Imaging surveillance of gastrointestinal stromal tumour: current recommendation by National Comprehensive Cancer Network and European Society of Medical Oncology-European Reference Network for rare adult solid cancers.

Imaging plays an active role in the surveillance of gastrointestinal stromal tumours (GISTs). Risk stratification schemes, based on size, mitotic count, and anatomical site of origin of the GIST, help in planning preoperative and postoperative imaging strategies especially in determining the frequency and duration of surveillance; however, there is no clear consensus on the optimal imaging strategies in patients with GISTs who are completely cured by surgery and patients who are at risk of recurrence. In addition, current surveillance protocols depend on the resectability of the primary tumour and presence of metastatic disease. The objective of this article is to provide a comprehensive review of the role of the different imaging methods for surveillance of GISTs, focusing on the guidelines recommended by National Comprehensive Cancer Network and European Society of Medical Oncology - European Network for Rare adult solid Cancers, and to propose practical guidelines for surveillance of GISTs for various risk categories.

Imaging of hepatic toxicity of systemic therapy in a tertiary cancer centre: chemotherapy, haematopoietic stem cell transplantation, molecular targeted therapies, and immune checkpoint inhibitors.

The purpose of this review is to familiarise radiologists with the spectrum of hepatic toxicity seen in the oncology setting, in view of the different systemic therapies used in cancer patients. Drug-induced liver injury can manifest in various forms, and anti-neoplastic agents are associated with different types of hepatotoxicity. Although chemotherapy-induced liver injury can present as hepatitis, steatosis, sinusoidal obstruction syndrome, and chronic parenchymal damages, molecular targeted therapy-associated liver toxicity ranges from mild liver function test elevation to fulminant life-threatening acute liver failure. The recent arrival of immune checkpoint inhibitors in oncology has introduced a new range of immune-related adverse events, with differing mechanisms of liver toxicity and varied imaging presentation of liver injury. High-dose chemotherapy regimens for haematopoietic stem cell transplantation are associated with sinusoidal obstruction syndrome. Management of hepatic toxicity depends on the clinical scenario, the drug in use, and the severity of the findings. In this article, we will (1) present the most common types of oncological drugs associated with hepatic toxicity and associated liver injuries; (2) illustrate imaging findings of hepatic toxicities and the possible differential diagnosis; and (3) provide a guide for management of these conditions.

Borderline resectable pancreatic cancer: conceptual evolution and current approach to image-based classification.

BACKGROUND: Diagnostic imaging plays a critical role in the initial diagnosis and therapeutic monitoring of pancreatic adenocarcinoma. Over the past decade, the concept of 'borderline resectable' pancreatic cancer has emerged to describe a distinct subset of patients existing along the spectrum from resectable to locally advanced disease for whom a microscopically margin-positive (R1) resection is considered relatively more likely, primarily due to the relationship of the primary tumor with surrounding vasculature. MATERIALS AND METHODS: This review traces the conceptual evolution of borderline resectability from a radiological perspective, including the debates over the key imaging criteria that define the thresholds between resectable, borderline resectable, and locally advanced or metastatic disease. This review also addresses the data supporting neoadjuvant therapy in this population and discusses current imaging practices before and during treatment. RESULTS: A growing body of evidence suggests that the borderline resectable group of patients may particularly benefit from neoadjuvant therapy to increase the likelihood of an ultimately margin-negative (R0) resection. Unfortunately, anatomic and imaging criteria to define borderline resectability are not yet universally agreed upon, with several classification systems proposed in the literature and considerable variance in institution-by-institution practice. As a result of this lack of consensus, as well as overall small patient numbers and lack of established clinical trials dedicated to borderline resectable patients, accurate evidence-based diagnostic categorization and treatment selection for this subset of patients remains a significant challenge. CONCLUSIONS: Clinicians and radiologists alike should be cognizant of evolving imaging criteria for borderline resectability given their profound implications for treatment strategy, follow-up recommendations, and prognosis.

Assessment of metastatic risk of gastric GIST based on treatment-naïve CT features.

