Fluid retention associated with imatinib treatment in patients with gastrointestinal stromal tumor: quantitative radiologic assessment and implications for management

Objective

We aimed to describe radiologic signs and time-course of imatinib-associated fluid retention (FR) in patients with gastrointestinal stromal tumor (GIST), and its implications for management.

Materials and Methods

In this Institutional Review Board-approved, retrospective study of 403 patients with GIST treated with imatinib, 15 patients with imaging findings of FR were identified by screening radiology reports, followed by manual confirmation. Subcutaneous edema, ascites, pleural effusion, and pericardial effusion were graded on a four-point scale on CT scans; total score was the sum of these four scores.

Results

The most common radiologic sign of FR was subcutaneous edema (15/15, 100%), followed by ascites (12/15, 80%), pleural effusion (11/15, 73%), and pericardial effusion (6/15, 40%) at the time of maximum FR. Two distinct types of FR were observed: 1) acute/progressive FR, characterized by acute aggravation of FR and rapid improvement after management, 2) intermittent/steady FR, characterized by occasional or persistent mild FR. Acute/progressive FR always occurred early after drug initiation/dose escalation (median 1.9 month, range 0.3-4.0 months), while intermittent/steady FR occurred at any time. Compared to intermittent/steady FR, acute/progressive FR was severe (median score, 5 vs. 2.5, p = 0.002), and often required drug-cessation/dose-reduction.

Conclusion

Two distinct types (acute/progressive and intermittent/steady FR) of imatinib-associated FR are observed and each type requires different management.

MRI findings of radiation-associated angiosarcoma of the breast (RAS)

PURPOSE

To describe the magnetic resonance imaging (MRI) characteristics of radiation-associated breast angiosarcomas (RAS).

MATERIALS AND METHODS

In this Institutional Review board (IRB)-approved retrospective study, 57 women were diagnosed with pathologically confirmed RAS during the study period (January 1999 to May 2013). Seventeen women underwent pretreatment breast MRI (prior to surgical resection or chemotherapy), of which 16 studies were available for review. Imaging features, including all available mammograms, ultrasounds, and breast MRIs, of these patients were evaluated by two radiologists independently and correlated with clinical management and outcomes.

RESULTS

The median age of patients at original breast cancer diagnosis was 69.3 years (range 42-84 years), with average time from initial radiation therapy to diagnosis of RAS of 7.3 years (range 5.1-9.5 years). Nine women had mammograms (9/16, 56%) and six had breast ultrasound (US) (6/16, 38%) prior to MRI, which demonstrated nonsuspicious findings in 5/9 mammograms and 3/6 ultrasounds. Four patients had distinct intraparenchymal masses on mammogram and MRI. MRI findings included diffuse T2 high signal skin thickening (16/16, 100%). Nearly half (7/16, 44%) of patients had T2 low signal intensity lesions; all lesions rapidly enhanced on postcontrast T1 -weighted imaging. All women underwent surgical resection, with 8/16 (50%) receiving neoadjuvant chemotherapy. Four women died during the study period.

CONCLUSION

Clinical, mammographic, and sonographic findings of RAS are nonspecific and may be occult on conventional breast imaging; MRI findings of RAS include rapidly enhancing dermal and intraparenchymal lesions, some of which are low signal on T2 weighted imaging.

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.

Update on the role of imaging in management of metastatic colorectal cancer

Evolution in the treatment of metastatic colorectal cancer (mCRC) has led to significant improvement in the survival of these patients. Surgery is useful in patients with resectable disease. Liver-directed therapies such as hepatic arterial infusion, transarterial radio- and chemoembolization, and percutaneous ablation are sometimes used by oncologists when the liver is the only site of metastatic disease. Unresectable mCRC is typically treated with systemic chemotherapy. First-line systemic chemotherapeutic regimens for mCRC are FOLFOX (combination of 5-fluorouracil/leucovorin [5-FU/LV] and oxaliplatin) and FOLFIRI (combination of 5-FU/LV and irinotecan) combined with molecular targeted drugs. Molecular targeted therapies that are effective in treating mCRC include antiangiogenic agents such as bevacizumab-an antibody against vascular endothelial growth factor-and antibodies directed against epidermal growth factor receptor (EGFR). EGFR-directed antibodies such as cetuximab and panitumumab have been shown to produce activity only in wild-type KRAS tumors. Imaging modalities such as multidetector computed tomography (CT), magnetic resonance imaging, and positron emission tomography/CT play a major role in the selection of appropriate treatment strategies. Assessment of treatment response in patients who undergo liver-directed and systemic therapy requires imaging at regular intervals. Recent studies have shown that alternative treatment response criteria may be more predictive of pathologic response in mCRC than conventional criteria such as Response Evaluation Criteria in Solid Tumors. Awareness of unusual response patterns, as well as of complications and toxicities, is helpful in guiding patient management.

