Imaging of benign and malignant soft tissue masses of the foot

The foot is a relatively uncommon site of neoplastic and non-neoplastic soft tissue tumors. Although it contains a relatively small amount of somatic soft tissue elements, the foot is considerably rich in tendons, fasciae, retinaculae, and synovium. Corresponding to this distribution of soft tissue elements, some soft tissue lesions, such as giant cell tumor of tendon sheath, fibromatosis, and synovial sarcoma, are commonly seen in this location. Vascular tumors represent common soft tissue masses of the foot as well. Magnetic resonance imaging is the modality of choice in the assessment of soft tissue tumors. The presence of a suspected lesion can be confirmed and tumor margins can be defined accurately. In general, MRI does not provide histologic specificity, but considering some MR features may often help in correctly distinguishing benign from malignant lesions. In addition, characteristic features of the most common benign tumors (i.e., fibromatosis, cavernous hemangioma) and reactive processes of the foot (ganglion cyst, Morton's neuroma) often suggest a specific diagnosis. Electronic Publication     

Embolization of benign and malignant bone and soft tissue tumors of the extremities

PURPOSE: To reveal the effectiveness and reliability of preoperative, curative, and palliative embolization of benign and malignant bone and soft tissue tumors of the extremities. MATERIALS AND METHODS: Diagnostic angiography was performed on 35 patients (14 females, 40%; 21 males, 60%) between 6 and 70 years of age (mean, 32 years) who were referred to our digital subtraction angiography (DSA) unit between March 2000 and March 2004, and had extremity bone or soft tissue tumors. Among 17 patients who were initially assessed to be appropriate for angiographic embolization, DSA-assisted intra-arterial embolization was performed on 11 pre-operatively, and 6 curatively or palliatively. Effectiveness of the procedure was evaluated using imaging modalities, including angiography, X-ray, computed tomography, and magnetic resonance imaging as well as with post-operative findings. RESULTS: Among the 11 patients that underwent pre-operative embolization, 10 showed a significant reduction in intra-operative and early post-operative bleeding. Additionally, manipulation and excision of the tumors during surgery were easier as a result. Partial or full remission occurred in 3 of 6 patients that underwent lesion embolization. Two other patients had surgical procedures after finding their lesions had increased in size. In one patient with stable lesion size, cranial metastasis was discovered later. CONCLUSION: Pre-operative, palliative, and curative selective/superselective intra-arterial embolization is an effective and potentially developing method for benign and malignant, hypervascularized bone and soft tissue tumors of the extremities, when it is performed by an experienced team with proper embolizing agents.     

Imaging of soft tissue tumors.

In a patient presenting with a soft tissue tumor, radiographs are needed to visualize or exclude osseous involvement. Ultrasound can be used to visualize the lesion for cytologic biopsy. If cytology does not rule out sarcoma, magnetic resonance imaging is indicated to stage the lesion. As a rule staging studies other than MR imaging are not needed to evaluate the local situation. Usually MR imaging does not assist in suggesting a specific diagnosis. In certain instances, however, morphology or the presence of high signal intensity on T1, or low signal intensity on T2-weighted images increases specificity. Thick needle biopsy or open biopsy should be performed following MR imaging. This reduces sample errors and increases the accuracy of preoperative staging.     

The role of MRS in the differentiation of benign and malignant soft tissue and bone tumors

Objective

The aim of our study was to investigate the value of choline in the discrimination of benign and malignant soft tissue and bone tumors.

Materials and methods

The study group consisted of thirty subjects with bone or soft tissue tumors larger than 1.5 cm in diameter. The experiments were performed in a 1.5 T MR scanner. Coils were selected according to specific locations. A single-voxel MRS was performed for three different TE (time to echo) (31, 136, 272 ms). The volume of interest was positioned on the brightest enhancement. The presence of a cholin peak on at least 2 of these spectrums was considered as the marker of malignancy. The sensitivity, specificity and accuracy of the MRS in the detection and diagnosis of malignant lesions were calculated. The reproducibility of MRS and histopathological results were tested with kappa statistics.

