Marked Heterogeneous Enhancement Research Articles

Misdiagnosis and Delay of Diagnosis in Hemorrhagic Meningioma: A Case Series and Review of the Literature

To evaluate the clinicoradiologic characteristics of hemorrhagic meningiomas (HMs) that are missed or misdiagnosed on radiologic imaging studies. Clinical and radiologic data from 6 patients with HM who were initially misdiagnosed were collected and recorded respectively. In addition, we performed a literature review for misdiagnosed HM and summarized the results. Five of the 6 patients with misdiagnosed HM were female, and 1 was male. Both computed tomography (CT) and magnetic resonance imaging were performed in 4 patients, and CT alone was performed in 2. On CT, the HM was heterogeneously hyperdense in 5 patients and isodense in 1 patient. In all 4 patients who underwent magnetic resonance imaging, the HM was mixed iso- and hypointense on T1-weighted imaging and heterogeneously hyperintense on T2-weighted imaging. Marked heterogeneous contrast enhancement was observed in 2 patients, strong rim enhancement in 1, and peripheral enhancement in 1. The dural tail sign was seen in only 1 patient. The initial radiologic misdiagnoses were subdural hematoma (n= 1), malignant glioma (n= 1), ruptured arterial aneurysm (n= 1), metastasis (n= 2), and uncertain (n= 1). In the literature review, 22 cases of HM diagnostic error were collected. The main misdiagnoses were subdural hematoma (27.3%), traumatic hematoma (13.6%), vascular anomaly (13.6%), malignant glioma (4.5%), and metastasis (4.5%). Our study showed that in patients with HM with inadequate imaging evaluation, a small tumor associated with massive hematoma and atypical imaging features was more likely to be misdiagnosed.

Giant cell tumour of the tendon sheath of the spine: clinical features and imaging findings

ObjectivesTo review the clinical and imaging data of spinal giant cell tumour of the tendon sheath (GCTTS) to improve our understanding of the disease.MethodsThe imaging findings, clinicopathological features and clinical outcomes of 14 patients with pathologically confirmed spinal GCTTS were analysed retrospectively.ResultsAll 14 patients had a single spinal lesion, including ten cervical vertebra lesions and four thoracic vertebra lesions. CT scan findings: The lesions showed osteolytic bone destruction and were centred on the facet joint, eroding the surrounding bone with a paravertebral soft tissue mass. MRI scan findings: all the lesions manifested predominantly as isointense or hypointense on T1-weighted imaging (T1WI). On T2-weighted imaging (T2WI), eight lesions were hypointense, and four were isointense. The remaining two lesions showed slight hyperintensity. The enhanced scans of eight lesions showed moderate to marked homogeneous or heterogeneous enhancement. PET/CT findings: Among the five patients who underwent PET/CT, three presented lesions with well-defined, sclerotic borders, and the uptake of 18F-FDG was markedly increased. One lesion showed an ill-defined border and an uneven increase in 18F-FDG uptake with an SUVmax value of 8.9. A recurrent lesion was only found on PET/CT 45 months after surgery and the SUVmax was 5.1.ConclusionsSpinal GCTTS is extremely rare. Osteolytic bone destruction in the area of the facet joint with a soft tissue mass and hypointensity on T2WI images are indicative of the spinal GCTTS. GCTTS shows high uptake of 18F-FDG, and PET/CT is helpful in detecting recurrent lesions.

Sinonasal synovial sarcoma: evaluation of the role of radiological and clinicopathological features in diagnosis

To explore the value of radiological and clinicopathological features in the diagnosis of sinonasal synovial sarcomas (SS). Six patients with sinonasal SS were studied retrospectively using computed tomography (CT; n=6) and magnetic resonance imaging (MRI; n=4). The radiological and clinicopathological findings in this series were reviewed. Three lesions were located, in both the nasal cavity, and the paranasal sinuses; one was located in the nasal cavity and nasopharynx, and the remaining two were located restrictively within the nasal cavity. An aggressive nature (invasion of adjacent structure) was found in four cases. At CT, lesions were found with isodensity with calcification mainly in the peripheral areas. Bony changes were visible in all cases. Five cases showed marked heterogeneous enhancement, and three cases contained necrotic or cystic areas. At MRI, haemorrhage was observed in three cases. All cases demonstrated the "triple sign", and two high-grade SS showed a "cobblestone-like" appearance on T2-weighted imaging (WI). All time-signal intensity curves (TICs) were of the washout type. The mean apparent diffusion coefficient (ADC) values of the two high-grade cases were lower than those of the low-grade or intermediate-grade cases. Histopathologically, all but one was of the monophasic type. During the 8-40 month period of follow-up, recurrence occurred in four cases. A sinonasal tumour exhibiting characteristic calcification and bony change, together with haemorrhage, "triple sign" or "cobblestone-like" appearance, should engender a diagnosis of SS.

