dura, achieving tumor resection. Postoperatively, the patient's myelopathy resolved. He has been followed for a 1 year now with mangetic resonance imaging scans of the cervical spine ± contrast every 6 months. To our knowledge, this is the first operative video describing resection of a spinal meningioma, which happens to be radiation-induced, using a dural splitting technique to achieve better resection and prevent tumor recurrence. The alternative treatment would be to leaving the inner layer of dura, coagulation, or excising both layers and performing duraplasty. Both alternative options, however, would increase the risk of recurrence and spinal fluid leak. Cervical spine meningiomas with spinal cord compression and myelopathy should be resected to prevent further neurological decline. Dural splitting can be utilized to achieve "radical" tumor resection to prevent recurrence, which is particularly important if the tumor is aggressive and recurrent, as is the case in radiation-induced/radiotherapy-associated meningiomas. Upon dural closure, we applied autologous fat tissue along with fibrin glue to avoid spinal fluid leak as we published earlier.8 The patient consented to the procedure and publication of his image.

Radiation-induced occult insufficiency fracture or bone metastasis after radiotherapy for cervical cancer? The nomogram based on quantitative apparent diffusion coefficients for discrimination.

BACKGROUND: Radiation-induced insufficiency fractures (IF) is frequently occult without fracture line, which may be mistaken as metastasis. Quantitative apparent diffusion coefficient (ADC) shows potential value for characterization of benign and malignant bone marrow diseases. The purpose of this study was to develop a nomogram based on multi-parametric ADCs in the differntiation of occult IF from bone metastasis after radiotherapy (RT) for cervical cancer. METHODS: This study included forty-seven patients with cervical cancer that showed emerging new bone lesions in RT field during the follow-up. Multi-parametric quantitative ADC values were measured for each lesion by manually setting region of interests (ROIs) on ADC maps, and the ROIs were copied to adjacent normal muscle and bone marrow. Six parameters were calculated, including ADCmean, ADCmin, ADCmax, ADCstd, ADCmean ratio (lesion/normal bone) and ADCmean ratio (lesion/muscle). For univariate analysis, receiver operating characteristic curve (ROC) analysis was performed to assess the performance. For combined diagnosis, a nomogram model was developed by using a multivariate logistic regression analysis. RESULTS: A total of 75 bone lesions were identified, including 48 occult IFs and 27 bone metastases. There were significant differences in the six ADC parameters between occult IFs and bone metastases (p < 0.05), the ADC ratio (lesion/ muscle) showed an optimal diagnostic efficacy, with an area under ROC (AUC) of 0.887, the sensitivity of 95.8%, the specificity of 81.5%, respectively. Regarding combined diagnosis, ADCstd and ADCmean ratio (lesion/muscle) were identified as independent factors and were selected to generate a nomogram model. The nomogram model showed a better performance, yielded an AUC of 0.92, the sensitivity of 91.7%, the specificity of 96.3%, positive predictive value (PPV) of 97.8% and negative predictive value (NPV) of 86.7%, respectively. CONCLUSIONS: Multi-parametric ADC values demonstrate potential value for differentiating occult IFs from bone metastasis, a nomogram based on the combination of ADCstd and ADCmean ratio (lesion/muscle) may provide an improved classification performance.

Metabolic Evolution of Brain Metastasis After Stereotactic Radiosurgery: Mismatch Between F-DOPA and FDG PET.

The differentiation between radiation-induced changes and tumor recurrence is a major pitfall of magnetic resonance imaging, which can be overcome by the use of PET. Although amino-acid PET tracers showed several advantages over F-fluorodeoxyglucose in neurooncology, studies comparing these 2 types of radiopharmaceuticals in previously irradiated brain metastases are lacking. Here, we demonstrated a mismatch between 3,4-dihydroxy-6-[F]-fluoro-L-phenylalanine (F-DOPA) and FDG in the first report of a previously irradiated brain metastasis undergoing a longitudinal evaluation by sequential double tracer PET imaging.

Thyroid tumor surveillance using ultrasound in childhood cancer survivors.

BACKGROUND: The optimal method for thyroid cancer screening in childhood cancer survivors (CCSs) who received radiation involving the thyroid gland is still debated. We describe a case series of ultrasound surveillance for thyroid tumor in CCSs in our institute. METHODS: We conducted thyroid tumor surveillance for CCSs with a history of radiation therapy involving the thyroid. The basic screening method was palpation. Thyroid ultrasound was also performed for patients who agreed after its benefits and risks were explained to them. We surveyed CCSs who visited the long-term follow-up outpatient clinic in our institution between October 2014 and September 2018. RESULTS: Of 82 CCSs who visited our institution during the study period, 44 were eligible for inclusion. None had a mass identified by palpation. Thyroid ultrasound was performed in 39 CCSs, and we identified thyroid nodules in 27. Four patients had a nodule with malignant echo features. Two of these cases received biopsies, and one patient was ultimately diagnosed with an early stage thyroid carcinoma. CONCLUSIONS: Childhood cancer survivors irradiated in the thyroid had a higher prevalence of thyroid nodules than the general population. Ultrasound screening contributed to early detection of impalpable thyroid cancer and enabled us to perform minimal surgery. Thus, ultrasound appears to be a useful option for secondary thyroid cancer screening. The thyroid tumor surveillance modality should be considered according to the individual case, and the patient must receive a clear explanation of the benefits and risks. These results could help doctors consider how to screen for secondary thyroid cancer.