Results

Histopathologically, 18 (60%) of the lesions were classed as malignant whereas 12 (40%) were classed as benign. With MRS, 15 (50%) of these lesions were classed as malignant and 15 (50%) as benign. Two patients who were found spectroscopically to have malignant tumors were shown histopathologically to have benign types. Five patients with an MRS showing a benign type were classed with malignant types in histopathological examinations. MRS had a sensitivity rate of 72.2%, specificity of 83.3%, and an accuracy rate of 76.6% in detecting malignant bone and soft tissue tumors. The interrater reliability of both techniques had a kappa value of 0.533.

Conclusions

MRS may help in the differentiation of benign and malignant soft tissue and bone tumors.     

Differentiation of soft tissue benign and malignant peripheral nerve sheath tumors with magnetic resonance imaging

PURPOSE: The objective of this study was to differentiate the magnetic resonance (MR) imaging appearance of benign peripheral nerve sheath tumors (PNSTs) from that of malignant PNSTs. MATERIALS AND METHODS: Twenty-six patients who underwent MR imaging and had a histologic diagnosis of benign (schwannoma, n=16; neurofibroma, n=1) or malignant (n=9) PNST were retrospectively reviewed. The size, location, shape, margin, and signal intensities of the tumors on precontrast and gadolinium-enhanced MR imaging were analyzed. In each patient, the presence or absence of split fat, target, and fascicular signs was determined. RESULTS: The mean size of the benign PNSTs (3.4 cm, S.D.=2.5 cm) was significantly smaller than that of the malignant tumors (8.2 cm, S.D.=3.1 cm) (P<.001). Seventeen (65.4%) of the 26 tumors were spindle shaped or ovoid (12 benign and 5 malignant tumors). Contiguity with specific nerves was identified in 15 (88.2%) of the 17 benign PNSTs but in none of the malignant tumors (P<.05). Well-defined margins were noted in all 17 benign PNSTs but in only 3 (33.3%) of the 9 malignant tumors (P<.001). Five (55.6%) of the 9 malignant PNSTs but none of the benign tumors showed signal intensity change in adjacent soft tissue (P<.05). There was no significant difference in signal intensity between the benign and malignant tumors on T(1)-weighted, T(2)-weighted, and contrast-enhanced MR images. The split fat and target signs were present more frequently in the benign PNSTs than in the malignant PNSTs (P<.05).Conclusions: Benign and malignant PNSTs are often spindle shaped. Recognition of contiguity with adjacent nerves, a well-defined margin, and the presence of the split fat sign may suggest benignity. Imaging features suggestive of malignancy can be a larger size and an infiltrative margin.     

软组织韧带样纤维瘤的MRI表现

目的:探讨软组织韧带样纤维瘤的临床及MRI特点,旨在提高对本病的认识及诊断水平.方法:回顾性分析经病理证实的3例原发和4例复发软组织韧带样纤维瘤的临床和MRI资料.结果:发病年龄5～35岁,中位年龄13.3岁.发病部位:臀部4例,下肢1例,颈部1例,胸壁1例.MRI表现:T1WI与肌肉相比,呈均匀等信号4例,不均匀混杂等低信号3例;T2WI 7例均以高信号为主,其内可见斑点状低信号区域;增强扫描后病灶明显不均匀强化.结论:软组织韧带样纤维瘤的MRI表现具有一定的特征性,MRI检查能为肿瘤的定性及定位提供重要价值.     

Pathology of the most common malignant soft tissue tumors

The present article provides an overview on the main pathological criteria of the most frequent malignant soft tissue tumors. Although these malignancies are only rarely observed and amount only to approximately 1% of all malignancies, their exact morphological analysis is of importance, because different therapeutical consequences may be drawn depending on the kind of the tumor and its grade of malignancy. Also, the prognosis of soft tissue sarcomas is extremely variable but is related to the morphology. Therefore, soft tissue sarcomas should be investigated very individually. Proper information of the pathologist by the clinician of each given case is necessary for a proper histological evaluation of biopsies that must be representative. It is recommended, whenever possible to excise the total of the tumor. With regard to these aspects liposarcomas, malignant fibrous histiocytomas, rhabdomyosarcomas, leiomyosarcomas, synovial sarcomas, malignant mesenchymomas, angiosarcomas, and fibrosarcomas are discussed, and their essential properties are reported.     

Imaging in the follow-up of soft tissue tumors.

