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

Koch MR, Jagannathan JP, Shinagare AB, Krajewski KM, Raut CP, Hornick JL, Ramaiya NH - Cancer Imaging (2013)

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, USA.

ABSTRACT

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.

Show MeSH

Related in: MedlinePlus

A 30-year-old man with an anorectal GIST. Coronal T12-weighted MR image shows a small well-defined T2 hyperintense infralevator intersphincteric mass (arrow).
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3569670&req=5

Figure 1: A 30-year-old man with an anorectal GIST. Coronal T12-weighted MR image shows a small well-defined T2 hyperintense infralevator intersphincteric mass (arrow).

Mentions: Important morphologic features of the tumors included in this study are summarized in Table 1. Eleven of 16 (68.7%) tumors were infralevator (Fig. 1), 4/16 (25%) were both supra- and infralevator (Fig. 2), and 1/16 (6.3%) tumor was completely supralevator. Two of the infralevator tumors were very low lying, close to the anal verge. The mean distance of the infralevator tumors from the anal verge was 2.9 cm (range 0.8–4 cm). All the tumors were well circumscribed, and 7 tumors were round with smooth margins, 6 were lobulated, 2 were dumbbell shaped and 1 was ovoid. None of the tumors had irregular or infiltrative margins. The mean tumor size was 6.9 × 6.0 cm, ranging in size from 1.7 to 11.3 cm in the long dimension and 0.6 to 10 cm in the short dimension. Seven out of 8 incidentally detected tumors in our series were more than 5 cm in size (range 5.8–11.3 cm). There was good correlation between tumor size measured on CT and MRI. A purely exophytic growth pattern was seen in 9/16 (56.2%); both exophytic and intraluminal components were present in 6/16 (37.5%), and in 1/16 (6.3%) tumors were predominantly intraluminal. Table 1 gives the location of tumors with respect to the levator ani muscle on coronal images, and the location along the rectal circumference in the transverse plane. Ten of 16 (62.5%) tumors were located anteriorly or anterolaterally, and contacted the prostate causing a mass effect. Invasion into the prostate was suspected on CT in 2 (12.5%) patients, however at surgery, the masses were free from the prostate. In 2 other patients where the CT suggested invasion/mass arising from the prostate, MRI performed subsequently showed a clear fat plane between the mass and the prostate.Figure 1


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

Koch MR, Jagannathan JP, Shinagare AB, Krajewski KM, Raut CP, Hornick JL, Ramaiya NH - Cancer Imaging (2013)

A 30-year-old man with an anorectal GIST. Coronal T12-weighted MR image shows a small well-defined T2 hyperintense infralevator intersphincteric mass (arrow).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3569670&req=5

Figure 1: A 30-year-old man with an anorectal GIST. Coronal T12-weighted MR image shows a small well-defined T2 hyperintense infralevator intersphincteric mass (arrow).
Mentions: Important morphologic features of the tumors included in this study are summarized in Table 1. Eleven of 16 (68.7%) tumors were infralevator (Fig. 1), 4/16 (25%) were both supra- and infralevator (Fig. 2), and 1/16 (6.3%) tumor was completely supralevator. Two of the infralevator tumors were very low lying, close to the anal verge. The mean distance of the infralevator tumors from the anal verge was 2.9 cm (range 0.8–4 cm). All the tumors were well circumscribed, and 7 tumors were round with smooth margins, 6 were lobulated, 2 were dumbbell shaped and 1 was ovoid. None of the tumors had irregular or infiltrative margins. The mean tumor size was 6.9 × 6.0 cm, ranging in size from 1.7 to 11.3 cm in the long dimension and 0.6 to 10 cm in the short dimension. Seven out of 8 incidentally detected tumors in our series were more than 5 cm in size (range 5.8–11.3 cm). There was good correlation between tumor size measured on CT and MRI. A purely exophytic growth pattern was seen in 9/16 (56.2%); both exophytic and intraluminal components were present in 6/16 (37.5%), and in 1/16 (6.3%) tumors were predominantly intraluminal. Table 1 gives the location of tumors with respect to the levator ani muscle on coronal images, and the location along the rectal circumference in the transverse plane. Ten of 16 (62.5%) tumors were located anteriorly or anterolaterally, and contacted the prostate causing a mass effect. Invasion into the prostate was suspected on CT in 2 (12.5%) patients, however at surgery, the masses were free from the prostate. In 2 other patients where the CT suggested invasion/mass arising from the prostate, MRI performed subsequently showed a clear fat plane between the mass and the prostate.Figure 1

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, USA.

ABSTRACT

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.

Show MeSH
Related in: MedlinePlus