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) Low-power image stained with hematoxylin and eosin of a rectal GIST showing the tumor located in the muscularis propria. (b) High-power image stained with hematoxylin and eosin shows that the tumor is composed of fascicles of uniform spindle cells with elongated nuclei and palely eosinophilic cytoplasm. (c) Immunohistochemistry image showing diffuse positivity for KIT. The tumor also showed diffuse positivity for CD34 (not shown).
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3569670&req=5

Figure 5: (a) Low-power image stained with hematoxylin and eosin of a rectal GIST showing the tumor located in the muscularis propria. (b) High-power image stained with hematoxylin and eosin shows that the tumor is composed of fascicles of uniform spindle cells with elongated nuclei and palely eosinophilic cytoplasm. (c) Immunohistochemistry image showing diffuse positivity for KIT. The tumor also showed diffuse positivity for CD34 (not shown).

Mentions: Histologically, 15/16 (93.7%) tumors were of spindle cell type (Fig. 5) and 1/16 (6.3%) was of mixed histology, predominantly epithelioid type. Immunohistochemical (IHC) studies were performed in all cases; 16/16 (100%) tumors were positive for KIT (Fig. 5). All tumors (n = 10) tested for CD34 were also positive (100%). IHC for desmin (n = 10) was negative in all cases (100%). In 9 cases, IHC was performed for S-100 and was negative in 7 cases (78%) and positive in 2 cases (22%). SMA was negative in 7 of 9 tumors tested (78%) and positive in 2 (22%). Mitotic rate ranged from 1 to 21 per 50 HPF. Based on tumor size (documented on initial imaging) and mitotic rates, 1/16 (6.3%) tumor was classified as having no risk for malignant behavior, 1 (6.3%) was considered low risk, 1 (6.3%) with moderate risk, and 12/16 (75%) were considered high risk (Table 1). Risk stratification could not be performed on 1 (6.3%) tumor, as the mitotic rate could not be accurately assessed on the small pretreatment biopsy. Necrosis was present on the biopsy specimens in 4/16 (25%) tumors, all of which belonged to the high-risk category. Two tumors were analyzed for the presence of KIT gene mutations; a typical KIT exon 11 mutation was detected in both cases.Figure 5


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) Low-power image stained with hematoxylin and eosin of a rectal GIST showing the tumor located in the muscularis propria. (b) High-power image stained with hematoxylin and eosin shows that the tumor is composed of fascicles of uniform spindle cells with elongated nuclei and palely eosinophilic cytoplasm. (c) Immunohistochemistry image showing diffuse positivity for KIT. The tumor also showed diffuse positivity for CD34 (not shown).
© Copyright Policy
Related In: Results  -  Collection

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

Figure 5: (a) Low-power image stained with hematoxylin and eosin of a rectal GIST showing the tumor located in the muscularis propria. (b) High-power image stained with hematoxylin and eosin shows that the tumor is composed of fascicles of uniform spindle cells with elongated nuclei and palely eosinophilic cytoplasm. (c) Immunohistochemistry image showing diffuse positivity for KIT. The tumor also showed diffuse positivity for CD34 (not shown).
Mentions: Histologically, 15/16 (93.7%) tumors were of spindle cell type (Fig. 5) and 1/16 (6.3%) was of mixed histology, predominantly epithelioid type. Immunohistochemical (IHC) studies were performed in all cases; 16/16 (100%) tumors were positive for KIT (Fig. 5). All tumors (n = 10) tested for CD34 were also positive (100%). IHC for desmin (n = 10) was negative in all cases (100%). In 9 cases, IHC was performed for S-100 and was negative in 7 cases (78%) and positive in 2 cases (22%). SMA was negative in 7 of 9 tumors tested (78%) and positive in 2 (22%). Mitotic rate ranged from 1 to 21 per 50 HPF. Based on tumor size (documented on initial imaging) and mitotic rates, 1/16 (6.3%) tumor was classified as having no risk for malignant behavior, 1 (6.3%) was considered low risk, 1 (6.3%) with moderate risk, and 12/16 (75%) were considered high risk (Table 1). Risk stratification could not be performed on 1 (6.3%) tumor, as the mitotic rate could not be accurately assessed on the small pretreatment biopsy. Necrosis was present on the biopsy specimens in 4/16 (25%) tumors, all of which belonged to the high-risk category. Two tumors were analyzed for the presence of KIT gene mutations; a typical KIT exon 11 mutation was detected in both cases.Figure 5

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