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.

Comparison of performance of various tumour response criteria in assessment of regorafenib activity in advanced gastrointestinal stromal tumours after failure of imatinib and sunitinib

PURPOSE

To compare performance of various tumour response criteria (TRCs) in assessment of regorafenib activity in patients with advanced gastrointestinal stromal tumour (GIST) with prior failure of imatinib and sunitinib.

METHODS

Twenty participants in a phase II trial received oral regorafenib (median duration 47 weeks; interquartile range (IQR) 24-88) with computed tomography (CT) imaging at baseline and every two months thereafter. Tumour response was prospectively determined on using Response Evaluation Criteria in Solid Tumours (RECIST) 1.1, and retrospectively reassessed for comparison per RECIST 1.0, World Health Organization (WHO) and Choi criteria, using the same target lesions. Clinical benefit rate [CBR; complete or partial response (CR or PR) or stable disease (SD)≥16 weeks] and progression-free survival (PFS) were compared between various TRCs using kappa statistics. Performance of TRCs in predicting overall survival (OS) was compared by comparing OS in groups with progression-free intervals less than or greater than 20 weeks by each TRC using c-statistics.

RESULTS

PR was more frequent by Choi (90%) than RECIST 1.1, RECIST 1.0 and WHO (20% each), however, CBR was similar between various TRCs (overall CBR 85-90%, 95-100% agreement between all TRC pairs). PFS per RECIST 1.0 was similar to RECIST 1.1 (median 44 weeks versus 58 weeks), and shorter for WHO (median 34 weeks) and Choi (median 24 weeks). With RECIST 1.1, RECIST 1.0 and WHO, there was moderate concordance between PFS and OS (c-statistics 0.596-0.679). Choi criteria had less favourable concordance (c-statistic 0.506).

CONCLUSIONS

RECIST 1.1 and WHO performed somewhat better than Choi criteria as TRC for response evaluation in patients with advanced GIST after prior failure on imatinib and sunitinib.

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.

Acute pancreatitis associated with molecular targeted therapies: a retrospective review of the clinico-radiological features, management and outcome

PURPOSE

To study the presentation, radiological features, management and outcome of acute pancreatitis detected on imaging in patients receiving molecular targeted therapy (MTT).

MATERIALS AND METHODS

In this IRB-approved, HIPAA-compliant retrospective study, search of the radiology database from January 2005 through September 2012 revealed 91 cancer patients with radiologic evidence of acute pancreatitis. Of these, 15 patients receiving MTT (7 women, 8 men; mean age 59 years, range 25-84 years) and fulfilling the criteria of acute pancreatitis without any confounding factors were included. Imaging at initial diagnosis of pancreatitis and subsequently were reviewed by three radiologists in consensus; clinical presentation, management, and outcome were documented from the medical record.

RESULTS

Eleven patients had focal and four had diffuse pancreatitis. The tail of the pancreas (n = 6) was the most common site of focal pancreatitis. Of the 14/15 patients who underwent CT, modified CT severity index was 2 in 12 patients and 4 in 2 patients. One patient (1/15) who underwent only FDG-PET/CT showed focal pancreatitis. None of the patients had pancreatic necrosis or peripancreatic collections. Findings resolved in all the patients after discontinuation of MTT, except in one patient who died of progressive disease. No radiological or surgical interventions were required in any of the patients. Findings recurred in 4/9 patients (44%) in whom MTT was restarted.

CONCLUSION

MTT-associated pancreatitis is usually mild, focal, and managed conservatively with discontinuation of MTT. The imaging findings are subtle and in our study, pancreatitis recurred in 44% of patients after restarting MTT.

Molecular targeted therapies in non-GIST soft tissue sarcomas: what the radiologist needs to know

Non-gastrointestinal stromal soft tissue sarcomas are uncommon neoplasms that have a dismal prognosis due to a high incidence of metastases and a poor response to conventional chemotherapy. The identification of characteristic genetic alterations in several of these tumors has opened the window for molecular targeted therapies in patients who have failed conventional chemotherapy. Imaging plays a critical role in assessing the response to these novel therapeutic agents. Just like the response of gastrointestinal stromal tumors to imatinib, the response of non-gastrointestinal stromal soft tissue sarcomas to molecular targeted drugs is better evaluated on imaging by alternate tumor response criteria such as the Choi criteria. In addition, these drugs are associated with distinct class-specific drug toxicities that can come to attention for the first time on imaging. The purpose of this article is to provide a primer for the radiologist on the various molecular targeted therapies in advanced/metastatic non-gastrointestinal stromal soft tissue sarcomas with emphasis on the role of imaging in assessing treatment response and complications.

