Accuracy of Preoperative MRI with Microscopy Coil in Evaluation of Primary Tumor Thickness of Malignant Melanoma of the Skin with Histopathologic Correlation

OBJECTIVE: The purpose of this study was to evaluate the accuracy of a preoperative MRI with microscopy coils in determining the primary tumor thickness of malignant melanoma with histopathologic correlation. MATERIALS AND METHODS: Eleven patients with histopathologically confirmed malignant melanoma were included in this study. MR images of the tumors were obtained with a 47-mm microscopy coil on 1.5T MR scanners and were evaluated by two radiologists, who assessed the thickness of the primary tumor on T2-weighted images (T2WI) and gadolinium-enhanced T1-weighted images with fat suppression (Gd-T1WI) and compared the results with the histopathologic findings as the reference standard. Correlations between tumor thickness on MRI and histopathologic examination were assessed using concordance correlation coefficients (CCCs). Inter- and intraobserver variabilities of tumor measurements were also assessed by intraclass correlation coefficient (ICC). RESULTS: Among the 11 cases included in the study, 10 cases from the same number of patients were managed with surgical excision and one case was confirmed with punch biopsy. The primary tumor thickness measured on T2WI showed better correlation with histopathologic results, as compared with measurements taken on Gd-T1WI: the CCC of measurements on T2WI ranged from 0.64 to 0.78, indicating a substantial agreement, whereas the CCC of measurements on Gd-T1WI ranged from 0.50 to 0.61, indicating a moderate to substantial agreement. Inter- and intraobserver agreements of readers 1 and 2 were excellent for both T2WI and Gd-T1WI, with ICC ranging from 0.86 to 0.99. CONCLUSION: MR imaging with microscopy coils may be an accurate technique in the preoperative assessment of tumor thickness in malignant melanoma, especially on T2-weighted images.

MR Imaging of Uncommon Soft Tissue Tumors in the Foot: A Pictorial Essay

A large variety of masses occur in the foot. The foot is a comparatively rare site of soft tissue neoplasms. MRI has greatly improved the ability to detect and delineate soft tissue lesions and is now considered the gold-standard imaging technique in their investigation. Recently, we have encountered rare soft tissue tumors of the foot. The presented cases include benign masses such as granuloma annulare, angiomyoma, neural fibrolipoma, and giant cell tumor of tendon sheath, as well as malignant tumors such as melanoma, synovial sarcoma, rhabdomyosarcoma and extraskeletal myxoid chondrosarcoma. We wish to illustrate the MR findings of these uncommon soft tissue tumors to aid in their diagnosis.

Nodular Fasciitis on the Nasolabial Fold in a 5-month-old Infant: A Case Report

We report the case of a 5-month-old infant with a rapidly growing mass on the right nasolabial fold; to our knowledge, this is the youngest infant diagnosed with nodular fasciitis in the literature. Based on the anatomic location, this was a subcutaneous type of nodular fasciitis and it had a mixed cellular and fibrous histologic composition, which is rare in infancy. Here we present periodic ultrasonographic images and MR images, as well as a detailed comparison of the pathologic and radiologic findings.

Ruptured Epidermal Inclusion Cyst in the Axilla: A Case Report

Epidermal inclusion cysts, the most common type of simple epithelial cyst, are typically well-encapsulated, subepidermal and mobile nodules. They may occur anywhere, but are mostly found on the scalp, face, neck, trunk, and back. Less than 10% of epidermal inclusion cysts occur on the extremities, and even fewer are found on the palms, soles, and breasts. If epidermal inclusion cysts rupture, foreign body reaction, granulomatous reaction or abscess formation could follow. We described here the sonographic findings of ruptured epidermal inclusion cyst of the right axilla in a 33-year-old woman who presented with a palpable axillary mass forming an inflammatory abscess. Address for reprints : Hak Hee Kim, M.D., Department of Radiology, Asan Medial Center, University of Ulsan, College of Medicine 388-1 Pungnap-2dong, Songpa-gu, Seoul 138-736, Korea.