Small Cell Neuroendocrine Carcinoma of Paranasal Sinuses: Radiologic Features in 14 Cases.

PurposeThe purpose of this study was to explore the characteristic computed tomography (CT) and magnetic resonance (MR) features of small cell neuroendocrine carcinoma (SNEC) of paranasal sinuses.Materials and MethodsComputed tomography (n = 8) and MR (n = 14) images and clinical findings from 14 patients with SNEC of paranasal sinuses were retrospectively reviewed.ResultsEight lesions were located in the ethmoidal sinus, 4 in the maxillary sinus, and 2 in the sphenoid sinus. Small cell neuroendocrine carcinoma of the sphenoid sinus showed bilateral asymmetry patterns. On CT images, bony changes were visible in all 8 cases. On MR, 4 cases contained hemorrhage, and 10 cases contained cystic or necrotic areas. All cases demonstrated marked heterogeneous enhancement, with half showing a “cribriform-like” or “geographic” appearance. The nasal cavity was the most common site invaded by SNEC of paranasal sinuses, followed by the orbits. A time-signal intensity curve examination showed a washout-type pattern in all but 1 case. The mean ± SD apparent diffusion coefficient value was 0.702 ± 0.112 (×10−3 mm2/s). According to the Dulguerov staging system, 9 tumors were staged as N0 (1 T1, 1 T2, 5 T3, and 2 T4). The recurrence rate was 64.3%.ConclusionsSome characteristics of radiological findings can provide important clues for preoperative diagnosis.

Computed tomography and magnetic resonance imaging of adenoid cystic carcinoma in the maxillary sinus: a retrospective study with radiologic-histopathologic correlations

The aim of this study was to investigate computed tomography (CT) and magnetic resonance imaging (MRI) findings in adenoid cystic carcinoma (ACC) in the maxillary sinus and their correlations with the tubular, cribriform, and solid histopathologic types of ACC. Twenty cases of histopathologically proven ACC in the maxillary sinus were retrospectively reviewed. CT and MRI findings were correlated with histopathologic results. On CT, significant differences were discovered among the 3 histopathologic ACC types in range, size, shape, margins, type of bone destruction, and time intensity curve (TIC) (P ≤ .018). Tubular lesions were limited in range, were smaller than the other types, produced small cystic patterns with well-defined margins, and caused a cribriform pattern of bone destruction. All tumors demonstrated heterogeneous intensity signal on T1- and T2-weighted images (T1WI and T2WI) and appeared as hypo- or isointense small cystic lesions on T1WI and hyperintense on T2WI (n=6). Postcontrast MRI revealed marked heterogeneous enhancement for all lesions. The TIC showed a rapidly enhancing and slow washout pattern in all tubular lesions and a rapidly enhancing and rapid washout pattern in solid tumors. Different histologic patterns of ACCs have distinctive radiologic features, which can facilitate accurate preoperative diagnosis.

MRI findings, including diffusion-weighted imaging, in seven cats with nasal lymphoma and two cats with nasal adenocarcinoma.