Peritoneal lymphomatosis: CT and PET/CT findings and how to differentiate between carcinomatosis and sarcomatosis

Peritoneal lymphomatosis is a rare manifestation of lymphoma, seen most frequently with non-Hodgkin lymphoma, and it is important to be familiar with this condition, because early diagnosis directly affects the management of patients. This review illustrates the spectrum of imaging findings in peritoneal lymphomatosis, highlighting the use of positron emission tomography/computed tomography, showing common and uncommon subtypes of lymphoma associated with this entity, and how to differentiate it from peritoneal carcinomatosis and peritoneal sarcomatosis.

Ipilimumab associated hepatitis: imaging and clinicopathologic findings

Ipilimumab is a novel immunomodulator demonstrating promising efficacy in treatment of melanoma and other cancers. The clinical benefit from ipilimumab can be hampered by the immure-related adverse events (irAEs) caused by dysregulation of host immune system. Ipilimumab associated hepatitis is also an important irAE, however, there have been limited descriptions of its clinicopathologic and imaging characteristics. We aim to describe the clinicopathologic and imaging characteristics of 6 patients who were diagnosed as ipilimumab associated hepatitis during the ipilimumab treatment for melanoma. The clinical features of these patients were as follows: (1) severe cases with systemic symptoms and highly increased level of liver function tests (LFTs), and (2) mild asymptomatic cases with mildly increased level of LFTs. In severe cases with ALT >1,000 IU/L, imaging findings were characterized by mild hepatomegaly, periportal edema, and periportal lymphadenopathy, while mild cases showed normal imaging findings. This spectrum of imaging findings in our series was similar to that of common causes of acute hepatitis. Among 3 cases with pathologic specimen, two cases showed severe panlobular hepatitis with prominent perivenular infiltrate with endothelialitis, suggestive of predominant injury to hepatocytes, while the other case showed mild portal mononuclear infiltrate around proliferated bile ductules, suggestive of predominant injury to bile ducts. In summary, ipilimumab associated hepatitis may demonstrate variable imaging findings according to its clinical severity, and histologically may manifest either as a predominant injury to hepatocytes (acute hepatitis pattern) or as a predominant injury to bile ducts (biliary pattern).

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.

Case report: Calcifying fibrous tumor presenting as an asymptomatic pelvic mass

Calcifying fibrous tumor (CFT) is a rare benign mesenchymal tumor most commonly found in the soft tissues of the extremities and pleura. It is characterized by hyalinized collagenous fibrous tissue, with bland spindle cells, psammomatous or dystrophic calcifications, and focal lymphoplasmacytic infiltrate. CFT of the gastrointestinal tract is exceedingly uncommon. We report a case of CFT arising from the small intestine and associated mesentery; this case was identified incidentally in an otherwise healthy 45-year-old man.

Imaging features of primary extranodal histiocytic sarcoma: report of two cases and a review of the literature

Histiocytic sarcoma is an extremely rare and aggressive malignancy of bone marrow origin that occurs in lymph nodes, skin, and the gastrointestinal tract. We report on the imaging features of two cases of primary histiocytic sarcoma, one in the retroperitoneum causing a tumor-bowel fistula and another with primary bone involvement.

Case report: atypical lipomatous tumor with unusual extensive metaplastic ossification

The presence of metaplastic ossification within atypical lipomatous tumor/well-differentiated liposarcoma (ALT/WDLPS) is a rare occurrence. When present, bone formation is most often found in association with a dedifferentiated component arising within the primary tumor. It is important for the radiologist not only to recognize the differential diagnosis of a calcified or ossified soft tissue mass but also be aware of the various soft tissue neoplasms, both aggressive and non-aggressive, that may show such features. We report a case of ALT/WDLPS with unusual extensive metaplastic bone formation without an element of dedifferentiated liposarcoma.

Pheochromocytoma and paraganglioma: imaging characteristics

The accurate diagnosis of adult pheochromocytoma and paraganglioma necessitates a multidisciplinary approach that includes clinical history, biochemical testing, and multimodality imaging such as computed tomography, magnetic resonance imaging, and nuclear medicine studies. This review illustrates the different imaging characteristics of primary adult pheochromocytomas as well as both sympathetic and parasympathetic paragangliomas. The review also describes known genetic associations and shows common metastatic patterns. Knowledge of the diverse appearance of pheochromocytomas and paragangliomas can result in early initial diagnosis or detection of disease recurrence thereby affecting patient management and prognosis.

Esophageal gastrointestinal stromal tumor: report of 7 patients

Abstract 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.