OBJECTIVE: To study whether the CT features of treatment-naïve gastric GIST may be used to assess metastatic risk. METHODS: In this IRB approved retrospective study, with informed consent waived, contrast enhanced CT images of 143 patients with pathologically confirmed treatment-naïve gastric GIST (74 men, 69 women; mean age 61 years, SD ± 14) were reviewed in consensus by two oncoradiologists blinded to clinicopathologic features and clinical outcome and morphologic features were recorded. The metastatic spread was recorded using available imaging studies and electronic medical records (median follow up 40 months, interquartile range, IQR, 21-61). The association of maximum size in any plane (≤10 cm or >10 cm), outline (smooth or irregular/lobulated), cystic areas (≤50% or >50%), exophytic component (≤50% or >50%), and enhancing solid component (present or absent) with metastatic disease were analyzed using univariate (Fisher's exact test) and multivariate (logistic regression) analysis. RESULTS: Metastatic disease developed in 42 (29%) patients (28 at presentation, 14 during follow-up); 23 (16%) patients died. On multivariate analysis, tumor size >10 cm (p = 0.0001, OR 9.9), irregular/lobulated outline (p = 0.001, OR 5.6) and presence of a enhancing solid component (p < 0.0001, OR 9.1) were independent predictors of metastatic disease. On subgroup analysis, an irregular/lobulated outline and an enhancing solid component were more frequently associated with metastases in tumors ≤5 cm and >5-≤10 cm (p < 0.05). CONCLUSION: CT morphologic features can be used to assess the metastatic risk of treatment-naïve gastric GIST. Risk assessment based on pretreatment CT is especially useful for patients receiving neoadjuvant tyrosine kinase inhibitors and those with tumors <5 cm in size.

Metastasis in dedifferentiated liposarcoma: Predictors and outcome in 148 patients.

OBJECTIVE: To describe the pattern of dedifferentiated liposarcoma (DDLPS) metastases and to analyze their predictors and outcome. MATERIALS AND METHODS: In this retrospective study, we reviewed the imaging and clinical records of all consenting patients with histopathology-confirmed DDLPS seen from 2000 through 2012. The predictive value of clinical and histopathologic parameters for metastasis later in the disease course was analyzed using univariate and multivariate analyses. Survival of patients with and without metastasis was compared using Log-rank test. RESULTS: Records of 148 patients (57 women, 91 men; mean age 59 years, range 30-87 years) were reviewed. Distant metastases were observed in 44/148 patients (29.7%), 9/44 (20.5%) at presentation and 35/44 (79.5%) developing them later at a median interval of 8 months (IQR = 0.80-26 months). Median duration of follow-up was 38 months (IQR = 18-74 months) with 77/148 patients (31 with metastases) deceased at the time of analysis. Median survival was 28 months (IQR = 10-56 months) for patients with metastases and 38 months (IQR, 17-65 months) for patients without metastases (p = 0.0123, Log-Rank test; Hazard ratio 1.79 [95% confidence interval 1.11-2.84]). Lung was the most common site of metastases (33 patients, 22.3%). On univariate analysis, grade and local recurrence were associated with subsequent risk of metastasis where as age, tumor size, site, de novo dedifferentiation, number of previous surgical resections, margin positivity and chemoradiation were not. On multivariate analysis, high tumor grade (p-value = 0.0005, OR 5.05; 95% CI 2.01-13.48) and local recurrence (p-value = 0.0025, OR 4.46; 95% CI 1.67-13.40) predicted metastasis. CONCLUSION: Lung was most frequent site of DDLPS metastases. Risk of developing metastatic disease was statistically associated with tumor grade and local recurrence. Metastatic disease was associated with decreased survival.

Metastatic patterns of breast cancer subtypes: what radiologists should know in the era of personalized cancer medicine.

There is accumulating evidence that molecular phenotyping of breast cancer determines the timing, pattern, and outcome of metastatic disease. The most clinically relevant subtypes are hormonal-positive [oestrogen and progesterone receptor (ER/PR) positive], HER2 expressing, and triple-negative breast cancers (TNBCs). ER/PR-positive breast cancers demonstrate the best prognosis; however, metastases, in particular osseous disease, may develop much later. HER2-expressing breast cancers, although aggressive, have improved outcomes due to the advent of HER2-targeted therapies, with increased risk of central nervous system (CNS) relapses later. Finally, TNBCs present in younger women, BRCA1 mutations carriers, and carry the worst overall prognosis, with high incidence of CNS metastases, especially during the first 5 years of diagnosis. It is important for radiologists to understand the nuances of these breast cancer subtypes to predict metastatic behaviours and guide possible imaging surveillance.