A Case of Pilomatricoma in the Upper Arm: Sonographic and MR Imaging Findings

Pilomatricoma is an uncommon benign skin neoplasm arising from the hair matrix. The radiologic features of this uncommon tumor have occasionally been described in the literature however, to the best of our knowledge, there have been no reports in Korea on the sonographic and MR imaging findings of pilomatricoma involving the upper arm. In this article, we describe the imaging findings of a case of pilomatricoma involving the upper arm, with the emphasis being placed on the sonographic and MR imaging findings and a review of the literature.

Extraskeletal Ewing Sarcoma of Cervical Epidural Region: Cases Report

Extraskeletal Ewing sarcoma is a rare malignant tumor found in children and young adults. It commonly occurs in deep soft tissue of the trunk, especially in the paravertebral region and extremities. We report two cases of extraskeletal Ewing sarcoma occurring as a cervical epidural tumor in elderly patients. The MRI and CT findings showed that paravertebral epidural tumors had invaded the spinal canal through the intervertebral foramen. At T1-weighted MR imaging, the masses were isointense to muscle, and at T2* and T2-weighted images were hyperintense, and heterogeneous contrast enhancement was observed. Extraskeletal Ewing sarcoma, though quite rare, should be borne in mind in the differential diagnosis of paraspinal epidural tumors.

Dedifferentiated Liposarcoma in the Thigh: Case Report

Dedifferentiated liposarcoma occurs in less than 10% of all liposarcoma and is found most often in the retroperitoneum and extremities. Histologically, the tumor was composed of well-defferentiated liposarcomastous areas with malignant fibrous histiocytoma-like area, peculiar neurallike whirling pattern associated and focal metaplastic bone formation. The rare radiologic feature of this have not been sufficiently described in the previous literature, and we now report a case of dedifferentiated liposarcoma in the thigh.

Inflammatory Myofibroblastic Tumor of Perineal Soft Tissue: A Case Report

Inflammatory myofibroblastic tumor is a rare benign condition of unknown etiology, and it may simulate malignancy. It is composed of myofibroblast, plasma cells and histiocytes and is found in lung, the liver, orbit, skin, mesentery, retroperitoneum and maxillary sinus. We report a case of inflammatory myofibroblastic tumor of perineal subcutaneous fat in a 35-year-old woman who complained of a palpable mass. Ultrasonography revealed a well-marginated lobulated hypoechoic lesion with peripheral poorly-defined hyperechoic strands in the subcutaneous fat of the right perineum. The lesion demonstrated low signal intensity on T1-weighted images and of heterogenous high signal intensity on T2-weighted images, compared with surrounding muscle. After intravenous injection of gadolinium, it showed clear homogeneous enhancement but poorlydefined adjacent strands. The final histologic diagnosis was inflammatory myofibroblastic tumor.

Mesenchymal Chondrosarcoma Arising from the Intrascrotal Extratesticular Soft Tissue: A Case Report

Intrascrotal extratesticular malignancies are rare, and the radiologic findings of extraskeletal chondrosarcoma have not been reported. We describe the radiologic findings of a case of mesenchymal chondrosarcoma arising from intrascrotal extratesticular soft tissue and represented by a complex, cystic, solid mass containing calcifications and hematoma.

MR Findings of Angiomyoma of the Extremities: Two Cases Report

Angiomyoma is a benign soft tissue tumor that arises from the smooth muscle layer of blood vessels in the deeplayers of the dermis, or in subcutaneous tissue. It occurs as a well-encapsulated solitary mass, most of which areless than 2cm in diameter. Some patients complain of pain with or without tenderness. This tumor has apredilection for the lower extremities of middle-aged females. MRI findings of angiomyoma of the extremities haverarely been reported, and we describe these findings in two cases of angiomyoma of the hand and foot.