Image optimization and reduction of radiation dose in CT of the paranasal sinuses.

INTRODUCTION: Due to use of ionization radiation in the computed tomography (CT), optimal parameters should be used to reduce the risk of incidence of secondary cancers in patients who are constantly exposed to x-rays. To reduce the dose delivered to patients in each scan, CT technologists can change the image acquisition parameters. However, this reduces image quality. The present study aimed to optimize and reduce radiation dose in a CT of the paranasal sinuses while minimizing deterioration of image quality. METHODS: In this study patients were divided in two groups: Group A was scanned axially and coronally using default parameters, while Group B was scanned axially and coronally using new parameters. Common CT dose descriptors including weighted computed tomography dose index (CTDIw), volumetric CTDI (CTDIvol), dose length product (DLP), effective dose (ED) and image noise were measured for each group. The patients' organ doses were estimated using the ImPACT CT patient Dosimetry Calculator. The tube voltage, tube current, pitch, rotation time, and other parameters were then reduced and optimized. After reconstruction and analysis, all of the images were of good diagnostic quality in both groups Results: Using the new parameters, good agreement was found between the direct and reconstructed images. The CT parameters were reduced by the following proportions: kVp-16.6%, mA-75%, rotation time-20%, and mAs-80%. However, these reductions did not obscure any anatomical landmarks. These parameters reduced the CTDIw, CTDIvol and DLP by 88.2%, 91.3%, and 91.3% respectively. CONCLUSION: The results suggest that the use of a Bone algorithm reduces the total amount of radiation used during CT of the sinuses. We recommend using these parameters in children, in the evaluation of facial trauma, and in emergency CT of the paranasal sinuses.

Radiation-Induced Meningiomas: A Series of Four Consecutive Patients and a Review of Literature.

AIM: To assess the clinical outcomes of treatment for radiation-induced meningiomas. MATERIAL AND METHODS: Medical records were retrospectively reviewed for all cranial meningioma cases that were diagnosed and/or underwent surgery at our hospital from 2009 to 2016. All radiation-associated meningioma patients constituted the core sample for this study. RESULTS: This series included one female and three male patients, with a mean age of 47.3 ± 16.3 years. The mean preoperative course was < 3 months. The most common symptom was headache (100%) and three patients had alopecia and thin scalp skin. The mean of the age at which they underwent radiotherapy was 18.5 ± 13.7 years. The mean latency period was 19.2 ± 7.4 years. Initial malignancies included two patients with desmoplastic medulloblastomas (13-year-old female, 65 Gy), (11-year-old male, 54 Gy) and a patient with grade II oligodendroglioma treated with 30 Gy. A male patient received low-dose radiotherapy for chronic otitis at 10 years old. Histopathological examinations revealed the following: 1) fibroblastic-grade I, Ki-67 2%-3%, 25.5 years latency; cerebellopontine angle, 2) atypical meningioma grade II, Ki-67 8%, 21 years, frontal; and 3) transitional grade I, Ki-67 3%-4%, 11 years, frontal. The fourth patient had three radiation-induced meningiomas and 27 radiation-induced cavernomas, and was treated using a gamma knife. The mean follow-up period was 34.8 ± 39.4 months. One patient had rhinorrhea and another experienced a cerebrospinal fluid fistula. Both underwent an additional operation. The former died because of meningitis on postoperative day 31. CONCLUSION: Most radiation-induced meningiomas are low-grade, but they have a high trend of recurrence. Close follow-up and yearly magnetic resonance imaging would minimize the morbidity rate. To reduce fatal complications, surgery should be planned in conjunction with plastic surgeons.

Investigation of thyroid cancer cases that were not detected in the Thyroid Ultrasound Examination program of the Fukushima Health Management Survey but diagnosed at Fukushima Medical University Hospital.

The Great East Japan Earthquake, which occurred on March 11, 2011, and its subsequent Fukushima Daiichi Nuclear Power Plant accident, prompted implementation of the Thyroid Ultrasound Examination (TUE) program as a part of the Fukushima Health Management Survey. The purpose of this program is to support residents of Fukushima Prefecture, and to analyze the health effects of the released radionuclides. Regardless of relatively high participation rates and a well-planned diagnostic flow, it is conceivable that not all thyroid cancer cases can be detected by the TUE program. The aims of the present study were to identify and characterize these "outside" cases, targeting patients at Fukushima Medical University (FMU) Hospital. As of June 30, 2017, we have successfully identified 11 outside cases. These corresponded to 5.7% of the 194 subjects who were identified as having thyroid cancer or suspected thyroid cancer in the TUE program. Although the outside subjects of other institutes were not investigated, the present study may have identified the majority of outside subjects in Japan, considering that FMU Hospital treats a large number of thyroid cancer subjects. Furthermore, the characteristics of the 11 subjects were not different from those of the subjects identified in the TUE program. These findings confirm that the TUE program was able to identify subjects of thyroid cancer adequately and sufficiently.