Primary nasal tumours in cats are rare, with lymphoma being the most common feline nasal tumour, followed by adenocarcinoma. Although CT can reliably detect feline nasal tumours, there are no specific CT features that identify each tumour type. To our knowledge, there have been no reports describing MRI findings, including diffusion-weighted imaging (DWI), for nasal lymphomas and adenocarcinomas in cats. Therefore, this retrospective study aimed to evaluate the MRI findings of nasal lymphoma and adenocarcinoma, including qualitative and quantitative analysis of DWI. MRI examination was performed on seven cats with histologically confirmed lymphoma and on two with adenocarcinoma. The MRI protocol included T2-weighted imaging (T2WI), T1-weighted imaging (T1WI) and DWI. Apparent diffusion coefficient (ADC) values were measured using DWI. Contrast agent was not used in one cat with lymphoma. Of the cats with lymphoma, three (43%) were iso- and hyperintense on T2WI, seven (100%) were isointense on T1WI, five (83%) exhibited mild heterogeneous enhancement, including a prominent region of non-enhancement on post-contrast T1WI, and seven (100%) cats exhibited hyperintensity on DWI. The median ADC values were 0.45 × 10-3 mm2/s (range 0.37-0.53 × 10-3 mm2/s). For adenocarcinoma, two (100%) were iso- and hyperintense on T2WI, two (100%) were isointense on T1WI, two (100%) exhibited marked heterogeneous enhancement on post-contrast T1WI and two (100%) were isointense on DWI. The median ADC values were 1.08 × 10-3 mm2/s (range 0.88-1.27 × 10-3 mm2/s). The median ADC values of lymphoma tended to be lower than adenocarcinoma (P = 0.056). Determining ADC value and tumours with a large area of non-enhancement may be helpful in differentiating nasal lymphoma from nasal adenocarcinoma.

Clinical Manifestations and Radiological Characteristics on Rosai-Dorfman Disease: A Retrospective Observational Study

Background and Objective: Rosai-Dorfman disease (RDD) are usually misdiagnosed because of rarity and nonspecific clinical and radiological features. The aim of our study is to explore the clinical and imaging characteristics of RDD to improve diagnostic accuracy. Methods: Clinical and imaging data in 10 patients with RDD were retrospectively analyzed. 7 patients were underwent CT scanning and 3 patients were underwent MR examination. Results: 8 (8/10) patients presented with painless enlarged lymph nodes (LNs) or mass. 3 cases were involved with LNs, 5 cases were involved with extra-nodal tissues, and the remaining 2 cases were involved with LNs and extra-nodal tissue simultaneously. In enhanced CT images, enlarged LNs displayed mild or moderate enhancement, and 2 cases showed heterogeneous ring-enhancement. MR features of 3 patients with extra-nodal RDD, 2 cases showed a mass located in the subcutaneous and anterior abdominal wall respectively, and 1 case showed an intracranial mass. Besides, all lesions showed high signal foci on DWI images, and were characterized by marked heterogeneous enhancement with blurred edge. The dural/fascia tail sign and dilated blood vessels could be seen around all the lesions on enhanced MRI. Radiological features of 2 cases with LN and extranodal tissue involved, one case presented with the swelling and thickening of pharyngeal lymphoid ring and nasopharynx, meanwhile with enlarged LNs in bilateral submandibular area, neck and abdominal cavity, and also companied with osteolytic lesion in right proximal humerus. All these LNs displayed mild and moderate enhancement on CT images. Another case showed enlarged LNs in bilateral neck accompanied with soft tissue mass in the sinuses. Conclusions: RDD occurred commonly in young and middle-aged men and presented with painless enlarged LNs or mass.RDD had a huge diversity of imaging findings, which varied with different location. The radiological features, such as small patches of high signal foci in the masses on DWI images, heterogeneous enhancement and blood vessels around the masses, are helpful in diagnosis of extranodal RDD.

Clinical Manifestations and Radiological Characteristics on Rosai-Dorfman Disease: A Retrospective Observational Study

Background and Objective: Rosai-Dorfman disease (RDD) are usually misdiagnosed because of rarity and nonspecific clinical and radiological features. The aim of our study is to explore the clinical and imaging characteristics of RDD to improve diagnostic accuracy. Methods: Clinical and imaging data in 10 patients with RDD were retrospectively analyzed. 7 patients were underwent CT scanning and 3 patients were underwent MR examination. Results: 8 (8/10) patients presented with painless enlarged lymph nodes (LNs) or mass. 3 cases were involved with LNs, 5 cases were involved with extra-nodal tissues, and the remaining 2 cases were involved with LNs and extra-nodal tissue simultaneously. In enhanced CT images, enlarged LNs displayed mild or moderate enhancement, and 2 cases showed heterogeneous ring-enhancement. MR features of 3 patients with extra-nodal RDD, 2 cases showed a mass located in the subcutaneous and anterior abdominal wall respectively, and 1 case showed an intracranial mass. Besides, all lesions showed high signal foci on DWI images, and were characterized by marked heterogeneous enhancement with blurred edge. The dural/fascia tail sign and dilated blood vessels could be seen around all the lesions on enhanced MRI. Radiological features of 2 cases with LN and extranodal tissue involved, one case presented with the swelling and thickening of pharyngeal lymphoid ring and nasopharynx, meanwhile with enlarged LNs in bilateral submandibular area, neck and abdominal cavity, and also companied with osteolytic lesion in right proximal humerus. All these LNs displayed mild and moderate enhancement on CT images. Another case showed enlarged LNs in bilateral neck accompanied with soft tissue mass in the sinuses. Conclusions: RDD occurred commonly in young and middle-aged men and presented with painless enlarged LNs or mass.RDD had a huge diversity of imaging findings, which varied with different location. The radiological features, such as small patches of high signal foci in the masses on DWI images, heterogeneous enhancement and blood vessels around the masses, are helpful in diagnosis of extranodal RDD.