Imaging features of primary and metastatic extremity synovial sarcoma: a single institute experience of 78 patients.

OBJECTIVE: To study the appearance of primary and metastatic extremity synovial sarcoma (SS) on cross-sectional imaging. METHODS: In this institutional review board-approved, Health Insurance Portability and Accountability Act-compliant retrospective study, the imaging features of 78 patients (42 males and 36 females; mean age, 40 years) with primary and metastatic extremity SS on MRI and multidetector CT were reviewed, with baseline MRI of the primary available in 31 patients. RESULTS: Primary SSs were predominantly well-circumscribed (27/31) and heterogeneously enhancing solid (18/31) or solid-cystic (13/31) tumours. Imaging features visualized included the presence of perilesional oedema (14/31), interfascial (15/31) and intercompartmental extension (7/31), triple sign (11/31), intratumoral haemorrhage (10/31), calcification (6/31), bowl of grapes appearance (5/31) and bone involvement (3/31). Smaller T1 stage tumours (8/31) appeared as heterogeneously enhancing lesions, with some lesions demonstrating interfascial and intercompartmental extension and perilesional oedema. Recurrent/metastatic disease developed in 49/78 (63%) patients. Of these, 20/78 (26%) had metastasis at presentation, while the remaining developed metastatic disease at a median interval of 27 months (range, 3-161 months). Pleuropulmonary metastases (46/78) were the most common sites, with most of the metastases being pleural based. On univariate analysis, larger tumour size, the presence of perilesional oedema, intercompartmental extension, the presence of intralesional haemorrhage and bowl of grapes appearance on MRI were associated with a significantly higher incidence of metastatic disease. CONCLUSION: Certain imaging features of primary SS predict the risk of development of metastatic disease. Imaging features of T1 stage tumours included heterogeneous enhancement, interfascial extension and perilesional oedema. Pleural-based metastases are commonly seen in SSs. ADVANCES IN KNOWLEDGE: Imaging features of primary SS correlate with metastatic disease. Pleural-based metastases are often present in SSs.

Differences in CT features of peritoneal carcinomatosis, sarcomatosis, and lymphomatosis: retrospective analysis of 122 cases at a tertiary cancer institution.

AIMS: To study the differences in the imaging features of spread from the three cancer cell lines, namely epithelial, sarcomatoid, and lymphoid, resulting in peritoneal carcinomatosis, peritoneal sarcomatosis, and peritoneal lymphomatosis, respectively. MATERIALS AND METHODS: In this institutional review board-approved Health Insurance Portability and Accountability Act (HIPAA)-compliant retrospective study, an electronic radiology database was searched to identify patients with peritoneal tumour spread who underwent CT imaging at Dana-Farber Cancer Institute, a tertiary cancer institution, between January 2011 and December 2012. Out of 1214 patients with possible peritoneal tumour spread on the radiology reports, 122 patients were included with histopathologically confirmed peritoneal disease (50 randomly selected patients with peritoneal carcinomatosis and sarcomatosis each, and all 22 patients with lymphomatosis). Two blinded, fellowship-trained radiologists in consensus reviewed the CT images in random order and recorded the imaging findings of peritoneal tumour spread. The statistical analysis was performed in two steps: the first comparing incidence of various features in each group and the second step was a pairwise analysis between each cohort. RESULTS: Peritoneal carcinomatosis more frequently had ascites, peritoneal thickening, and omental cake (all p ≤ 0.001). Measurable nodules were less common in peritoneal carcinomatosis (p < 0.001), and when present, were ill-defined and had an irregular outline (p ≤ 0.002). Peritoneal sarcomatosis more often had discrete nodules that were well defined and had a smooth outline and less frequently had ascites, peritoneal thickening, omental caking, serosal implants, and lymphadenopathy (all p ≤ 0.005). Peritoneal lymphomatosis frequently involved the omentum and mesentery, and often had associated lymphadenopathy and splenomegaly (all p ≤ 0.002). CONCLUSION: Peritoneal carcinomatosis, sarcomatosis, and lymphomatosis have distinctive patterns on imaging, which can help the radiologists to differentiate between them.

MDCT features of succinate dehydrogenase (SDH)-deficient gastrointestinal stromal tumours.