Local recurrences of aggressive soft tissue tumors are frequent and very difficult to detect clinically after surgery and radiation therapy. Ultrasound is limited because the skin is thick. On contrast-enhanced CT, both scars and recurrences increase their signal. MRI is the best technique, and the only one we presently use in the detection of recurrent tumors. We are reporting 511 follow-up examinations in 182 patients after tumor removal. All patients had histologic confirmation or at least 6 months follow-up. There were 164 malignant tumors and 18 cases of aggressive fibromatosis.     

ADC平均值及最小值在鉴别良、恶性四肢软组织肿瘤中的价值

目的:探讨ADC平均值及最小值在鉴别四肢软组织肿瘤良恶性中的价值.方法:搜集经病理证实的53例四肢软组织肿瘤患者,其中良性24例,恶性29例,53例患者均行MRI及DWI检查,分别测量病灶的ADC平均值及ADC最小值.采用独立样本t检验比较良、恶性四肢软组织肿瘤的ADC平均值及ADC最小值差异;采用受试者工作特征(RO...     

67Ga scintigram and MRI in malignant bone tumors and malignant soft tissue tumors]

We have analyzed the characteristics of 67Ga scintigram and MRI in 11 malignant bone tumors and 11 malignant soft tissue tumors. Osteosarcoma showed a high accumulation in 67Ga scintigram and low signal intensity in T1 weighted image. T2 weighted image were not characteristic. Chondrosarcoma showed medium 67Ga accumulation and low signal in T1 weighted image and high signal in T2 weighted image. Ewing sarcoma showed low accumulation in 67Ga scan and medium intensity in MRI. Malignant soft tissue tumors showed rather low 67Ga accumulation compared with malignant bone tumors. Malignant fibrous histiocytoma showed medium accumulation of 67Ga, low signal in T1 weighted image and high signal in T2 weighted image. Liposarcoma showed low 67Ga accumulation and medium signal in T1 weighted image and high signal in T2 weighted image. To summarize these characteristics, three dimensional display is demonstrated.     

Imaging and diagnostic strategy of soft tissue tumors in children

The diagnosis of a soft tissue mass in children is a common clinical situation. Most of the lesions are benign and can be treated conservatively or by non-mutilating surgery. Nevertheless, the possibility of a malignant soft tissue tumor must be systematically considered. The most frequent benign soft tissue lesions in children are vascular lesions, fibrous and fibrohistiocytic tumors and pseudotumors, whereas rhabdomyosarcomas account for 50% of all soft tissue sarcomas. A child presenting an atypical soft tissue mass should be managed by a multidisciplinary centre, and primary resection must be proscribed until a definite diagnosis has been established. The role of imaging is essential either to confirm the benign nature of the mass or to give arguments to perform a diagnostic biopsy. Clinical examination, conventional radiography and ultrasound with Doppler represent the first-line examinations and are sometimes sufficient to assess a diagnosis. In all other situations, MRI is mandatory to establish the probable nature of the lesion and to assess local extension.     

Detection of malignant soft tissue tumors in bone imaging

A total of 2530 consecutive bone scans were examined to evaluate the number and the type of soft tissue neoplasms detected with bone-seeking phosphonates. Sixty-eight primary or secondary soft tissue neoplasms of 63 patients accumulated ^99mTc-methylene diphosphonate and 2 accumulated ^99mTc-diphosphonate, and one metastasis was seen as a nonactive cold focus in the urinary bladder. The localization of tumors was: 19 in the lung, 15 in the liver, 11 in the kidney, 10 in the peritoneal cavity or ascites, 5 in the large bowel, 4 in the vascular or lymphatic system, 3 in the connective tissue or muscles, 2 in the ovary, 1 in the urinary bladder, and 1 in the brain. Our results differ in many respects from those reported in the literature. The causes of the differences are discussed.     

Detection of malignant soft tissue tumors in bone imaging

A total of 2530 consecutive bone scans were examined to evaluate the number and the type of soft tissue neoplasms detected with bone-seeking phosphonates. Sixty-eight primary or secondary soft tissue neoplasms of 63 patients accumulated 99mTc -methylene diphosphonate and 2 accumulated 99mTc -diphosphonate, and one metastasis was seen as a nonactive 'cold' focus in the urinary bladder. The localization of tumors was: 19 in the lung, 15 in the liver, 11 in the kidney, 10 in the peritoneal cavity or ascites, 5 in the large bowel, 4 in the vascular or lymphatic system, 3 in the connective tissue or muscles, 2 in the ovary, 1 in the urinary bladder, and 1 in the brain. Our results differ in many respects from those reported in the literature. The causes of the differences are discussed.     

