Primary leiomyosarcoma of bone

We report a case of primary leiomyosarcoma in the right femoral diaphysis. Conventional radiographs revealed an indistinct osteolytic lesion with a very subtle periosteal reaction. MR imaging revealed an intramedullary lesion with a well-defined margin, cortical breakthrough and soft tissue extension. The lesion was isointense relative to muscle on T1-weighted imaging, iso-hypointense relative to fat on fast spin echo T2-weighted imaging, and hyperintense to muscle on fast spin echo T2-weighted imaging with fat saturation. A peripheral rim and intratumoral spoke-wheel-like enhancement in the soft tissue component of the tumor was noted on gadolinium-enhanced T1-weighted imaging with fat saturation. Such an enhancing pattern, which has not been described in the literature previously but has been seen in leiomyosarcomas elsewhere by both MR imaging and computed tomography, deserves further pathological correlation.     

Desmoid-type fibromatosis in the head and neck: CT and MR imaging characteristics

Introduction

In the head and neck region, desmoid-type fibromatosis is an uncommon tumor, and the imaging features have not been well described. The purpose of this study was to describe imaging features with their pathologic correlation of desmoid-type fibromatosis in this region.

Methods

Computed tomographic (CT) and magnetic resonance (MR) images of nine consecutive patients (five women and four men; age range, 2–72 years; mean age, 28 years) with desmoid-type fibromatosis in the head and neck were retrospectively evaluated, focusing on lesion location, size, shape, presence of a rim of surrounding fat, CT attenuation, signal intensity, and enhancement characteristics on MR with pathologic correlation.

Results

Desmoid-type fibromatosis involved perivertebral space (n?=?5) and carotid space (n?=?1) in six adult patients. In three pediatric patients, the fibromatosis primarily involved submandibular space (n?=?2) and masticator space (n?=?1) with frequent invasion to the adjacent spaces (3/3). A mean greatest dimension of 5.8 cm, elongated shape (7/9), and rim of surrounding fat (8/9) were the common features of the desmoid-type fibromatosis. Tumors often showed iso (3/7) or high attenuation (3/7) on postcontrast CT, high signal intensity (6/9) on T2-weighted image, iso signal intensity (8/9) on T1-weighted image, and strong MR enhancement (8/9). Characteristic nonenhancing low signal intensity bands (8/9) on all MR sequences were well correlated with dense collagenous stroma.

Conclusions

Desmoid-type fibromatosis in the head and neck of adults frequently involves perivertebral space. Along with various common imaging features, desmoid-type fibromatosis shows characteristic nonenhancing low signal intensity bands on MR images.     

Desmoid-type fibromatosis of the lower extremity: A unique case of complete lesion resolution following core needle biopsy

Desmoid-type fibromatosis (DF) is a rare neoplasm characterized by fibroblastic and myofibroblastic proliferation. While characterized as a benign lesion that does not metastasize, desmoid-type fibromatosis exhibits a wide range of behavior from aggressive local tissue invasion and post-surgical recurrence to spontaneous regression. Tumor regression can occur following systemic medical therapy or rarely may occur in the absence of therapy. We present a case of a 50-year-old female with a left thigh vastus medialis intramuscular mass which underwent imaging work-up and subsequent core needle ultrasound-guided biopsy showing results of desmoid-type fibromatosis. Following biopsy, the tumor showed prompt, complete regression with complete MRI resolution 2 months following biopsy. The patient showed no evidence of disease recurrence out to one year on MRI surveillance. This case report will discuss desmoid-type fibromatosis imaging features, treatment strategies, spectrum of disease behavior, and atypical behavior such as the spontaneous tumor regression as seen in this case report. To our knowledge there have been no reported cases of DF spontaneous regression 2 months following a core needle biopsy. Understanding the variable behavior of desmoid-type fibromatosis can assist the radiologist in guiding management of these lesions with the goal of optimizing clinical outcomes and preventing unnecessary aggressive treatments for stable or regressing disease.     