Computed tomography and magnetic resonance imaging features of cervical chordoma

Computed tomography (CT) and magnetic resonance imaging (MRI) scans of 11 patients with histologically proven cervical chordoma were retrospectively evaluated. Imaging features assessed included location, morphology, association with adjacent structures, vertebral destruction, status of cortical bone, periosteal reaction, attenuation and calcification by CT, and signal intensity and enhancement pattern by MRI. Of 7 cases with CT, 6 exhibited lytic-sclerotic bone destruction. A total of 5 cases exhibited pressure erosion of outer cortex, 3 of which had spiculated periosteal reaction. Calcification was observed in 3 cases. All cases were heterogeneous and hypodense. MRI T2-weighted images (n=10) revealed heterogeneous hyperintense (n=5), intermediate (n=2) and intermediate-hyperintense signal intensity (n=3). Hypointense septa between lobules (n=5) and stripes (n=3) were observed on T2-weighted images. Post-contrast magnetic resonance images (n=6) demonstrated marked heterogeneous (n=3) and ring-like (n=3) enhancement. CT scanning is valuable in revealing the lytic-sclerotic bone destruction, pressure erosion of outer cortex and calcification. MRI is useful in demonstrating the results of soft tissue mass. The two examinations are necessary for differential diagnosis of patients with suspected cervical chordoma.

Lymphadenitis associated with cat-scratch disease simulating a neoplasm: Imaging findings with histopathological associations.

The lymphadenitis associated with cat-scratch disease (CSD) is often confused with neoplasms by a number of radiologists and clinicians, and consequently, unnecessary invasive procedures or surgeries are performed. In the present study, the contrast-enhanced computed tomography (CT) and magnetic resonance imaging (MRI) findings of 10 patients (6 men and 4 women) with clinically and pathologically confirmed lymphadenitis associated with CSD were retrospectively analyzed (CT in 3 patients, MRI in 6 patients, and CT and MRI in 1 patient) at The Second Affiliated Hospital of Zhejiang University School of Medicine (Hangzhou, China) between January 2007 and November 2014. As a result, 17 enlarged lymph nodes were identified in 10 cases. The 5 nodes identified by CT scan exhibited relatively inhomogeneous isodensity to muscle, with patchy low density in the center. All 14 nodes identified by MRI scan exhibited homogeneous or heterogeneous isointensity to muscle or slightly increased intensity compared with that of muscle on T1-weighted images (T1WI), and homogeneous or heterogeneous hyperintensity on fat-suppressed T2WI. Following enhancement, all 17 enlarged lymph nodes associated with CSD demonstrated the following 3 different enhancement patterns: Moderate homogeneous enhancement (n=8), which was associated with histologically identified early disease stage; marked heterogeneous enhancement with no enhancement of the necrotic areas (n=4), and heterogeneous enhancement with progressively ‘spoke-wheel-like’ (defined as radiating enhancement from the center) enhancement of the patchy low-density area (n=1), which was associated with histologically identified intermediate disease stage; and astral low-density/hypointensity with marked enhancement (n=2) or a ‘rose flower’ sign (n=2), which was associated with histologically identified late disease stage. We hypothesized that the CT and MRI results of lymphadenitis in CSD may be associated with the pathological features. It may be suggested that the diagnosis of CSD may be formed when considering the characteristic CT and MRI features of astral low-density/hypointensity with marked enhancement or a ‘rose flower’ sign (defined as marginal petaloid enhancement) in the late disease stage, or the MRI results of homogeneous, moderate enhancement in the early disease stage, or the CT/MRI data of heterogeneous enhancement with non-enhancing area in the center in the intermediate disease stage, in solitary or multiple enlarged lymph nodes associated with general subcutaneous edema in the vicinity of the nodes on CT/MRI and with a history of cat exposure.

