Wenrong Zhu

The multislice CT findings of renal carcinoma associated with XP11.2 translocation/TFE gene fusion and collecting duct carcinoma.

Background Renal cell carcinoma associated with Xp11.2 translocation and TFE gene fusion (Xp11.2/TFE RCC), and collecting duct carcinoma (CDC) are uncommon subtypes of renal cell carcinomas. Purpose To investigate the multislice CT (MSCT) characteristics of these two tumor types. Material and Methods: Nine patients with Xp11.2/TFE RCC and 10 patients with CDC were studied retrospectively. MSCT was undertaken to investigate differences in tumor characteristics and enhancement patterns. Results All patients had single tumors centered in the renal medulla. Two patients with each tumor type had lymph node involvement and there was a single case of hepatic metastasis (Xp11.2/TFE RCC). The mean tumor diameter of Xp11.2/TFE RCC tumors was significantly larger than for CDC tumors. Two patients with Xp11.2/TFE RCC had cystic components as did eight patients with CDC (P < 0.05). Calcifications were present in six patients, each with CDC. Clear tumor boundaries were visible in two patients with CDC and in nine with Xp11.2/TFE RCC (P< 0.05). The density of Xp11.2/TFE RCC tumors was greater than that of CDC tumors, normal renal cortex, or medulla on unenhanced CT. Enhancement was higher with Xp11.2/TFE RCC than with CDC tumors during all phases. Xp11.2/TFE RCC enhancement was higher than in the renal medulla during cortical and medullary phase but lower than in normal renal medulla during the delayed phase. CDC tumor enhancement was lower than that for normal renal medulla during all enhanced phases. Conclusion Both tumor types originated from the renal medulla. Distinguishing features included density on unenhanced CT, enhancement patterns, and capsule signs. Identifying these differences may aid diagnosis.

Comparative study of CT appearances in renal oncocytoma and chromophobe renal cell carcinoma

Background Renal oncocytoma (RO) and chromophobe renal cell carcinoma (ChRCC) share histologic and some imaging features. Purpose To investigate the multidetector computed tomography (MDCT) characteristics of these two tumor types. Material and Methods Fifty-six patients with RO and 54 patients with ChRCC were studied retrospectively. MDCT was undertaken to investigate differences in tumor characteristics. Results Calcifications were visible in 24 (42.8%) patients with RO and in 11 (20.4%) patients with ChRCC (P = 0.011). 26 patients with RO had stellate scars as did 14 patients with ChRCC (P = 0.025). Spoken-wheel-like enhancement was visible in 41 patients with RO and in 11 with ChRCC (P < 0.001). Thirty-nine (69.6%) patients with RO and nine (16.7%) patients with ChRCC showed segmental inversion (P < 0.001). Two patients with RO had retroperitoneal lymph node enlargement as did 13 patients with ChRCC (P = 0.002). Combined evaluation of stellate scar, spoken-wheel-like enhancement, and segmental enhancement inversion features were found to have a sensitivity of 99.1% (106 of 107), a specificity of 100% (3 of 3), a positive predictive value of 100% (106 of 106), and a negative predictive value of 75% (3 of 4). The attenuation of RO tumors was greater than that of ChRCC tumors, normal renal parenchyma on unenhanced CT (P = 0.031). Enhancement was higher with RO than with ChRCC tumors in all phases (P = 0.021, < 0.001, and 0.007, respectively). Conclusion CT imaging features such as stellate scar, spoken-wheel-like enhancement, and segmental enhancement inversion were more common in RO and they may help in differentiating RO from ChRCC.

The clinical and CT imaging features of metanephric adenoma.

Background Patients with metanephric adenoma have a good prognosis after undergoing total nephrectomy or local resection with kidney preservation. Accurate diagnosing is important for guiding clinical treatment. Only few previous case reports have been found focusing on the imaging findings of metanephric adenoma. Purpose To evaluate the multislice computed tomography (MSCT) imaging characteristics of metanephric adenoma. Material and Methods The imaging findings in eight patients with metanephric adenoma were studied retrospectively. MSCT was undertaken to investigate tumor location, size, attenuation, cystic or solid appearance, calcification, capsule sign, and enhancement pattern. Results Tumors (mean diameter, 3.3 ± 1.0 cm) were solitary (8/8), solid (7/8) with cystic components (2/8), no calcifications (7/8), had a poorly-defined margin (8/8), were centered in the renal medulla (7/8), compressed the renal pelvis (3/8), and none had retroperitoneal lymph node metastasis. The attenuation of metanephric adenoma tumors was less or equal compared to the renal cortex or medulla on unenhanced CT (30.6 ± 2.6 vs. 36.3 ± 4.6 vs. 33.2 ± 3.9, P > 0.05), while tumor enhancement after administration of an contrast agent was lower than that of normal renal cortex and medulla during all phases (P < 0.05). Conclusion Metanephric adenoma tends to be a solitary, poorly defined margin, isodense or hypodense mass arising from the renal medulla with enhancement less than the cortex and medulla during all phases.