OBJECTIVE: To describe the multidetector CT (MDCT) features and metastatic pattern of succinate dehydrogenase (SDH)-deficient gastrointestinal stromal tumours (GISTs). METHODS: In this institutional review board-approved, Health Insurance Portability and Accountability Act-compliant study, we retrospectively identified 34 patients (20 females; mean age, 34 years; range, 12-59 years) with histopathology-confirmed SDH-deficient GIST, who were seen at our institution from 1999 through 2012. MDCT of primary tumour in 8 patients and follow-up imaging in all 34 patients over median follow-up of 106 months [interquartile range (IQR), 52-175 months] were reviewed by two radiologists in consensus. Clinical information was extracted from electronic medical records. RESULTS: Primary tumour in all 34 patients was located in the stomach. Mean tumour size (n = 8) was 9.6 cm (range, 8-14 cm). Primary tumours were lobulated, variable in growth pattern, hypo- (1/8) to isodense (7/8) and similar in enhancement to the skeletal muscle. Two were multifocal, four of eight had necrosis and one of eight had haemorrhage. Tumour rupture with haemoperitoneum and tumour-bowel fistula was noted in one patient each. During follow-up, 12/34 patients developed tumour in surgical bed, and 28/34 patients developed metastases. Most common sites of metastases were the liver (24/34), peritoneum (20/34) and lymph nodes (18/34). Carney triad and Carney-Stratakis syndrome were noted in 5/34 and 1/34 patients, respectively. At the time of writing, six patients had deceased at a median interval of 109 months (IQR, 54-126 months). CONCLUSION: SDH-deficient GISTs occur in young patients, commonly arise in stomach, can be multifocal and may be associated with Carney triad or Carney-Stratakis syndrome. They frequently metastasize to lymph nodes in addition to the liver and peritoneum and are associated with indolent course despite metastatic spread. ADVANCES IN KNOWLEDGE: The presence of features unusual for conventional GIST on imaging should alert the radiologist for the possibility of SDH-deficient GIST, especially, because SDH-deficient GISTs are resistant to imatinib. Young age at diagnosis, prolonged survival, association with Carney triad and Carney-Stratakis syndrome and occurrence of concurrent renal cell carcinoma and thyroid malignancies necessitates long-term follow-up of patients with SDH-deficient GISTs.

Imaging features of primary and metastatic alveolar soft part sarcoma: single institute experience in 25 patients.

OBJECTIVE: To describe imaging features of primary and metastatic alveolar soft part sarcoma (ASPS). METHODS: In this institutional review board-approved and Health Insurance Portability and Accountability Act-compliant retrospective study, 25 patients (14 males; mean age, 25 years; range, 18-40 years) with pathologically proven ASPS seen at our institute between 1995 and 2013 were included. Imaging of primary tumours in 5 patients and follow-up imaging in 25 patients were reviewed by 2 radiologists in consensus. Clinical information was obtained from electronic medical records. RESULTS: The most common sites for the primary tumour were extremities (17/25, 68%) and torso (6/25, 24%). Primary tumours (n = 5) were well circumscribed, compared with skeletal muscle, were isodense on CT, hyperintense on T1 and T2 weighted images with intense post-contrast enhancement, prominent feeders on CT and flow voids on MRI. Metastases developed in 23/25 (92%) patients, 18 at presentation. The most common sites of metastases were the lungs (100%), lymph nodes (74%), bones (57%) and brain (43%). Visceral and nodal metastases were hypervascular. At the time of reporting the results, 15 patients have died, 6 are alive and 4 were lost to follow-up. Median survival was 74 months for those without brain metastases (n = 8) and 60 months for those with brain metastases (n = 7). Median survival was shorter for patients with metastases at presentation. CONCLUSION: ASPS most commonly involves the lower extremities of young adults, is hypervascular on imaging, often metastasizes at presentation, frequently to lung, nodes, bones and brain, and has an indolent course despite metastases. Brain metastases and high tumour burden (number of metastatic sites) at presentation decreased survival in our study. ADVANCES IN KNOWLEDGE: ASPS has an unusual pattern of metastases to the brain and nodes in addition to lung and bones. It has an indolent course despite metastases.

Radiologic assessment of earliest, best, and plateau response of gastrointestinal stromal tumors to neoadjuvant imatinib prior to successful surgical resection.