Clinical and imaging features of subependymal giant cell astrocytoma: report of 20 cases

BackgroundSubependymal giant cell astrocytoma (SEGA) is a clinically benign brain tumor associated with tuberous sclerosis complex (TSC). There are still controversies on early diagnosis of the tumor.MethodsCT and MR imaging of 20 patients with pathologically confirmed SEGA were retrospectively reviewed. Two radiologists evaluated the location, shape, size, number, edge, cerebral edema, homogeneous or heterogeneous appearance, attenuation and signal intensity, degree of enhancement and calcification of lesions. Their prognoses were based on clinical observations.ResultsSEGA showed similar features in imaging: an extra-axial, well-circumscribed, periventricular mass, isodense or slightly hyperdense on CT, hypointensity on T1-weighted imaging and isointensity to hyperintensity on T2-weighted imaging. The mass enhanced markedly and heterogeneously after the administration of contrast agent. Subependymal nodules were demonstrated in 5 cases. Remarkably, 17 patients (85%) showed ventricular dilatation and 14 patients (70%) showed calcification in CT and MR imaging. Moreover, perifocal edema was not significantly near the masses. Four cases are associated with tuberous sclerosis complex (TSC).ConclusionsAlthough there are no pathognomonic imaging findings for SEGA, the following clinical and imaging features might be helpful for the diagnosis, such as the initial age of first or second decade, typical location in the periventricular regions adjacent to the foramen of Monro, hydrocephalus accompanied with raised intracranial pressure, TSC and marked heterogeneous enhancement.

Sinonasal Angiomatous Polyp: Evaluation With 2-Phase Helical Computed Tomography.

Sinonasal angiomatous polyp (SAP) is a rare benign nontumorous lesion and previously considered lack of characteristic computed tomography (CT) findings. This study aimed to evaluate 2-phase helical CT for characterization of SAP.Twelve patients with pathologically confirmed SAP underwent 2-phase helical CT preoperatively. After injection of 80 mL contrast material at a rate of 3 mL/s, early and delayed phases were obtained with delays of 30 and 120 s, respectively. The degree and pattern of enhancement were visually analyzed. The attenuation changes were also analyzed quantitatively by measuring CT values and compared with those of the internal maxillary artery (IMA).All 12 cases showed vessel-like marked heterogeneous enhancement at both early and delayed phases. An irregular linear, nodular, and patchy enhancement pattern was found at the early phase, and enlarged and fused together, that is, progressive enhancement pattern was found at the delayed phase. There was no significant difference between the CT values of SAP and those of the IMA at the plain, arterial phase, and delayed phase (53 ± 6 Hounsfield units [HU] vs 56 ± 7 HU, 187 ± 56 HU vs 209 ± 71 HU, and 143 ± 22 HU vs 139 ± 19 HU, respectively, P = 0.361, 0.429, and 0.613, respectively).Vessel-like marked heterogeneous enhancement was a characteristic CT feature of SAP, and progressive enhancement on 2-phase helical CT could further convince the diagnosis.

Radiological and clinical findings of osseous peripheral primitive neuroectodermal tumors.