软组织肿瘤良恶性鉴别的术后标本~1H-MRS研究

目的：探讨术后标本1H-MRS鉴别软组织肿瘤良恶性的意义。方法：29例软组织肿瘤术后新鲜标本行常规MRI及1H-MRS测量,比较良、恶性肢体软组织肿瘤在1H-MRS代谢物胆碱（Cho）、肌酸（Cr）、三甲胺（TMA）、N-乙酰天门冬胺酸（NAA）、细胞内脂质IMCL（Lip1）、细胞外脂质EMCL（Lip2）相对浓度（即代谢物峰下平均面积）及Cho/Cr、TMA/Cr、NAA/Cr、Lip1/Cr、Lip2/Cr相对浓度比值,进行差异的t检验。结果：良性软组织肿瘤共11例,各代谢物相对浓度比值之均值分别为TMA/Cr1.02±0.50,Cho/Cr0.98±0.60,NAA/Cr0.46±0.34,Lip1/Cr7.88±6.23,Lip2/Cr5.72±4.46。恶性软组织肿瘤共18例,各代谢物相对浓度比值之均值分别为TMA/Cr2.47±1.04,Cho/Cr2.02±0.72,NAA/Cr0.41±0.39,Lip1/Cr1.41±1.31、Lip2/Cr1.01±0.93。本组资料用于诊断的恶性软组织肿瘤的TMA/Cr、Cho/Cr的阈值分别为1.19和1.21,其准确度分别为96.3%和88.9%,其诊断准确性均位于较高水平。用于诊断的良性软组织肿瘤的Lip1/Cr、Lip2/Cr的阈值分别为2.03和0.82,其准确度分别为90%及80%,其诊断准确性分别位于较高及中等水平。用于诊断的良性软组织肿瘤的NAA/Cr的阈值为0.035,其准确度分别为57%,其诊断价值位于较低水平。结论：Cho/Cr、TMA/Cr、Lip1/Cr、Lip2/Cr比值可作为软组织肿瘤良、恶性程度鉴别诊断的依据。     

Atypical benign lipomatous tumors in the soft tissue: radiographic and pathologic correlation

This article describes the characteristic imaging findings and correlates them with the pathology in the nonfatty regions of benign atypical lipomatous tumors, which have different findings compared with typical lipomas and well-differentiated liposarcomas. For differentiating these tumors from typical lipomas and well-differentiated liposarcomas, it may be helpful to analyze nonfatty regions in benign atypical lipomatous tumors.     

Usefulness of diffusion-weighted imaging for differentiating between desmoid tumors and malignant soft tissue tumors

Purpose

To evaluate the usefulness of diffusion‐weighted imaging (DWI) for differentiating between desmoid tumors and malignant soft tissue tumors.

Materials and Methods

Conventional MRI and DWI were performed for 8 desmoid tumors and 74 malignant soft tissue tumors. DWI was obtained with a single‐shot echo‐planar imaging sequence using a 1.5 Tesla (T) MR imager. DW images were acquired with motion‐probing gradient pulses applied along three directions (x, y, and z axes) with three b‐factors (0, 500, and 1000 s/mm²). Two observers blinded to clinical information measured three regions of interest within the solid tumor and selected a minimum apparent diffusion coefficient () in each lesion. The mean ADC of desmoid tumors was calculated and compared with that of malignant soft tissue tumors using the Mann‐Whitney U test.

Results

The mean ADC of desmoid tumors and malignant soft tissue tumors was 1.36 ± 0.48 × 10⁻³ mm²/s and 0.88 ± 0.20 × 10⁻³ mm²/s (mean ± SD), respectively. The mean ADC of the desmoid tumors was significantly higher than that of malignant soft tissue tumors (P < 0.01).

Conclusion

DWI is considered to be useful for differentiating between desmoid tumors and malignant soft tissue tumors. In the future, further investigation in a large series is necessary. J. Magn. Reson. Imaging 2011;33:189–193. © 2010 Wiley‐Liss, Inc.