Benign and Malignant Musculoskeletal Tumors Evaluated with the Aid of Pa rametric Maximum Slope and Blood Volume Images

PURPOSE: To assess the values of parametric "maximum slope(MS) and blood volume(BV)" images as indicators of tissue vascularization and perfusion in distinguishing benign from malignant musculoskeletal tumors. MATERIAL AND METHODS: Dynamic inversion recovery spin-echo echo-planar imaging (TR/TE/TI/NEX: 1 5 0 0 / 2 4 / 5 00 ms/1; matrix 128 x 128; slice thickeness 5 mm, interleaved) at 1.5-second intervals(200 phases) was performed after intravenous bolus injection of Gd-DTPA. A total of 32 pathologically proven muscu-loskeletal masses(benign 9, malignant 23) were included in this study. MS was derived by fitting a time-intensity curve using a polynomial model. BV was determined by integration until maximum slope was reached. On a pixel-by-pixel basis, MS and BV images were generated and displayed by gray-scale. We selected a region of interest(ROI, more than 6 x 6 pixels) including the highest value of the tumors and calculated mean values of MS and BV. Wilcoxon's signed rank test was used to compare benign tumors with malignant pre- and postchemotherapy tumors. RESULT: The mean values of ROIs selected on MS images were significantly different (p=.008) between benign (mean 3.33, range 0.01 -16.47 ) and prechemotherapy malignant(mean 8.54, range 1.61 -16.90) tumors, as were the mean values of ROIs on BV images(p=.005; benign tumors: mean 162.17, range 91.17 -2 8 3 . 7 ; prechemotherapy malignant tumors: mean 330.18, range 117.5 -845.1). MS and BV values of benign and malignant tumors overlapped but tended to be separated. CONCLUSION: BV and MS images may help distinguish benign from malignant musculoskeletal tumors.

Benign and Malignant Musculoskeletal Tumors Evaluated with the Aid of Pa rametric Maximum Slope and Blood Volume Images

PURPOSE: To assess the values of parametric "maximum slope(MS) and blood volume(BV)" images as indicators of tissue vascularization and perfusion in distinguishing benign from malignant musculoskeletal tumors. MATERIAL AND METHODS: Dynamic inversion recovery spin-echo echo-planar imaging (TR/TE/TI/NEX: 1 5 0 0 / 2 4 / 5 00 ms/1; matrix 128 x 128; slice thickeness 5 mm, interleaved) at 1.5-second intervals(200 phases) was performed after intravenous bolus injection of Gd-DTPA. A total of 32 pathologically proven muscu-loskeletal masses(benign 9, malignant 23) were included in this study. MS was derived by fitting a time-intensity curve using a polynomial model. BV was determined by integration until maximum slope was reached. On a pixel-by-pixel basis, MS and BV images were generated and displayed by gray-scale. We selected a region of interest(ROI, more than 6 x 6 pixels) including the highest value of the tumors and calculated mean values of MS and BV. Wilcoxon's signed rank test was used to compare benign tumors with malignant pre- and postchemotherapy tumors. RESULT: The mean values of ROIs selected on MS images were significantly different (p=.008) between benign (mean 3.33, range 0.01 -16.47 ) and prechemotherapy malignant(mean 8.54, range 1.61 -16.90) tumors, as were the mean values of ROIs on BV images(p=.005; benign tumors: mean 162.17, range 91.17 -2 8 3 . 7 ; prechemotherapy malignant tumors: mean 330.18, range 117.5 -845.1). MS and BV values of benign and malignant tumors overlapped but tended to be separated. CONCLUSION: BV and MS images may help distinguish benign from malignant musculoskeletal tumors.

MR Findings of Extraabdominal Fibromatosis

PURPOSE: To evaluate the MR findings of extra-abdominal fibromatosis and the role of MRI in primary diagnosis MATERIALS AND METHODS: Fifteen cases in of histologically proven extra-abdominal fibromatosis in 13 patients were retrospectively reviewed. T1-weighted and T2-weighted images were obtained in axial, coronal and sagittal planes. Gd-enhancement was performed in 14 cases, and dynamic enhancement studies in two. All lesions were evaluated for mass shape and margin definition. RESULTS: Among the 15 cases, tumors of the buttock accounted for five, and tumor of the thigh for two. In eight cases tumors were intermuscular and in six cases were intramuscular. In ten cases (67 %) the mass extended along the long axis of the body and in 14 of 15 cases (93%) focal infiltration of adjacent structures was visible. The signal intensity of the lesion was in all cases inhomogeneous on both T1 and T2 weighted images. As seen on Gd-DTPA enhanced scans, the masses were inhomogeneously enhanced. In all cases MRI revealed star-shaped linear strands or a band-like low signal area in the mass. These features were not enhanced and were arranged along the long axis of the mass. CONCLUSION: MR findings of extra-abdominal fibromatosis were relatively characteristic and helpful for primary diagnosis of the condition.