Peripheral primitive neuroectodermal tumor (pPNET) is a rare and highly malignant undifferentiated type of tumor. The aim of the present study was to analyze the computed tomography (CT), magnetic resonance imaging (MRI) and clinical findings of osseous pPNET. The present study retrospectively analyzed the clinical data and CT findings from 15 patients with osseous pPNET; the MRI findings from 11 of these 15 patients were confirmed by histopathological examination. The 15 patients included 9 men and 6 women. The mean patient age was 29 years (range, 16-64 years) and 11 cases were aged <30 years. A CT scan was performed in 15 cases and the findings included a lytic lesion (13 cases), a lytic lesion with irregular sclerosis and dilation (2 cases), a soft tissue mass (15 cases), calcification (2 cases) and periosteal reaction (5 cases). A total of 9 cases of soft tissue mass were heterogeneous, with different sizes of lower-density necrotic areas. An enhanced MRI scan was performed in 11 cases. On T1-weighted images (WI), the soft tissue mass was isointense (8 cases) and marginally hyperintense (3 cases). On T2WI, aggressive soft tissue masses were heterogeneous iso- or hyperintense (11 cases). On contrast-enhanced T1WI, marked heterogeneous enhancement was present in 10 cases and intermediate heterogeneous enhancement in 1 case. The results indicated that osseous pPNET mainly affects male adolescents and young adults. The CT findings of osseous pPNET were destructive lesions with a soft tissue mass and, occasionally, with periosteal reaction. The tumor was often isodense, with patchy hypodense areas. Tumor calcification was uncommon. The MRI findings were those of an aggressive soft tissue mass exhibiting isointensity on T1WI and iso- or hyperintensity on T2WI, with marked heterogeneous enhancement. Although the imaging characteristics of pPNETs may be non-specific, CT and MRI may be useful in delineating the extent of the tumor, identifying distant metastases, predicting resectability and monitoring treatment.

Radiological-pathological correlation of yolk sac tumor in 20 patients.

Yolk sac tumor (YST) is a rare tumor. Familiarity of its radiological characteristics may permit preoperative diagnosis and improve surgical management of patients. However, a detailed description of the imaging features of YST with pathological correlation in particular is scarce. To investigate computed tomography (CT) findings of YSTs with pathological correlation. CT images of 20 patients with pathologically proven YST were retrospectively reviewed. The location, size, margin, internal architecture, and pattern and degree enhancement of the lesion were evaluated. Radiological findings were correlated with pathological results. The locations of 20 tumors were distributed between the testis (n = 3), ovary (n = 6), sacrococcygeal area (n = 6), rectum (n = 1), and mediastinum (n = 4). The median age was 13 years. On CT images, all tumors were seen as oval (n = 14) or irregular (n = 6), well-defined (n = 16) or ill-defined (n = 4) masses with a mean size of 9.7 cm. The lesions were solid cystic (n = 10), entirely solid (n = 6), or predominantly cystic (n = 4). Intratumoral hemorrhage, calcification, and fatty tissue were seen in nine, three, and two tumors, respectively. Discontinuity of the tumor wall was seen in eight tumors. After contrast media administration, most tumors showed heterogeneous moderate to marked enhancement (n = 7) or heterogeneous marked enhancement (n = 9). Enlarged intratumoral vessels were seen in 17 tumors. YST usually appears as a large solid-cystic mass with intratumoral hemorrhage, capsular tear, marked heterogeneous enhancement, and enlarged intratumoral vessels on CT images. Intratumoral calcification and fatty tissue, although rare, may indicate a mixed YST containing teratoma component.

The imaging features of meningeal Ewing sarcoma/peripheral primitive neuroectodermal tumours (pPNETs).

To explore the imaging features of meningeal Ewing sarcoma/peripheral primitive neuroectodermal tumours (pPNETs). The imaging features and pathological characteristics of eight cases of surgically and pathologically confirmed Ewing sarcoma/pPNET were analysed retrospectively in light of recent literature on the disease. The peak age was between 10 and 20 years. The lesions tended to be spindle shaped and dural based, usually widely so. CT showed that the lesions had slightly uneven high density in five cases and iso-low mixed density in three cases; marked heterogeneous enhancement was seen in all cases after contrast injection. MRI of the lesions showed varying proportions of isointense and hypointense signal in all cases on unenhanced T1 weighted imaging and varying proportions of isointense and hyperintense signal on T2 weighted imaging. After contrast injection, marked heterogeneous enhancement was seen in all cases; three cases showed a short and nodular dural tail and five cases showed adjacent skull erosion and osteolysis. Pathological results included high cell density, haemorrhage and necrosis. The cells resembled lymphocytes and spindle cells with transparent cytoplasm. CD99 and vimentin were expressed by all tumour cells. Features of meningeal Ewing sarcoma/pPNETs include peak incidence at 10-20 years of age, a broad connection to the meninges, a thick dural tail involved with tumour, skull and scalp erosion and early metastasis. Necrosis and cystic changes are the common histological findings. The imaging features of meningeal Ewing sarcoma/pPNETs have not been reported. The study helps to identify meningeal Ewing sarcoma/pPNETs and meningioma.