MR imaging features of solid pseudopapillary tumor of the pancreas in adult and pediatric patients

OBJECTIVE: This study was conducted to describe the MR imaging features of solid pseudopapillary tumor of the pancreas. CONCLUSION: Solid pseudopapillary tumor of the pancreas, a tumor typically seen in young women, is a large, well-defined, encapsulated lesion with heterogeneous high or low signal intensity on T1-weighted, heterogeneous high signal intensity on T2-weighted, and early peripheral heterogeneous enhancement with progressive fill-in on gadolinium-enhanced dynamic MR imaging. These features help differentiate this rare tumor from other pancreatic neoplasms.     

MRI and CT features of a malignant myoepithelioma of the scrotum: A case report and literature review

Malignant myoepithelioma of the scrotum is extremely rare. We report the case of a 51-year-old man with malignant myoepithelioma of the scrotum, wherein computed tomography and magnetic resonance imaging revealed a lobulated soft tissue mass with calcification, cystic component, and solid component with gradual contrast enhancement on dynamic contrast-enhanced scans. The patient presented with scrotal induration, and there was no elevation of tumor markers and no evidence of a metastatic lesion on computed tomography and magnetic resonance imaging. Histopathological examination of the resected scrotal specimen confirmed a well-circumscribed solid tumor with septa, a small area of hemorrhage, and necrosis. The subsequent diagnosis was malignant myoepithelioma of the scrotum. This case shows that scrotal malignant myoepithelioma might appear as a well-defined lobulated mass with cystic regions. We conjecture that the enhancement pattern and apparent diffusion coefficient values can be potential markers for scrotal myoepithelial tumors.     

Myxoid solitary fibrous tumor of the retroperitoneum: MRI findings with the pathologic correlation.

We report here on a case of solitary fibrous tumor of the retroperitoneum, and the tumor displayed a predominantly myxoid histology. A 56-year-old man presented with an incidentally detected retroperitoneal mass. On the MR images, the mass was observed as having iso-signal intensity on the T1-weighted images and high signal intensity on the fat-saturated T2-weighted images. The mass showed intense enhancement on the Gd-DTPA enhanced T1-weighted images. At surgery, a well-defined solid mass was found in the left retroperitoneum. The histological diagnosis was made as solitary fibrous tumor with a predominantly myxoid histology.     

Nerve sheath tumors: evaluation with CT and MR imaging.

Tumors of nerves are classified into benign (schwannoma and neurofibroma) and malignant nerve sheath tumors. Schwannomas almost always occur as solitary lesions, whereas neurofibromas may occur alone or in a greater number, especially in patients with the peripheral form of von Recklinghausen's disease. Benign nerve sheath tumors often present as asymptomatic, slowly growing soft tissue masses. Although malignant nerve sheath tumors are relatively rare, a sudden increase in the size of a lesion, in particular in a patient with neurofibromatosis, should raise the suspicion of malignant change. On computed tomography (CT) and magnetic resonance imaging (MR) a benign nerve sheath tumor usually appears as a well-defined, oval, spherical or fusiform mass with smooth borders and distinct outlines, located in the subcutaneous tissue or centered at the expected anatomic location of a nerve, with displacement of adjacent soft tissues. Generally nerve sheath tumors have a low density on unenhanced CT scans. On MR they are isointense to muscle on T1-weighted images, whereas on T2-weighted images the signal intensity is high. Both on CT and MR the degree of contrast enhancement is moderate to marked and may be homogeneous or inhomogeneous. MR has become the method of choice for evaluating the anatomic location, contour, and relation of a nerve sheath tumor to adjacent neural, vascular, and muscular structures. The imaging criteria for malignant nerve sheath tumors are not specific enough to distinguish them from other malignant soft tissue tumors, so that neither CT nor MR can establish a definite diagnosis.     

