Soft Tissue Tumors - PDF

Soft tissue tumours and tumour like Lesions: A Systematic Imaging Approach Maria Tsitskari MD,EBIR Consultant of Vascular and Interventional Radiology Apollonio Private Hospital Soft tissue tutors and tumorlike Lesions: A Systematic Imaging Approach Patients are commonly referred for imaging to eval...

Soft tissue tumours and tumour like Lesions: A Systematic Imaging Approach Maria Tsitskari MD,EBIR Consultant of Vascular and Interventional Radiology Apollonio Private Hospital Soft tissue tutors and tumorlike Lesions: A Systematic Imaging Approach Patients are commonly referred for imaging to evaluate a soft-tissue mass in the trunk or extremities These lesions range from nonneoplastic conditions to benign and malignant tumors Imaging provides a limited ability to reliably distinguish between benign and malignant soft-tissue lesions Primary goal for the imaging referral is to confirm the presence of a mass and to assess its extent in preparation for possible treatment Clinical history, lesion location, mineralization on radiographs, and signal intensity (SI) characteristics on magnetic resonance (MR) images can help to narrow the Ddg Soft tissue tutors and tumorlike Lesions: A Systematic Imaging Approach Soft-tissue tumors are histologically classified on the basis of the soft-tissue component that comprises the lesion, but this does not imply that the tumor arises from that tissue WHO classification Soft tissue tutors and tumorlike Lesions: A WHO classificationSystematic Imaging Approach Soft tissue tutors and tumorlike Lesions: A Systematic Imaging Approach WHO classification Soft tissue tutors and tumorlike Lesions: A Systematic Imaging Approach Clinical History and Physical Examination age, recent trauma, fluctuating mass size, history of malignant cancer and familial syndromes, and physical examination can help with lesion characterisation e.g - liposarcoma is a common malignant soft-tissue mass in adults, it is rare in early childhood - a history of trauma can support the diagnosis of a hematoma or myositis ossificans; - rapid growth is certainly a concern for malignancy, a benign mass may grow rapidly owing to haemorrhage - fluctuation in lesion size can be seen with ganglia or hemangiomas - multiple lesions consider metastatic disease and certain syndromes, including type 1 neurofibromatosis and hereditary multiple lipomas - at physical examination, if the mass is mobile or fixed can be helpful Location Soft tissue tutors and tumorlike Lesions: A Systematic Imaging Approach Certain masses occur in specific locations in the body, aiding in lesion characterisation - elastofibroma is a benign fibroelastic tumor that occurs almost exclusively along the inferomedial border of the scapula, deep to the latissimus dorsi and rhomboid major muscles - a teardrop-shaped mass found along the plantar aspect of the second or third interspace of the foot in the region of the plantar digital nerve, with appropriate SI characteristics, has a high likelihood of being a Morton neuroma Soft tissue tutors and tumorlike Lesions: A Systematic Imaging Approach Location Soft tissue tutors and tumorlike Lesions: A Systematic Imaging Approach Location Recognizing that a lesion arises from a specific structure (eg, nerves, vessels, or tendons) can help in lesion characterization. i) tumors arising from nerves are typically benign PNSTs, which include schwannomas and neurofibromas ii) fat-containing tumors can also arise from nerve- lipomatosis of a nerve iii) vascular neoplasms typically have dilated tortuous vessels entering and/or exiting the lesion and include hemangiomas, lymphangiomas, and angiosarcomas iv) lesions arising from tendons are most commonly GCTs of the tendon sheath , however, ganglia, lipomas, and fibromas are all masses that may arise from a tendon sheath. Soft tissue tutors and tumorlike Lesions: A Systematic Imaging Approach Location the utility of radiographs in evaluating soft-tissue lesions is limited Radiographs should be assessed for - distortion of tissue planes - radiolucent fatty areas - indolent or aggressive remodeling of the bone - radiolucent foreign bodies - soft-tissue calcifications or ossification e.g If there is a clustered group of phleboliths, one should consider the presence of a softtissue hemangioma Soft tissue tutors and tumorlike