Solitary fibrous tumours in the extracranial head and neck region: correlation of CT and MR features with pathologic findings.

Solitary fibrous tumours (SFTs) are rare, mesenchymal neoplasms. The purpose of this study was to analyse the radiological and clinicopathological features of SFTs in the extracranial head and neck region. We retrospectively reviewed the clinical, computed tomography (CT), magnetic resonance imaging (MRI), and pathological features in 18 patients (12 men and 6 women), aged 18-75years, with histologically proven SFTs in the extracranial head and neck region. Fourteen patients underwent CT scanning and nine underwent MRI. The histological techniques included routine haematoxylin-eosin staining and immunohistochemical analysis. Clinical data were retrieved from the medical records. Most tumours presented as a slow-growing painless mass. Eighteen SFTs arose in the orbit, cheek, masticator space, the parapharyngeal space, infratemporal fossa, maxillary, submandibular space and the parotid gland, respectively. All 18 lesions were found as a solitary mass, ranging in size from 1.2 to 6.8cm (mean 3.57cm). They mostly presented with an ovoid shape, with well-defined margin, and isodensity on plain CT, isointensity on T1-weighted imaging, mild hyperintensity on T2-weighted imaging and diffusion-weighted imaging, and marked heterogeneous enhancement on contrast-enhanced CT and MRI. The time-intensity curves (TICs) exhibited a rapidly enhancing and slow washout pattern on dynamic contrast-enhanced MRI and dual-phase CT. Imaging findings of the SFTs depended on the histopathological components. SFTs most commonly present with an asymptomatic mass in adults. A solitary, ovoid and well-defined mass with strong enhancement after contrast agent injection is suggestive of this diagnosis. Rapidly enhancing and slow washout pattern TICs may be additional valuable features.

MR imaging of intracranial hemangiopericytomas

To describe the MR features of primary intracranial hemangiopericytomas (HPCs) on conventional imaging, diffusion and MR spectroscopy and aim to determinate distinguishing features from meningiomas. From 2006 to 2012, seven patients with pathologically confirmed primary intracranial HPCs were included. The clinical data, conventional MR findings (n=7), DWI features (n=7) and MR spectroscopy (n=5) were retrospectively analyzed. ADC values of the HPCs (n=7) were measured on ADC map and were compared with that of contralateral normal white matter. Of the seven HPCs, four were anaplastic HPCs (WHO grade III) and three were HPCs (WHO grade II). MR pattern consisted in lobulated or irregular margin tumors in all cases with cross-leaf growth on both side of the falx in two cases. The lesions showed mainly iso signal (n=4) on T1 WI and heterogeneous high signal (n=5) on T2 WI. Heterogenity was mainly related to intra tumoral hemorrhage (n=4), and proeminent intratumoral flow voids (n=3). Marked heterogeneous enhancement (n=5) with dural tail (n=4) was noted. All tumours showed significant peritumoral edema. ADC values of the tumor tissue component range between 0.638 and 1.50×10(-3)mm/s(2) (average=1,02). Three grade II HPCs showed higher values compared to normal parenchyma ADC (range between 0.772 and 0.930×10(-3)mm/s(2) with average of 0.830), whereas grade III HPCs showed either equal (three cases) or decreased ADC values (one case). MRS showed in all cases markedly increased Cho with lip/lac peak, decreased Cr and almost absent NAA. High mI peak with large glutamine/glutamate were noted in the three grade II HPCs. Conventional MR pattern when combined with DWI and MRS findings are highly suggestive of HPC and appear valuable data to differentiate HPCs from meningiomas.