Neurothekeoma in the upper extremity: magnetic resonance imaging and computed tomography findings

Neurothekeomas are rare benign tumors of soft tissue that are of presumed neural sheath origin. This report describes the magnetic resonance imaging and computed tomography features of a neurothekeoma in the left forearm of a 38-year-old woman with a 2-year history of a painful mass. Magnetic resonance imaging showed a smooth-bordered ovoid lesion within the inner portion of the extensor digitorum muscle with a Hounsfield number of 15. The lesion had intermediate signal on T1-weighted images, high signal on T2-weighted images, and mild to moderate heterogeneous gadolinium contrast enhancement.     

Giant cell tumors of the tendon sheath may present radiologically as intrinsic osseous lesions

The purpose of this study was to explain radiographic features of giant cell tumors of the tendon sheath (GCTTS), in particular, osseous extension, by correlating imaging findings with histology in order to increase the accuracy of radiological diagnosis. In a series of 200 consecutive osseous (pseudo) tumors of the hand, on radiography, six patients presented with an intrinsic osseous lesion caused by a histologically confirmed neighboring GCTTS. Available radiographs, computed tomography (CT), and contrast-enhanced magnetic resonance (MR) images were correlated with histology. Radiography showed osseous lesions consisting of well-defined cortical defects in four (one of whom also demonstrated cortical scalloping) and a slightly expansile, well-defined osteolytic lesion in two patients. MR obtained in four patients showed the extraosseous tumor invading/eroding bone and causing cortical scalloping (three and one patients, respectively). Extension depicted on MR was confirmed on the two available resection specimens. All lesions were polylobular (cauliflower or mushroom like) and neighbored tendon sheaths. Dense collagen and hemosiderin-loaded macrophages explained the high CT attenuation and the low MR signal intensity on T2-weighted images that was observed in all four MR and in all two CT scans. The high density of proliferative capillaries explained the marked enhancement observed in all four patients with gadolinium (Gd)-chelate-enhanced MR imaging. GCTTS is a soft tissue (pseudo) tumor that may invade bone and as a consequence mimick an intrinsic osseous lesion on radiographs. In such cases, specific MR and CT features that can be explained by histological findings can be used to suggest the correct diagnosis.     

Computed tomography and magnetic resonance imaging findings of soft tissue perineurioma

Soft tissue perineurioma is an uncommon benign peripheral nerve sheath tumor, although it is the most common subtype of perineuriomas. We present a case of soft tissue perineurioma in the left groin of a 48-year-old man. Precontrast computed tomography showed a homogeneous hypodense mass that showed faint enhancement. The mass appeared with hypointensity on T1-weighted magnetic resonance (MR) images and heterogeneous hyperintensity on T2-weighted MR images. Slight contrast uptake was noted on enhanced T1-weighted MR images with fat suppression. Although these CT and MR imaging findings were nonspecific, the overall imaging features are similar to those of schwannomas.     

Imaging of musculoskeletal fibromatosis.

The musculoskeletal fibromatoses comprise a wide range of lesions with a common histopathologic appearance. They can be divided into two major groups: superficial and deep. The superficial fibromatoses are typically small, slow-growing lesions and include palmar fibromatosis, plantar fibromatosis, juvenile aponeurotic fibroma, and infantile digital fibroma. The deep fibromatoses are commonly large, may grow rapidly, and are more aggressive. They include infantile myofibromatosis, fibromatosis colli, extraabdominal desmoid tumor, and aggressive infantile fibromatosis. Radiographs typically reveal a nonspecific soft-tissue mass, and calcification is common only in juvenile aponeurotic fibroma. Advanced imaging (ultrasonography, computed tomography, and magnetic resonance [MR] imaging) demonstrates lesion extent. Involvement of adjacent structures is common, reflecting the infiltrative growth pattern often seen in these lesions. MR imaging may show characteristic features of prominent low to intermediate signal intensity and bands of low signal intensity representing highly collagenized tissue. However, fibromatoses with less collagen and more cellularity may have nonspecific high signal intensity on T2-weighted images. Local recurrence is frequent after surgical resection due to the aggressive lesion growth. It is important for radiologists to recognize the imaging characteristics of musculoskeletal fibromatoses to help guide the often difficult and protracted therapy and management of these lesions.     