The MSCT and MRI findings of collecting duct carcinoma

AIM To characterize the multi-section computed tomography (MSCT) and magnetic resonance imaging (MRI) features of collecting duct carcinoma (CDC). MATERIALS AND METHODS Twenty patients with CDC were studied retrospectively using MSCT (n = 20), and MSCT and MRI (n = 5). MSCT and MRI were undertaken to investigate tumour location, size, radiodensity, cystic or solid appearance, calcification, capsule, signal, enhancement pattern, and metastases. RESULTS Tumours (mean diameter 3.6 ± 1.7 cm) were solitary (20/20), solid (18/20), had cystic components (12/20), calcifications (12/20), poorly defined (18/20), were centred in the medulla (20/20), compressed the renal pelvis (12/20), and had lymph node metastases (2/20). On unenhanced computed tomography (CT), the radiodensity of the CDC was greater than that of the normal renal cortex or medulla (43.8 ± 2.4 versus 37.6 ± 5.1 or 32.6 ± 4.1, p = 0.041, n = 20). Five patients with CDC underwent MRI, which revealed cystic components (4/5), poorly defined CDC (5/5), and none of the patients had lymph node metastasis. The CDC was isointense on T1-weighted imaging, and iso- or hypointense on T2-weighted imaging. Enhancement was lower within the CDC than the renal cortex and medulla during all enhanced phases (p = 0.032, 0.001, 0.018, respectively, n = 20). CONCLUSION CDC should be considered when a renal tumour is centred in the medulla, with increased radiodensity on unenhanced CT and reduced enhancement compared to the adjacent cortex or medulla.

Comparative study of intestinal tuberculosis and primary small intestinal lymphoma

AIM To characterize the clinical, radiological, endoscopic and pathological features of intestinal tuberculosis (ITB) and primary small intestinal lymphoma (PSIL). METHODS This was a retrospective study from February 2005 to October 2012 of patients with a diagnosis of ITB (n = 41) or PSIL (n = 37). All patients with ITB or PSIL underwent computed tomography (CT) and pathological examination. Thirty-five patients with ITB and 32 patients with PSIL underwent endoscopy. These patients were followed for a further 18 mo to ascertain that the diagnosis had not changed. Clinical, endoscopic, CT and pathological features were compared between ITB and PSIL patients. RESULTS Night sweating, fever, pulmonary TB and ascites were discovered significantly more often in ITB than in PSIL patients (P < 0.05), however, abdominal mass, hematochezia and intestinal perforation were found significantly more frequently in PSIL than in ITB patients (P < 0.05). Ring-like and rodent-like ulcers occurred significantly more often in ITB than in PSIL patients (P < 0.05), however, enterorrhagia and raised lesions were significantly more frequent in PSIL than in ITB patients (P < 0.05). The rate of granuloma was significantly higher in ITB than in PSIL patients (87.8% vs 13.5%, χ(2) = 43.050, P < 0.05), and the incidence of confluent granulomas with caseous necrosis was significantly higher in ITB than in PSIL patients (47.2% vs 0.0%, χ(2) = 4.034, P < 0.05). Multi-segmental lesions, mural stratification, mural gas sign, and intestinal stricture were more frequent in ITB than in PSIL patients (P < 0.05), however, a single-layer thickening of bowel wall, single segmental lesions, and intussusception were more common in PSIL than in ITB patients (P < 0.05). Necrotic lymph nodes, comb sign and inflammatory mass were more frequent in ITB than in PSIL patients (P < 0.05). The bowel wall enhancement in ITB patients was greater than that in PSIL patients (P < 0.05), while the thickening and lymph node enlargement in PSIL patients were higher than those in ITB patients (P < 0.05). CONCLUSION Combined evaluation of clinical, radiological, endoscopic and pathological features is the key to differentiation between ITB and PSIL.