Liposarcoma: MR Findings in the Histologic Subtypes

PURPOSE: To evaluate the MR imaging findings of liposarcomas of different histologic subtypes. MATERIALS AND METHODS: We evaluated MR images of 21 patients (5 men and 16 women, mean age, 55 years) with liposarcoma andcorrelated the findings with the results of histopathology. In the study group seven liposarcomas werewell-differentiated, seven were myxoid, three were mixed, two were pleomorphic, and one was round cell. RESULTS: On T1 -and T2 - weighted images, six of seven well-differentiated liposarcomas showed signal intensity equal tothe fat and hypointense septa, while the other showed low signal intensity on a T1 -weighted image, heterogeneoushigh signal intensity on a T2- weighted image, heterogeneous enhancement after the administration of contrastmedia and was dedifferentiate. Nine masses in seven patients with myxoid liposarcoma showed low signal intensityon T1-weighted images, six of the nine showed lace-like foci of high signal intensity. On T2 -weighted images, allmasses showed homogeneous high signal intensity. After administration of contrast media, five of seven massesshowed heterogeneous enhancement. Two of three mixed form were well-differentiated and myxoid types, and twosubtypes were separable on MR. Pleomorphic, round cell, mixed type myxoid and pleomorphic and unclassified casesshowed low signal intensity on T1-weighted images, heterogeneous high signal intensity on T2-weighted andheterogeneous enhancement. CONCLUSION: Using MR imaging, well-differentiated and myxoid liposcarcomas may bedifferentiated from other types.

Usefulness of Sonography in Detection of Local Recurrent Soft Tissue Tumors

PURPOSE: To evaluate the usefulness of ultrasonography in the diagnosis of local recurrent soft tissue tumors. MATERIALS AND METHODS: We retrospectively analysed the results of 113 sonographic examinations in 102 patients (38males, 64 females) after surgical treatment of soft tissue tumors (82 malignancies, 20 benignancies) during thelast five years. Follow-up included physical and sonographic examinations using a 5-10MHz transducer every twomonths. In 17 cases, MR images were obtained The criterion for local recurrence was discrete mass, and size,shape, margin, echogenicity, and homogeneity were also analysed. Forty-one patients underwent surgery. RESULTS: Among 113 cases, 41 local recurrences were proven by surgery and histological analysis; well-defined, ovoid,homogeneous hypoechoic masses of various sizes were apparent. Sonographic sensitivity and specificity were both97%. MR sensitivity and specificity were 83% and 100% respectively, but in most cases in which MR had been usedthe masses were greater than 3cm in diameter. Two cases were false positive; these were thought to be granulomas,but were shown during follow-up lasting 36 and 14 months, respectively, to be unchanged hypoechoic nodules. Onecase was false negative. CONCLUSION: For the diagnosis of local recurrent soft tissue tumors, ultrasonography isvery useful. For early detcction, it is superior to MR imaging.

Ossified Soft Tissue Recurrence of Giant Cell Tumor: Three Case Report

We report three cases of recurrence of giant cell tumor characterized by ossification of surrounding soft tissue. On resection, the ossified rim in the soft tissue masses were pathognomonic of recurrence of giant cell tumor. Knowledge of this findings would help for accurate diagnosis and appropriate treatment.

Musculoskeletal Adipose tumors of the extremities: Benign vs Malignancy in MR Imaging

PURPOSE: The purpose of this study was to evaluate the MR findings of benign and malignant musculoskeletal adipose tumors and to determine the points of difference between these two types. MATERIALS AND METHODS: This study involved 41 histopathologically proven cases; 26 were benign lipoma and 15 were liposarcoma. T1- and T2-weighted images were obtained in all cases and enhancement study was performed in 15 case of benign lipoma and14 of liposarcoma. To determine MR findings and possible differences between the two groups, we retrospectively analyzed size, location, margin, degree of signal intensity, homogeneity, enhancement pattern and internal septa, as seen on MR images. RESULTS: On both T1- and T2-weighted images, all lipomas showed a signal intensity similar to that of subcutaneous fat. Twenty-one lipomas had thin and regular internal septa and three showed focal enhancement. On T1-weighted images, 13 of 15 liposarcomas showed linear strands or patchy or diffuse areas with high signal intensity, representing a fatty component. Ten liposarcomas showed inhomogeneous signal intensity and the other five, homogeneous intensity. Irregular and thick septa were seen in nine liposarcomas, and in 12 cases, nodular diffuse enhancement was documented. CONCLUSION: Homogeneity of signal intensity, enhancing pattern and internal septa might be useful MR findings for the differential diagnosis of benign lipoma and liposarcoma.