CT and MRI features of low-grade fibromyxoid sarcoma in the shoulder of a pediatric patient

We report the computed tomography (CT) and magnetic resonance imaging (MRI) features of a 10-year-old boy with low-grade fibromyxoid sarcoma (LGFMS) in the shoulder and correlate them with the clinicopathological features. LGFMS, a rare soft tissue sarcoma with bland histological features and paradoxically aggressive behavior, tends to occur in superficial regions and in children more than previously recognized. To date, few imaging studies have been reported, particularly in pediatric patients. In this case, precontrast CT showed a low- to isodensity mass and punctate calcification. On contrast-enhanced CT, heterogeneous enhancement was seen. MRI findings correlated well with the pathological features of the tumor. The myxoid area showed high signal intensity on T2-weighted MR images and heterogeneous enhancement after administration of contrast material; the hypercellular area demonstrated lower signal intensity on T2-weighted MR images and slight enhancement.     

CT and MRI findings of carcinoma showing thymus-like differentiation

Carcinoma showing thymus-like differentiation (CASTLE) is a rare tumor that occurs in the soft tissue of the neck or in the thyroid gland. We report a case of CASTLE in a 54-year-old man presenting with hoarseness. Computed tomography (CT) and magnetic resonance imaging (MRI) showed a mass enclosing the right carotid artery with the shape of lobulation and invasion to the trachea. The mass was hypointense on T1-weighted imaging and, on T2-weighted imaging, showed a hyperintense periphery with isointense center relative to muscle. In dynamic MRI, the mass revealed gradual but slight heterogeneous enhancement from the periphery. Diagnosis was confirmed by histopathology.     

Infantile desmoid-type fibromatosis with involvement of temporal bone: case report

Infantile desmoid-type fibromatosis is a rare, benign, infiltratively growing tumor of the soft tissue. The histological classification is often confusing due to various patterns. Although surgical excision is the treatment of choice, local recurrence is high. Ultrasound, CT, and MRI cannot differentiate the different types of fibrous lesions, but are very essential, showing the localization and infiltrated tissues. We report an unusual case of desmoid-type fibromatosis destroying the temporal bone in a now-5-year-old boy. The literature contains only few reports of radiolological findings in patients with infantile fibromatosis. Correspondence to: T. Hagen     

CT and MR findings of basal cell adenoma of the parotid gland

We report a case of basal cell adenoma in the left parotid gland. A 34-year-old woman presented with a non-tender mass in the left parotid gland. She had first noted it 7- years previously, and it had been gradually increasing in size. The tumor was well-circumscribed with a smooth contour. On noncontrast-enhanced CT, the tumor showed homogeneous soft tissue attenuation. No cystic portion or calcification was seen. The tumor showed homogeneous moderate enhancement on contrast-enhanced CT. Capsule-like ring enhancement was demonstrated. On T1-weighted MR imaging, the tumor was homogeneously hypointense to the surrounding parotid tissue and isointense to muscle. On T2-weighted imaging the tumor was homogeneously hyperintense to muscle but slightly hypointense to the surrounding parotid tissue. On Gd-enhanced T1-weighted imaging, the tumor demonstrated homogeneous moderate enhancement. Capsule-like ring enhancement was also demonstrated. Salivary (technetium-99m-pertechnetate) scintigraphy did not show any uptake in the tumor.     