The CT and MRI observations of small cell neuroendocrine carcinoma in paranasal sinuses

BackgroundPrimary small cell neuroendocrine carcinoma (SNEC) of paranasal sinuses is an extremely rare malignant tumor known for its aggressive clinical behavior.MethodsNineteen patients with SNEC in paranasal sinuses by magnetic resonance imaging (MRI) (n = 19) and computerized tomography (CT) and MRI (n = 18) were retrospectively studied. CT and MRI were undertaken to investigate tumor features.ResultsThe lesions were located in the ethmoidal sinus (n = 6), maxillary sinus (n = 4), and bilateral sphenoid sinus (n = 9). All lesions showed a symmetry or ‘pigeon’ pattern in the bilateral sphenoid sinus (n = 9). On CT scan, the lesions showed to be isodense (n = 3) or mild hyper-dense (n = 15). Bone changes included bony absorption or sclerosis (n = 3) and moth-eaten bone destruction (n = 16). Mild cystic components were visible in five patients with SNEC. There was no evidence of calcification in any of the SNEC tumors. The lesions were isointense on T1WI and isointense (n = 6) or mild hyper-intense on T2WI (n = 13). The lesions showed mild or moderate homogeneous enhancement after the administration of a contrast agent. The aggressive nature of the tumors was demonstrated by invasion of adjacent structures, which showed involvement of the nasal cavity (n = 17), orbits (n = 15), pterygopalatine fossa (n = 9), ethmoidal sinus and sphenoid (n = 5), clivus ossis occipitalis (n = 2), cavernous sinus and internal carotid canal (n = 5), optic canal (n = 3), jugular fossa (n = 2), anterior fossa (n = 2), apex partis petrosae ossis temporalis (n = 3), meninges (n = 2), temporal fossa and infratemporal fossa (n = 4), and pharyngonasal cavity and parapharyngeal space (n = 3). There was evidence of distant metastasis in five (lung) and one (liver) of the tumors. Fifteen patients (15/19, 78.9%) expired within 5 years of the initial diagnosis, and the other patients are currently still alive.ConclusionsA tumor exhibiting mild or moderate homogeneous enhancement together with a symmetry or ‘pigeon’ pattern in the bilateral ethmoidal sinus may be considered as specific MRI features.

Value of intravoxel incoherent motion in assessment of pathological grade of clear cell renal cell carcinoma

Background Intravoxel incoherent motion (IVIM) can provide a unique view of tissue perfusion without the use of exogenous contrast agents. Purpose To investigate the value of IVIM in assessing grades of clear cell renal cell carcinoma (CRCC). Material and Methods A total of 107 patients with pathologically proven CRCC were included, 26 with grade I, 27 with grade II, 25 with grade III, and 29 with grade IV. These tumors were divided into low (I + II) and high grades (III + IV). Nine b values (0, 30, 50, 80, 150, 300, 500, 800, and 1500 s/mm2) were used in diffusion-weighted imaging (DWI). The tissue diffusivity (D), pseudodiffusivity (D*), and perfusion fraction (f) were calculated using bi-exponential fitting of the diffusion data. Results The D values of the four groups were 1.83 ± 0.38, 1.23 ± 0.19, 1.07 ± 0.26, and 0.37 ± 0.11 × 10–3 mm2/s (P < 0.05). The D* values of the four groups were 0.079 ± 0.021, 0.053 ± 0.019, 0.047 ± 0.022, and 0.033 ± 0.017 (P < 0.05). The f values of the four groups were 0.208 ± 0.09, 0.341 ± 0.12, 0.373 ± 0.15, and 0.461 ± 0.17 (P < 0.05). Both the D and D* values correlated negatively with CRCC grading (r = –0.677 and –0.693, P < 0.05). The f values correlated positively with CRCC grading (r = 0.699, P < 0.05). The areas of the D, D*, and f values under the ROC curves to diagnose low and high CRCC grades were 0.934, 0.837, and 0.793, respectively. The cutoff values of D, D*, and f were 1.13, 0.056, and 0.376, respectively; the diagnostic performance for low and high CRCC grading had a sensitivity of 82.0%, 80.7%, and 83.2% and a specificity of 90.8%, 86.3%, and 82.6%. Conclusion IVIM may provide information for differentiating CRCC grades.