Lesions: A Systematic Imaging Approach Radiographs the utility of radiographs in evaluating soft-tissue lesions is limited Radiographs should be assessed for - distortion of tissue planes - radiolucent fatty areas - indolent or aggressive remodeling of the bone - radiolucent foreign bodies - soft-tissue calcifications or ossification e.g If there is a clustered group of phleboliths, one should consider the presence of a softtissue hemangioma Soft tissue tutors and tumorlike Lesions: A Systematic Imaging Approach Radiographs lipoma synovial sarcoma in the forefoot. (a) Anteroposterior radiograph shows irregular soft-tissue calcifications (arrows) surrounding third metatarsal shaft. (b) Coronal contrast-enhanced fat-suppressed T1-weighted SPGR MR image shows a heterogeneous enhancing mass (arrows) between the third and fourth metatarsal shafts Soft tissue tutors and tumorlike Lesions: A Systematic Imaging Approach Technical Considerations for MR Imaging of Soft-Tissue Masses MR imaging is well-suited for the evaluation of soft-tissue tumors and tumorlike lesions because of its intrinsically high soft-tissue contrast and its capability to aid in imaging superficial and deep soft tissues over both large and small fields of view T1- and T2-weighted sequences a fat-suppressed T1-weighted sequence - -asses that contain fat will lose SI on fat a fat-suppressedT2-weighted sequence - to highlight areas of increased edema both within and around the mass T2*-weighted gradient-echo sequence is a useful adjunct sequence for assessing the presence of hemosiderin intravenous contrast agent is used to distinguish cystic from solid structures, to demonstrate the relative vascularity of the masses, and, occasionally, to help highlight tissue planes to aid in assessing the degree of invasion of a mass into vessels and other structures Soft tissue tutors and tumorlike Lesions: A Systematic Imaging Approach Technical Considerations for MR Imaging of Soft-Tissue Masses Sagittal T2-weighted fast SE MR images in 45-year-old woman show posterior chest desmoid tumor. (a) MR image without fat suppression shows mass (arrows) in subcutaneous soft tissues that is only slightly hyperintense to muscle. (b) Fat-suppressed MR image shows same mass (arrows) as much more hyperintense than muscle owing to changes in dynamic range. Soft tissue tutors and tumorlike Lesions: A Systematic Imaging Approach Soft tissue tutors and tumorlike Lesions: A Systematic Imaging Approach If the mass has areas of hyperintense T1 signal, the next step is to evaluate suppression on fat-suppressed T1-weighted images. If the hyperintense area is suppressed, then the lesion contains fat, and the most likely diagnoses include lipoma, lipoma variant, well-differentiated liposarcoma, hemangioma, and mature ossification If the lesion does not lose SI on the fat-suppressed T1-weighted MR images, then it is composed of another substance that causes T1 shortening, such as methemoglobin, proteinaceous fluid, or melanin. A history of trauma may account for a hematoma with methemoglobin. Ganglia, abscesses, and epidermoid inclusion cysts with high protein content may be hyper intense If the patient has a history of melanoma and a mass with high T1 SI, the possibility of a melanoma metastasis should be considered Soft tissue tutors and tumorlike Lesions: A Systematic Imaging Approach melanoma metastasis (arrowhead) in anterior abdominal subcutaneous soft tissues. T1weighted (a) opposed phase and (b) fatsuppressed SPGR MR images show hyperintense lesion in subcutaneous fat. (c) Contrast-enhanced fat-suppressed T1-weighted SPGR MR image shows equivocal enhancement Soft tissue tutors and tumorlike Lesions: A Systematic Imaging Approach A mass that is lower in SI than skeletal muscle on T2-weighted MR images is considered to be hypointense Substances that appear hypointense on T2-weighted images include fibrosis, hemosiderin, and calcification Masses that are composed of fibrotic material represent a broad spectrum of benign and malignant lesions, ranging from fibrotic scars to fibromas and some fibrosarcomas Masses that contain large amounts of hemosiderin include pigmented villonodular synovitis, GCT of the tendon sheath, and a variety of hemorrhagic masses plantar fibroma Soft tissue tutors and tumorlike Lesions: A Systematic Imaging Approach GCT arising