BACKGROUND: To determine the timing of earliest, best and plateau response to neoadjuvant imatinib in patients with GIST. MATERIALS AND METHODS: In this IRB-approved retrospective study, we included all 20 patients (10 women; mean age 61 years, range 30-83 years) with KIT-positive primary GIST who received neoadjuvant imatinib and underwent surgery between January 2001 and December 2012. Earliest (earliest time to partial response), best (percentage reduction in longest axial diameter [LAD] and volume correlated with RECIST 1.1 and volumetric criteria) and plateau (time point when there was <10% change in treatment response between two consecutive scans beyond best response) responses were analyzed on review of imaging. RESULTS: Median tumor size at baseline was 7.2 cm (range, 3.0-31.4 cm). Median duration of neoadjuvant imatinib was 32 weeks (IQR, 16-36 weeks). Partial response was noted in 16/20 patients (median interval = 16 weeks; IQR, 7-26 weeks); 4/20 had stable disease. Median time to earliest PR was 16 weeks (IQR, 7-26 weeks). At best response, median decrease in LAD and volume were 43% (IQR, 31-48%) and 83% (IQR, 63-87%), (median interval = 28 weeks; IQR, 18-37 weeks), at which point 10 tumors were resected. Plateau response (45% [IQR, 35-45%] LAD reduction) was noted in the remaining 10 patients (median interval = 34 weeks; IQR, 26-41 weeks) before resection. Tumor size, location or risk category did not correlate with best response or time to best response. CONCLUSION: Best response to neoadjuvant imatinib was seen at 28 weeks irrespective of tumor size and location. Plateau response was seen at 34 weeks, beyond which further treatment may not be beneficial.

Multidetector-row CT of tumour-bowel fistula: Experience at a tertiary cancer centre.

AIM: To study the clinical and multidetector computed tomography (MDCT) features of tumour-bowel fistula (TBF). MATERIALS AND METHODS: Fifty-one patients (27 women; mean age 57.4 years, range 30-77years) with TBF presenting to our institution between January 2005 and February 2012 were identified retrospectively from the radiology database. MDCT images before, at, and subsequent to diagnosis of TBF were reviewed by three radiologists in consensus; clinical presentation, management, and outcome were documented from electronic medical records. RESULTS: Of 51 patients, small bowel (n = 22) was the most common site with gastrointestinal stromal tumour (GIST) being the most common sarcoma subtype (n = 10). TBF was treatment-associated (TTBF) in 40 patients [78%; 22 of whom had received molecular targeted therapy (MTT)], and spontaneous (STBF) in 11 patients (22%). Thirty-one patients (61%) were symptomatic at the time of TBF detection. TTBF was more often asymptomatic (19/40 versus 1/11; Fisher's exact test p = 0.03). In the TTBF group, 16 had a partial response, seven had stable disease, and 17 had progressive disease. Treatment was discontinued or changed to an alternative regimen in 27/40 patients, and 13/40 patients continued with the same regimen. TBF persisted in 27/33 patients (82%) who underwent CT follow-up. Thirty-one of the 51 patients were deceased at the time of analysis. Time from diagnosis of TBF to death was shorter with STBF (1.8 months) than with TTBF (6.4 months). CONCLUSION: TBF is often associated with MTT and can be seen with treatment response or progression. TTBF is more frequently asymptomatic. TBF is usually managed conservatively by discontinuing treatment, but often persists on CT follow-up.

MDCT of primary, locally recurrent, and metastatic duodenal gastrointestinal stromal tumours (GISTs): a single institution study of 25 patients with review of literature.