Preoperative CT and MR imaging of inferior vena cava leiomyosarcoma

We investigated the radiological findings of five patients with primary leiomyosarcoma of the inferior vena cava (IVC) comparing cavography, computed tomography (CT), and magnetic resonance imaging (MRI). The radiographic presentation ranged from an intraluminal lesion with obstruction of the IVC to a tumor mass extending from the media musculature into the surrounding perivascular tissue with only slight protrusion into the lumen. The lesions were associated with late or few symptoms. Pathognomonic radiological findings could not be established. In cases with an extraluminal growth a lobulated, well-defined, encapsulated tumor with an inhomogeneous contrast uptake is characteristic in CT studies. Additional information was provided by MRI. Leiomyosarcomas with extraluminal involvement showed homogeneous intermediate signal intensity (SI) on Tl-, and mixed intermediate/high SI on T2-weighted images. In cases with predominantly intraluminal growth, both CT and MRI demonstrated the IVC to be dilatated and allowed to differentiate between tumor extent and obliterating thrombosis. Modern imaging modalities allow an early and accurate pre-operative diagnosis resulting in a higher rate of surgical resection and improvement of survival.     

Magnetic resonance imaging of musculoaponeurotic fibromatosis

Musculoaponeurotic fibromatosis can be mistaken for soft-tissue sarcoma both clinically and on X-ray computed tomography. Magnetic resonance imaging (MRI) in three patients with this condition enabled the correct diagnosis to be made prospectively in two. The appearance on MRI of a heterogeneous mass with well-defined, predominantly peripheral areas of very low signal intensity due to dense fibrous tissue and areas of medium to high signal intensity corresponding to a more cellular stroma should raise the the suspicion of musculoaponeurotic fibromatosis. Cellular areas within the tumour showed moderate enhancement after gadolinium diethylene triamine pentaacetic acid administration.     

Leiomyosarcoma of the vagina: MR findings

We report the magnetic resonance imaging findings of a case of vaginal leiomyosarcoma. The lesion was demonstrated as a well-defined heterogeneously hyperintense mass within the vagina on T2-weighted images and was demonstrated as a hypointense mass on T1-weighted images. The mass showed irregular enhancement on fat-suppressed T1-weighted images after administration of gadopentate dimeglumine. On pathological specimen, the nonenhancing foci of the mass were seen as the necrotic portion of the lesion.     

Soft tissue perineurioma of the foot with 10q24 rearrangements: unique MRI features with histopathologic correlation

Perineurioma is an uncommon benign peripheral nerve sheath tumor with advanced perineurial differentiation. Two distinct subtypes are recognized: intraneural and soft tissue. We herein present a unique case of soft tissue perineurioma in the right foot of a 43-year-old man. Radiographs showed a non-specific soft tissue mass. On computed tomography scan, the mass was iso- to slightly hypodense relative to muscle. On T1- and T2-weighted images, the mass exhibited iso- to slightly low signal intensity relative to muscle with foci of high signal intensity. Slight contrast enhancement was noted on enhanced T1-weighted images with fat suppression. A marginal excision of the tumor was performed and histopathologic examination confirmed the diagnosis of soft tissue perineurioma. The clinicopathologic, radiologic, and cytogenetic findings are described, and the relevant literature is reviewed.     

Imaging of intra- and extraabdominal desmoid tumors.

Desmoid tumors are characterized by proliferation of fibroblastic cells that arise from the fascia or aponeurosis of muscle. They are most commonly found in the abdomen of adults, arising from the anterior abdominal wall, mesentery, or retroperitoneum. At sonography, desmoids have variable echogenicity, with smooth, well-defined margins. On contrast-enhanced computed tomographic scans, the tumors are generally high attenuation (relative to muscle) and have either ill- or well-defined margins. At magnetic resonance imaging, desmoids have low signal intensity relative to muscle on T1-weighted images and variable signal intensity on T2-weighted images. There are no specific imaging features to distinguish desmoid tumors from other solid masses. The diagnosis of desmoid tumor should be considered in patients with an abdominal mass, a history of abdominal surgery or injury, or Gardner syndrome.