from flexor tendons to long, ring, and small fingers at level of the radiocarpal joint. (a) Axial T2weighted fast SE MR image shows lobulated hypointense mass (arrows) encasing several flexor tendons (arrowheads). (b) Coronal T2*-weighted gradient-echo MR image shows blooming artifact (arrowheads) that highlights areas of hemosiderin deposition in the tumor (arrows) Soft tissue tutors and tumorlike Lesions: A Systematic Imaging Approach Water and water-filled masses are T2 hyperintense due to the prolonged T2 relaxation time of water Some solid masses can also appear to be quite T2 hyperintense The differential diagnosis for lesions that are predominantly T2 hyperintense includes not only fluid-filled lesions (eg, ganglia, synovial cysts, and seromas) but also solid lesions (eg, myxomas, myxoid sarcomas, some PNSTs, and small synovial sarcomas) An intravenous gadolinium-based contrast agent is an important step to distinguish between true cysts and solid lesions Soft tissue tutors and tumorlike Lesions: A Systematic Imaging Approach a) Lipomas and Other Lipomatous Lesions Lipomas are the most common soft-tissue tumor and contain tissue histologically identical to adipose fat The incidence of lipomas is up to 2.1 per 100 individuals Lipomas are radiolucent on radiographs and computed tomographic (CT) images and are isointense relative to subcutaneous fat on MR images obtained with all pulse sequences The classic lipoma is composed entirely of fat, without areas of nodularity or thickened septations Soft tissue tutors and tumorlike Lesions: A Systematic Imaging Approach a) Lipomas and Other Lipomatous Lesions a) Spin-echo (SE) T1-weighted MR image shows uniformly hyperintense lesion with SI identical to that of subcutaneous fat. (b) Fat-suppressed spoiled gradient-recalled acquisition in the steady state (SPGR) T1-weighted MR image shows uniform fat suppression of lesion and no thickened septae or nodular areas. Soft tissue tutors and tumorlike Lesions: A Systematic Imaging Approach a) Lipomas and Other Lipomatous Lesions The important differential diagnosis for a benign lipoma includes a well-differentiated liposarcoma, which may also demonstrate a large fat component. Other subtypes of liposarcoma (dedifferentiated, myxoid, and pleomorphic) may contain minimal or no visible fat Features found to favor a diagnosis of well-differentiated liposarcoma include lesion size greater than 10 cm, presence of thick (>2-mm) septae (diffuse or focal), presence of globular and/or nodular nonadipose areas or masses, and lesion composition of less than 75% fat Soft tissue tutors and tumorlike Lesions: A Systematic Imaging Approach b) Hemangiomas Hemangiomas are benign vascular lesions composed of various vessels They are common tumors in infancy and childhood but can occur in any age group Clinically can manifest with bluish skin discoloration and a history of size fluctuation Occasionally, pain may occur following exercise owing to shunting of blood flow away from the surrounding tissue into the hemangioma On images, hemangiomas can contain serpentine vessels, fat, smooth muscle, hemosiderin, and phleboliths Identifying phleboliths (focal dystrophic mineralizations in a thrombus) on radiographs or CT images can be helpful in characterisation Changes in the bone, including periosteal reaction, cortical and medullary changes, and overgrowth, can be seen On MR images, hemangiomas may be well-circumscribed or have poorly defined margins, with varying amounts of hyperintense T1 signal owing to either reactive fat overgrowth or hemorrhage Areas of slow flow typically have high T2 SI, while rapid flow can demonstrate a signal void on images obtained with a non–flow-sensitive sequence Soft tissue tutors and tumorlike Lesions: A Systematic Imaging Approach b) Hemangiomas (a) Axial SE T1-weighted MR image shows heterogeneous mass (arrows) with focal area of T1 hyperintensity (arrowhead). (b) Coronal contrast agent–enhanced fat-suppressed SPGR T1-weighted MR image shows heterogeneous enhancement (arrow) with large entering vessels (arrowheads). Soft tissue tutors and tumorlike Lesions: A Systematic Imaging Approach b) Hemangiomas Soft tissue tutors and tumorlike Lesions: A Systematic Imaging Approach C) Ganglia Ganglia commonly occur in the hand, wrist, and feet and can arise from joint capsules, bursae, ligaments, tendons, and