MR Findings of Primary Scalp Mass

PURPOSE: To evaluate the diagnostic value of MRI, we compared MR images of primary scalp mass with pathological findings. MATERIAL & METHODS: Eight cases in seven patients who had presented primary scalp mass during the previous three years were evaluated by MRI and confirmed with surgical excision and pathologic evaluation. 0.38T(Resonex 4000, USA) MRI was used and all MR images were analysed retrospectively. RESULTS: Eight pathologically confirmed cases consisted of three cases of epidermal cysts, one of steatocystoma simplex, three of neurofibromatosis and one of lymphangioma. All epidermal cysts were located in the occipital area and showed ahigher signal intensity than CSF in T1WI, and proton density and variable signal intensity in T2WI. The Steatocystoma showed a signal iniensity similar to fat in T1WI and proton density and a lower signal intensity than fat in T2WI. Neurofibromatosis accounted for three cases in two neurofibromatosis patients ; one was locatedin the right parieto-occipital area and accompanied by hematoma and skull defect ; two cases were located in the occipital and posterior cervical area of the same patient. The masses showed a higher signal intensity than musclein T1WI and hyper or iso intensity in T2WI with well enhancement. The lymphangioma showed a signal intensity similar to CSF in all pulse sequences and contained a fat component. CONCLUSION: MRI is a useful modality for evaluating primary scalp mass.

Radiological Findings of Primary Abdominal Malignant Fibrous Histiocytoma: Emphasis on CT Findings

PURPOSE: To evaluate the radiological findings of abdominal malignant fibrous histiocytomas. MATERIALS AND METHODS: We retrospectively reviewed the radiological findings of 13 masses in seven patients including two patients with multiple masses. The masses were located at the mesentery and omentum in three patients and at theretroperitoneum in four. Gastrointestinal examination using barium was performed in four patients, ultrasonographyin five and computed tomography in all. RESULTS: The average diameter of masses was 7.8cm(range : 1-20cm); plain abdominal films revealed soft tissue masses in all patients. Three of four barium studies demonstrated only displacement of bowel loops and the other showed findings of submucosal tumor. Eight of 11 masses were detected on ultrasonography and all were round or lobulated and had well defined margins. Four of these masses were greater than 8cm in diameter and showed homogeneous echogenicity with central hypo or anechoic area ; the remaining wereless than 8cm and showed relatively homogeneous echogenicity. On computed tomography, all 13 masses were seen as highly enhanced and well circumscribed. Seven were greater than 5cm in diameter and had internal low-densityareas. Peritumoral vessel-like structures were seen in eight masses and on plain abdominal radiograph and computed tomogram, calcification was seen in one patient. In no patient was combined retroperitoneal or intraperitoneal lymphadenopathy noted. CONCLUSION: Abdominal malignant fibrous histiocytomas are well-circumscribed, round orlobulated bulky masses with frequent necrosis and occasional calcification. Characteristically, there is nocombined lymphadenopathy and multiple masses are a rare manifestation. These findings may be helpful in the diagnosis of malignant fibrous histiocytoma.

Extra-Articular Synovial Chondromatosis: A case Report

A 60-year-old female presented with a slowly growing, painful mass in the superolateral portion of the rightt high. Physical examination, roentgenography, bone scan and magnetic resonance imaging revealed a soft tissue masswith mineralization which did not involve bone or joint. A triangular-shaped, mineralized lesion was found in the superior side of the greater trochanter on simple radiograph and on magnetic resonance imaging. It had not been detected clinically, and was asymptomatic. The masses were removed en bloc and diagnosed as extra articular osteochondroma. Eight months postoperatively, pain had almost been relieved.