AIM: To describe the multidetector computed tomography (MDCT) features of primary, locally recurrent, and metastatic duodenal gastrointestinal stromal tumours (GISTs). MATERIALS AND METHODS: In this institutional review board-approved, Health Insurance Portability and Accountability Act of 1996 (HIPAA)-compliant, retrospective study, 25 patients [13 men, 12 women; mean age 56 years (34-74 years)] with histopathologically confirmed duodenal GISTs seen at Dana Farber Cancer Institute and Brigham and Women's Hospital from December 1999 to October 2009 were identified. The MDCT of primary tumours in six patients and follow-up imaging in all the 25 patients was reviewed by two radiologists in consensus. Electronic medical records were reviewed to document the clinical characteristics and management. RESULTS: The mean size of the primary tumour was 3.7 cm (range 2.5-5.6 cm). Three of six primary tumours were in the second and third portions of the duodenum, one in the third portion, one in the third and fourth portions, and one in the fourth portion. Three of six of the tumours were exophytic, two were both exophytic and intraluminal, and one was intramural. The tumours were well-circumscribed, round or oval masses, with few lobulations, and were either homogeneously hyper-enhancing or heterogeneously isodense at MDCT. None of the tumours had necrosis, haemorrhage, calcification, or loco regional lymphadenopathy on imaging. Sixteen of 25 (64%) patients developed metastatic disease, the most common sites being liver (14/16; 87.5%) and peritoneum (5/16; 31%). CONCLUSION: Duodenal GISTs are well-circumscribed, round or oval masses, and occur in the second through fourth portions of the duodenum, without lymphadenopathy or duodenal obstruction. Duodenal GISTS metastasize frequently to the liver and peritoneum.

Resistance to treatment in gastrointestinal stromal tumours: what radiologists should know.

Gastrointestinal stromal tumour resistance to treatment with imatinib occurs due to pre-existing or acquired mutations. Computed tomography and positron-emission tomography play an essential role in prompt recognition of resistance to treatment. Primary resistance to treatment, which is encountered in the first 6 months of treatment, is associated with specific mutations. Imaging of these tumours shows no anatomical or metabolic response to treatment. Secondary resistance to treatment, which develops after an initial response, is associated with a variety of mutations acquired after the start of treatment. Imaging findings of secondary resistance are of disease progression.

Imaging features of primary anorectal gastrointestinal stromal tumors with clinical and pathologic correlation.

PURPOSE: To evaluate the imaging features of anorectal gastrointestinal stromal tumors (GISTs) with clinical and histopathologic correlation. MATERIALS AND METHODS: In this Institutional Review Board-approved, Health Insurance Portability and Accountability Act-compliant retrospective study, 16 patients (12 men; mean age 66 years (30-89 years)) with pathologically proven anorectal GISTs seen at our institution from January 2001 to July 2011 were identified. Electronic medical records were reviewed to obtain clinical data. Pretreatment imaging studies (computed tomography (CT) in 16 patients, magnetic resonance imaging (MRI) in 9 patients and fluorodeoxyglucose (FDG)-positron emission tomography (PET)/CT in 8 patients) were evaluated by 2 radiologists until consensus. The location, size and imaging features of the primary tumor and metastases at presentation, if any, were recorded, and correlated with clinical data and pathologic features (histologic type, presence of necrosis, mitotic activity, risk category, immunohistochemical profile). RESULTS: The mean tumor size was 6.9 × 6.0 cm. Of the 16 tumors, 11 (68.7%) were infralevator, 4 (25%) supra and infralevator and 1 (6.3%) supralevator; 9 (56.2%) were exophytic, 6 (37.5%) both exophytic and intraluminal, and 1 (6.3%) was intraluminal. The tumors were iso- to minimally hypoattenuating to muscle on CT, iso- to minimally hypointense on T1-weighted images, hyperintense on T2-weighted images and showed variable enhancement. Necrosis was seen in 4 (25%), and hemorrhage and calcification in 2 (12.5%) patients each. The tumors were FDG avid with a mean maximum standardized uptake value of 11 (8.4-16.8). All tumors were positive for KIT and CD34. Distant metastasis to liver was seen in 1 patient (6.3%) at presentation. CONCLUSION: Anorectal GISTs are well-circumscribed, non-circumferential, predominantly infralevator, intramural or exophytic, FDG-avid, hypoattenuating masses, and present without lymphadenopathy or intestinal obstruction.

Malignant peripheral nerve sheath tumors: prognostic impact of rhabdomyoblastic differentiation (malignant triton tumors), neurofibromatosis 1 status and location.