Imaging features of primary renal lymphoma

Background Cases of primary renal lymphoma (PRL) are quite rare and are often mistaken for renal cell carcinoma. Purpose To determine the multislice computed tomography (MSCT) and magnetic resonance imaging (MRI) characteristics of PRL. Materials and Methods Twenty-three patients with PRL were identified by CT and MRI, and their tumor characteristics were assessed. Results Tumors exhibited single or multifocal nodules (n = 19) and diffuse renal enlargement (n = 4). Twenty-two tumors exhibited an infiltrative appearance. There was no evidence of calcification in any of the cases. Twenty-one tumors displaced or wrapped around abdominal vessels rather than encasing them. Enlarged retroperitoneal nodes were observed in three cases. Neither extension into the venous system nor distant metastasis was found. Tumor enhancement was of low attenuation compared with that of normal renal cortex and medulla (P < 0.05). PRL was isointense on T1-weighted imaging, slightly hypointense on T2-weighted imaging and hyperintense on diffusion-weighted imaging. Twenty-two patients exhibited biopsy-confirmed PRN. There were four, 12, and seven cases of low-grade, intermediate-grade, and high-grade tumors, respectively. Patient were followed up over 16 to 166 months. Six patients died within three years and five patients died within five years. Conclusion Infiltrative appearance and tumor displacement or extension around abdominal vessels rather than vessel encasement are common findings on CT or MRI imaging and may suggest a diagnosis of PRL.

CT and MRI imaging features and long-term follow-up of adult Wilms' tumor.

Background Only few previous case reports have been found focusing on the imaging findings of adult Wilms’ tumor (WT). Purpose To characterize multislice computed tomography (MSCT), magnetic resonance imaging (MRI) characteristics, and follow-up results of adult WT. Material and Methods Sixteen patients with WT were studied retrospectively. MSCT and MRI were undertaken to investigate the tumor characteristics. Results Tumors (mean diameter, 13.1 ± 4.5 cm) exhibited an expansible appearance and disrupted the reniform contour (16/16), cystic components (16/16), curvilinear calcification (1/16), poorly marginated (2/16), hemorrhage (16/16), displacement of renal pelvis or calyx (13/16), and had lymph node or distal metastases (5/16). Attenuation of WT was less or equal compared to renal parenchyma on unenhanced CT (P > 0.05), while tumor enhancement after administration of a contrast agent was lower than that of normal renal parenchyma (P < 0.05). WT was isointense on T1-weighted (T1W) imaging, isointense or hypointense on T2-weighted (T2W) imaging. Tumor enhancement was less than normal renal cortex in all phases (P < 0.05). The number of tumor stages (grades I, II, III, and IV) was two, three, six, and five cases, respectively. Follow-up time was in the range of 19–123 months; six patients died within 3 years, six patients died within 5 years after the initial diagnosis, with the remaining patients still alive. Conclusion Adult WT tends to be a large tumor, isointense or hypointense on T2W imaging with enhancement less than normal renal parenchyma in all phases. The long-term follow-up results demonstrated the poor prognosis of the tumor.

Comparative study of CT appearances in mucinous tubular and spindle cell carcinoma and collecting duct carcinoma of the kidney.

OBJECTIVE To characterize the multidetector CT (MDCT) imaging characteristics of mucinous tubular and spindle cell carcinoma (MTSCC) and collecting duct carcinoma (CDC) of the kidney. METHODS 21 patients with MTSCC and 18 patients with CDC were studied retrospectively. MDCT was undertaken to investigate differences in tumour characteristics. RESULTS Five patients with MTSCC had calcifications as did nine patients with CDC (p = 0.108). In three patients with MTSCC and four patients with CDC, the tumours had a clear boundary (p = 0.682). No patient with MTSCC had retroperitoneal lymph node metastasis as did five patients with CDC (p = 0.015). 16 patients with MTSCC showed homogeneous enhancement, whereas 11 patients with CDC showed heterogeneous enhancement (p = 0.025). The attenuation value of CDC tumours was greater than that of MTSCC and normal renal parenchyma on an unenhanced CT (p = 0.027). MTSCC and CDC tumour enhancement was less than the normal renal cortex and medulla in all phases (p < 0.001). Tumour enhancement was greater for CDC than that for MTSCC in all phases (p = 0.011, p = 0.006 and p = 0.052). CONCLUSION Unenhanced and dynamic MDCT may aid in diagnosis and differentiation of MTSCC and CDC of the kidney. ADVANCES IN KNOWLEDGE This is the first series evaluating the imaging findings of MTSCC and CDC of which we are aware, and identification of such findings may improve diagnosis of these two rare tumours.