Imaging Soft-tissue Sarcomas of the Head and Neck: A Tertiary Soft-tissue Sarcoma Unit Experience.

BACKGROUND/AIM: To describe imaging features of head and neck soft-tissue sarcomas. PATIENTS AND METHODS: Patients with a diagnosis of head and neck sarcoma between 2011 and 2015 were reviewed. RESULTS: There were a total of 62 patients (24 female; median age=60 years). Most common sarcomas were angiosarcoma, undifferentiated pleomorphic sarcoma and sarcoma not otherwise specified. They were most commonly located in cranial and neck superficial soft tissues. Average tumour size at presentation was 45 mm. One patient had metastasis at presentation (rhabdomyosarcoma); two had nodal disease (rhabdomyosarcoma and angiosarcoma) and two tumours contained calcification (chondrosarcoma and synovial sarcoma). Four arose after prior radiotherapy. CONCLUSION: Unlike the more common diagnosis of squamous cell carcinoma, the majority of head and neck sarcomas present as large, solitary, superficial masses without lymph node enlargement. Identification of these features on imaging should raise suspicion of a sarcoma diagnosis, particularly in the setting of previous irradiation or genetic susceptibility.

Association between the detection rate of thyroid cancer and the external radiation dose-rate after the nuclear power plant accidents in Fukushima, Japan.

A thyroid cancer ultrasonography screening for all residents 18 years old or younger living in the Fukushima prefecture started in October 2011 to investigate the possible effect of the radiological contamination after the Fukushima Daiichi Nuclear Power Plant accidents as of March 12 to 15, 2011. Thyroid cancer in 184 cases was reported by February 2017. The question arises to which extent those cancer cases are a biological consequence of the radiation exposure or an artefactual result of the intense screening of a large population.Experiences with the Chernobyl accident suggest that the external dose may be considered a valid surrogate for the internal dose of the thyroid gland. We, therefore, calculated the average external effective dose-rate (µSv/h) for the 59 municipalities of the Fukushima prefecture based on published data of air and soil radiation. We further determined the municipality-specific absolute numbers of thyroid cancers found by each of the two screening rounds in the corresponding municipality-specific exposed person-time observed. A possible association between the radiation exposure and the thyroid cancer detection rate was analyzed with Poisson regression assuming Poisson distributed thyroid cancer cases in the exposed person-time observed per municipality.The target populations consisted of 367,674 and 381,286 children and adolescents for the 1st and the 2nd screening rounds, respectively. In the 1st screening, 300,476 persons participated and 270,489 in the 2nd round. From October 2011 to March 2016, a total of 184 cancer cases were found in 1,079,786 person-years counted from the onset of the exposure to the corresponding examination periods in the municipalities. A significant association between the external effective dose-rate and the thyroid cancer detection rate exists: detection rate ratio (DRR) per µSv/h 1.065 (1.013, 1.119). Restricting the analysis to the 53 municipalities that received less than 2 µSv/h, and which represent 176 of the total 184 cancer cases, the association appears to be considerably stronger: DRR per µSv/h 1.555 (1.096, 2.206).The average radiation dose-rates in the 59 municipalities of the Fukushima prefecture in June 2011 and the corresponding thyroid cancer detection rates in the period October 2011 to March 2016 show statistically significant relationships.

Radiation-Induced Sarcoma on 18F-FDG PET/CT After Treatment of Gorham-Stout Disease of the Maxilla.

Gorham-Stout disease is a rare disorder characterized by proliferation of lymphatic and vascular channels within bone resulting in osteolysis. A 53-year-old man with Gorham-Stout disease involving the left maxilla underwent previous treatment including radiation therapy and intralesional chemotherapeutic injections. He later presented with anemia, facial pain, weight loss, and nasal cavity hemorrhage. CT imaging demonstrated a mass centered within the right maxillary sinus with locoregional involvement. PET/CT showed prominent FDG activity involving the mass centered in the right maxillary sinus with low-grade avidity involving the contralateral maxilla in regions of treated Gorham-Stout disease. Biopsy of the mass confirmed radiation-induced sarcoma.

Incidental Detection of a Radiation-Induced Soft-Tissue Sarcoma on 68Ga-PSMA PET/CT in a Patient Previously Treated for Prostate Cancer.

Radiation-induced sarcoma is a rare complication of radiation therapy. We describe the incidental detection of a radiation-induced undifferentiated soft-tissue sarcoma with increased uptake on Ga-labeled prostate-specific membrane antigen (PSMA) PET/CT in a prostate cancer patient previously treated with surgery and external-beam radiotherapy. Results were confirmed by histological analysis. Ga-PSMA is known to bind not only to PSMA-expressing prostate cancer cells but also to the neovasculature of various other solid tumors. A careful Ga-PSMA PET/CT review of previously irradiated areas is warranted so as not to miss radiation-induced sarcoma in prostate cancer patients.