PURPOSE: The purpose of this study was to assess the impact of rhabdomyoblastic differentiation [malignant triton tumors (MTT)], neurofibromatosis 1 (NF1) status and location on the outcome of malignant peripheral nerve sheath tumors. METHODS: In this IRB-approved, HIPAA-compliant retrospective study medical records of 84 patients with pathologically confirmed MPNST from 1999 to 2011 were retrospectively reviewed. Patient and tumor characteristics including size, location, NF1 status, absence or presence of rhabdomyoblastic differentiation (MPNST versus MTT, respectively), recurrence and metastatic patterns and outcomes were evaluated. RESULTS: Of 84 patients, 62 were MPNST and 22 were MTT. MTT occurred in older patients than MPNST (50 years versus 40.7 years, p = 0.04) and were larger (12.3 cm versus 8.1 cm, p = 0.01). While there was no difference between the location, rate of recurrent or metastasis disease, and metastatic pattern between MTT and MPNST groups, MTT had shorter metastasis-free interval (median, 1 month versus 9 months, p = 0.02) and shorter survival (median, 10 months versus 43 months, p < 0.0001). NF1 status, while associated with earlier diagnosis (mean age, 35.1 years versus 46.5 years, p = 0.008), had no impact on rate of MTT or on prognosis. Patients with primary in the torso had shorter survival than those with extremity primary (median, 15 months versus 47 months, p = 0.0004). Multivariate analysis using the Cox proportional hazard regression model yielded age (p = 0.029), size (p = 0.0001), presence of rhabdomyoblastic differentiation (MTT) (p = 0.001), and location in the torso (p = 0.01) as independent predictors of survival. CONCLUSIONS: Among patients with malignant peripheral nerve sheath tumors, rhabdomyoblastic differentiation (MTT) and location in the torso are associated with poor prognosis. NF1 status has no impact on the prognosis.

Imaging features of bowel toxicities in the setting of molecular targeted therapies in cancer patients.

Molecular targeted therapies are becoming ubiquitous in cancer treatment. These drugs may cause gastrointestinal toxicities including perforation, pneumatosis, enteritis, colitis and fistula formation. Knowledge of these complications and their management enables early radiological identification and appropriate intervention, reducing patient morbidity and mortality.

Esophageal gastrointestinal stromal tumor: report of 7 patients.

PURPOSE: To evaluate imaging features of esophageal gastrointestinal stromal tumors (GIST) with clinical and histopathologic correlation and imaging follow-up. MATERIALS AND METHODS: In this institutional review board-approved, Health Insurance Portability and Accountability Act-compliant retrospective study, 14 patients with pathologically proven esophageal GIST seen from January 2001 to October 2011, 7 patients (4 women; mean age 70 years, range 56-87 years) who had imaging of primary tumor and follow-up imaging at our institution were included. Imaging studies were evaluated by 3 radiologists in consensus. Location, size and imaging features of primary tumor and metastases, if any, were recorded, and correlated with pathologic (histopathologic subtype, presence of necrosis, mitotic rate, immunohistochemical profile) and clinical (treatment-related changes, distant spread and outcome) parameters. RESULTS: Of 7 tumors, 5 were located in the lower esophagus and 2 in mid-esophagus. Four were intraluminal, 2 were exophytic, and 1 was intramural. All 7 patients underwent computed tomography (CT); tumors appeared as well-circumscribed, hypoattenuating masses showing mild enhancement, with mean size of 5.7 × 4.2 cm. Necrosis and calcification were seen in 1 tumor each. Five patients underwent fluorodeoxyglucose (FDG)-positron emission tomography (PET)/CT. GISTs were FDG avid with mean standardized uptake value (SUV)[max] of 9.5 (4.5-12.3). All tumors were positive for KIT (7/7) and CD34 (6/6). Distant metastases to liver and pleura were seen in 1 patient. On imatinib treatment, the tumors responded with decreased attenuation values and unchanged size on CT, and decreased SUV[max] of primary tumor and metastases on FDG-PET/CT. CONCLUSION: Esophageal GISTs are well-circumscribed, FDG-avid, hypoattenuating masses that can metastasize to liver and pleura, and respond to imatinib treatment with decreased attenuation value on CT and decreased SUV[max] on FDG-PET/CT.

Imaging features of primary and secondary malignant tumours of the sacrum.

Malignant tumours of the sacrum may be primary or secondary. While sacral metastases are frequently encountered, a diagnostic dilemma can present when there is a single sacral bone tumour with no history or evidence of malignancy elsewhere in the body. Familiarity with the imaging features and clinical presentations of primary malignant bone tumours is helpful in narrowing the differential. This pictorial review will illustrate with both common and uncommon malignant sacral tumours CT, MRI and positron emission tomography/CT, highlighting the specific features of each.