subchondral bone Clinically, ganglia are usually asymptomatic; however, symptoms can develop from mass effect, including nerve compression, on adjacent tissue The lesions can also fluctuate in size Typically there are no findings on radiographs, but they but may show nonaggressive remodeling of the bone On MR images, the lesions typically appear as round or ovoid masses that are uni- or multiloculated, with smooth or slightly lobulated surfaces, and are in close proximity to a joint or tendon Ganglia are usually isointense or slightly hypointense to muscle on T1-weighted MR images and hyperintense on T2-weighted MR images and have a thin rim of contrast enhancement, with or without thin low-SI enhancing septae Soft tissue tutors and tumorlike Lesions: A Systematic Imaging Approach C) Ganglia (a) Fat-suppressed fast SE T2-weighted MR image shows cystlike hyperintense lesion. (b) Contrast-enhanced fat-suppressed T1weighted MR image shows rim enhancement without internal or nodular enhancement Soft tissue tutors and tumorlike Lesions: A Systematic Imaging Approach d) Peripheral Nerve Sheath Tumors PNSTs can be benign and malignant Benign PNSTs include both schwannomas (neurilemomas) and neurofibromas (10% of benign soft-tissue tumors) PNSTs can manifest with both motor and sensory nerve disturbances May appear as a well-defined smooth-bordered fusiform mass that is aligned along the nerve The “split fat sign” can be associated with PNSTs: As the tumor enlarges, a surrounding rim of normal fat is maintained Benign PNSTs are typically isointense to muscle on T1-weighted MR images and slightly hyperintense to fat on T2-weighted MR images On cross-sectional MR images, a “target sign” appearance may be seen on T2-weighted images in some benign PNSTs, more commonly in neurofibromas than schwannomas Contrast enhancement in benign PNSTs is variable Malignant PNSTs account for 6% of soft-tissue sarcomas and are associated with type 1 neurofibromatosis in 50% of cases Malignant PNSTs can be difficult to differentiate from benign PNSTs; however, malignant PNSTs are typically larger and have ill-defined margins, rapid growth, and central necrosis Soft tissue tutors and tumor-like lesions: A Systematic Imaging Approach d) Peripheral Nerve Sheath Tumors Coronal fast SE T2-weighted MR image of wrist ulnar nerve (arrows) entering and exiting a hyperintense schwannoma (arrowhead) slightly eccentrically to the mass. Axial fat-suppressed fast SE T2-weighted MR image schwannoma arising from radial nerve in upper arm. Lesion has a target appearance, with central hypointensity (arrow) and peripheral hyperintensity (arrowhead). Soft tissue tutors and tumor-like lesions: A Systematic Imaging Approach e) Myositis Ossificans Myositis ossificans is a benign ossifying soft-tissue mass that occurs in muscle MC of extremities Lesions are suspected to arise following trauma; May be asymptomatic or may present with pain, swelling, and, occasionally, an elevated erythrocyte sedimentation rate The appearance of myositis ossificans on images varies, depending on its stage of development. Calcification is rarely seen on radiographs in the first few weeks but can become apparent 3–8 weeks after onset, starting peripherally and progressing centrally in a zonal pattern The MR appearance also varies - early lesions are poorly defined and isointense on T1-weighted images, heterogeneously T2 hyperintense, and have diffuse surrounding soft-tissue edema - on both T1- and T2-weighted images, mature lesions are well-defined masses that are isointense to fat centrally and have low SI peripherally, without surrounding soft-tissue edema - early-stage myositis ossificans can enhance (39) and can be mistaken for sarcoma. Soft tissue tutors and tumor-like lesions: A Systematic Imaging Approach e) Myositis Ossificans myositis ossificans in right groin. (a) Anteroposterior radiograph shows mass (arrow) with peripheral mineralization. (b) Axial contrast-enhanced fat-suppressed T1-weighted SPGR MR image shows central and perilesional enhancement (arrow). Soft tissue tutors and tumor-like lesions: A Systematic Imaging Approach e) Morton Neuromas Coronal SE T1-weighted MR image in 37-year-old woman with forefoot pain shows teardrop-shaped hypointense lesion (arrow) in third interspace; location is typical for a Morton neuroma.