     

FDG-PET for preoperative differential diagnosis between benign and malignant soft tissue masses

OBJECTIVE: To evaluate the standardized uptake value (SUV) of [(18)F]2-deoxy-2-fluoro- d-glucose at positron emission tomography (FDG-PET) for preoperative differential diagnosis between benign and malignant soft tissue masses. DESIGN: One hundred and fourteen soft tissue masses (80 benign, 34 malignant) were examined by FDG-PET prior to tissue diagnosis. The SUVs were calculated and compared between benign and malignant lesions and among different histologic subgroups which included three or more cases. RESULTS: There was a statistically significant difference in SUV between benign (1.80+/-1.42 [SD]) and malignant (4.20+/-3.16) soft tissue masses in total (P<0.0001). However, a considerable overlap in SUV was observed between many benign and malignant lesions. Liposarcomas (2.16+/-1.72) and synovial sarcomas (1.60+/-0.43) did not show significantly higher SUV than any benign lesions. Metastases (4.23+/-2.35) showed no statistically significant difference in SUV as compared with schwannomas (1.75+/-0.84), desmoids (2.77+/-1.32), sarcoidosis (3.62+/-1.53), or giant cell tumors of tendon sheath (GCT of TS; 5.06+/-1.63). Even malignant fibrous histiocytomas (5.37+/-1.40) could not be differentiated from sarcoidosis or GCT of TS, based on the SUV. CONCLUSIONS: A large accumulation of FDG can be observed in both benign and malignant histiocytic, fibroblastic, or neurogenic lesions. SUV at conventional FDG-PET is limited to differentiating benign from malignant soft tissue masses, when all kinds of histologic subtypes are included.     

Multiparametric quantitative analysis of tumor perfusion and diffusion with 3T MRI: differentiation between benign and malignant soft tissue tumors

Objective:To evaluate multiparametric MRI for differentiating benign and malignant soft tissue tumors.Methods:This retrospective study included 67 patients (mean age, 55 years; 18–82 years) with 35 benign and 32 malignant soft tissue tumors. Intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI)-derived parameters (D, D*, f), apparent diffusion coefficient (ADC), and dynamic contrast-enhanced (DCE)-MRI parameters (K^trans, K_ep, V_e, iAUC) were calculated. Myxoid and non-myxoid soft tissue tumors were divided for subgroup analysis. The parameters were compared between benign and malignant tumors.Results:ADC and D were significantly lower in malignant than benign soft tissue tumors (1170 ± 488 vs 1472 ± 349 µm²/s; 1132 ± 500 vs 1415 ± 374 µm²/s; p < 0.05). K^trans, K_ep, V_e, and iAUC were significantly different between malignant and benign soft tissue tumors (0.209 ± 0.160 vs 0.092 ± 0.067 min⁻¹; 0.737 ± 0.488 vs 0.311 ± 0.230 min⁻¹; 0.32 ± 0.17 vs 0.44 ± 0.28; 0.23 ± 0.14 vs 0.12 ± 0.09, p < 0.05, respectively). ADC (0.752), D (0.742), and K_ep (0.817) had high AUCs. Subgroup analysis showed that only K^trans, and iAUC were significantly different in myxoid tumors, while, ADC, D, K^trans, K_ep, and iAUC were significantly different in non-myxoid tumor for differentiating benign and malignant tumors. D, K_ep, and iAUC were the most significant parameters predicting malignant soft tissue tumors.Conclusion:Multiparametric MRI can be useful to differentiate benign and malignant soft tissue tumors using IVIM-DWI and DCE-MRI.Advances in knowledge:1. Pure tissue diffusion (D), transfer constant (K^trans), rate constant (K_ep), and initial area under time–signal intensity curve (iAUC) can be used to differentiate benign malignant soft tissue tumors.2. K^trans and iAUC enable differentiation of benign and malignant myxoid soft tissue tumors.     

Imaging benign and malignant disease of the gallbladder

This article reviews the imaging of various benign and malignant diseases of the gallbladder. Clinical findings and imaging features using ultrasound, CT, and MR for the detection and evaluation of gallstones, acute cholecystitis, xanthogranulomatous cholecystitis, adenomyomatosis, and carcinoma of the gallbladder among other disorders are discussed.