CLINICAL AND LOW‐FIELD MRI CHARACTERISTICS OF INJECTION SITE SARCOMA IN 19 CATS

Magnetic resonance imaging (MRI) has been recommended for staging and surgical planning in cats with injection site sarcomas (ISS). The purpose of this retrospective study was to describe low-field MRI characteristics of confirmed injection site sarcomas in a group of cats. Low-field MR images, thoracic radiographs, histopathology findings, and medical records of cats that fulfilled histological criteria of injection site sarcoma were retrieved and reviewed retrospectively. Presence or absence of tumor mineralization and pulmonary metastases were recorded from thoracic radiographs. Characteristics recorded from low-field MRI studies included tumor number, volume (ellipsoid method), intensity relative to surrounding musculature, homogeneity, regions of signal void (mineralization) or cavitation, degree and pattern of contrast enhancement, tumor margination, presence of a peripheral T2W hyperintense zone, and bone contact. A total of 19 cats met inclusion criteria. Cats with multiple tumors were more likely to have had previous excisional biopsy, and were less likely to undergo definitive surgery. All tumors were hyperintense relative to surrounding musculature on T1W and T2W images. Larger tumors were more likely to exhibit mineralization (P < 0.05). Tumor volume could not predict tumor-free margins at definitive surgery. The majority of tumors showed moderate to marked heterogeneous contrast enhancement. Infiltrative margins and the presence of a peripheral T2W hyperintense zone were more prevalent following excisional biopsy, while cavitation was more prevalent following incisional biopsy. Findings indicated that low-field MRI characteristics of injection site sarcoma may vary widely and may be affected by prior incisional or excisional biopsy.

Thirty-nine cases of intracranial hemangiopericytoma and anaplastic hemangiopericytoma: A retrospective review of MRI features and pathological findings

ObjectiveTo retrospectively review the imaging features of surgically and pathologically confirmed intracranial hemangiopericytoma and anaplastic hemangiopericytoma. MethodsThirty-nine cases of surgically and pathologically confirmed hemangiopericytoma and anaplastic hemangiopericytoma were analyzed retrospectively. The MRI features were compared with pathological findings in all cases. ResultsOf the 39 cases, 21 were anaplastic hemangiopericytoma (WHO grade III) and the remaining cases were hemangiopericytoma (WHO grade II); all lesions were solitary. MRI of anaplastic hemangiopericytoma showed that 20 cases were lobulated, and nine grew cross-leaf. The lesions showed mixed iso-high-low signal (n=20) or iso-signal (n=1) on plain T1WI, and mixed high-low signal (n=20) or iso-signal (n=1) on plain T2WI. After contrast injection, marked heterogeneous enhancement was seen in 19 cases. Significant necrosis and cystic changes were seen in 16 cases, and the “dural tail sign” was found in two cases. Ten cases had bony destruction, and 16 showed significant peritumoral edema. In 18 cases of hemangiopericytoma, nine were oval-shaped and three grew cross-leaf. The lesions showed mixed iso-low signal (n=10) or iso-signal (n=8) on plain T1WI, and mixed iso-high signal (n=10) or iso-signal (n=8) on plain T2WI. After contrast injection, significant uniform enhancement was seen in 10 cases. Significant necrosis and cystic changes were seen in seven cases, and “dural tail sign” was seen in six cases. Two cases had bony destruction. No case showed significant peritumoral edema. Pathological immunohistochemical Ki67 staining showed a concentration of ∼18.4% positive cells in anaplastic hemangiopericytoma, whereas in hemangiopericytoma it was 7.12%. ConclusionImaging findings of intracranial anaplastic hemangiopericytoma had more pronounced lobulation, cross-leaf growth tendency, more and easier bleeding, more necrosis, more cystic changes giving rise to heterogeneous signals, rarer frequency of the “dural tail sign”, more damage near the skull, and more significant peritumoral edema than hemangiopericytoma. These features may help differentiate these two types of malignancy.

Primary Dedifferentiated Liposarcoma of the Axilla Arising in a Mixed, Well-differentiated and Myxoid Liposarcoma

We describe a case of mixed liposarcoma of the axilla presenting as a high grade undifferentiated sarcoma with areas of well-differentiated and myxoid liposarcoma. MRI demonstrated a lobulated, septated intermuscular mass with marked heterogeneous gadolinium enhancement. A small focus of the tumor demonstrated fat suppressed signal more characteristic of well-differentiated liposarcoma. Pathologic analysis following wide local excision revealed a large, high grade sarcomatous component with highly pleomorphic cells with a thin rim of well-differentiated and myxoid liposarcoma on histologic examination. Dedifferentiated liposarcomas arising outside of the retroperitoneum are very rare, as are dedifferentiated liposarcomas arising from a histologically mixed liposarcoma. In this regard, this case illustrates an unusual combination of tumor location and histology which, to our knowledge, has not previously been reported.