Pediatric Orbit Tumors and TumorlikeLesions: Nonosseous Lesions of the

Extraocular Orbit

Dr Sidra AfzalNew Radiology dept.

SHL Lahore

•Nonosseous, extraocular orbital tumors in children most commonly manifest with the clinical finding of proptosis.

•The treatment and prognosis of orbital lesions are widely varied, and imaging studies may help in their diagnosis and management.

•In this presentation, the clinical and imaging features of these lesions are described and correlated, and the differential diagnoses are reviewed.

Rhabdomyosarcoma

• Rhabdomyosarcoma is the most common mesenchymal tumor in children, accounting for about 5% of all childhood cancers and the most prevalent extraocular orbital malignancy in children.

Clinical features

• mean patient age of 6–8 years • The less common alveolar form generally affects

older children or adolescents• It is aggressive, rapidly growing tumor and most

often manifests with rapidly progressive proptosis or globe displacement.

• Other common signs and symptoms include conjunctival and palpebral swelling, which may suggest the clinical diagnosis of orbital cellulitis

• There is a slight male predilection, with a male-to-female ratio of 5:3

Imaging Features• Reports describing the ultrasonographic (US) and Doppler US

appearances of orbital rhabdomyosarcoma are limited, because US findings are nonspecific and US is insensitive for depicting intracranial spread

• CT and MR imaging play important roles in the preoperative evaluation, staging, and follow-up of orbital rhabdomyosarcomas

• CT is particularly suited for showing bone involvement, and MR imaging is sensitive for depicting intracranial extension

Sagittal T1-weighted magnetic resonance (MR) image shows a well-circumscribed extraconal mass (arrowhead) superior to the ocular globe and isointense relative to muscle. Another sagittal MR image shows that the mass is separate from the superior rectus muscle (arrow)

On the axial T2-weighted image, the mass is heterogeneous in signal intensity and predominantly hyperintense relative to gray matter and muscle. Coronal T1-weighted image obtained after intravenous administration of gadolinium-based contrast material reveals intense enhancement of the tumor

Rhabdomyosarcoma involving the orbit and maxillary sinus in an 18-year-old girl witherythema of the right lower eyelid followed by proptosis 2 months later (a) Unenhanced coronal computed tomographic (CT) image (soft-tissue window) demonstrates a large, irregular soft-tissue mass in the maxillary sinus and inferior orbit that is iso- to slightly hyperattenuating relative to muscle. There is marked destruction of the bony orbital floor (arrowhead). (b) Same image, shown with a bone window level, better depicts the bone destruction (arrowhead).

Embryonal rhabdomyosarcoma in a 4-year-old girl with right proptosis. (a) Axial T1-weighted MR image demonstrates a well-defined mass that is iso- to slightly hypointense relative to muscle (arrowhead). Note the swelling of the upper eyelid. (b) Axial T1-weighted image with fat saturation shows intense, rimlike enhancement (arrowhead) of the mass and overlying lid.

Differential diagnosis• Subperiosteal hemorrhage caused by trauma may mimic the

appearance of rhabdomyosarcoma, especially on CT scans, since it causes erosive changes in bone as it resolves. MR imaging may be helpful in demonstrating the changing signal intensity of evolving blood products, which are infrequently found within rhabdomyosarcoma.

• Orbital cellulitis with abscess , similar to rhabdomyosarcoma, commonly manifests with rapid onset of eyelid swelling and proptosis. Both conditions may also show imaging findings of an orbital mass and adjacent paranasal sinus involvement. Contrast-enhanced MR images can be helpful for distinguishing sinus secretions from enhancing tumor that involves the paranasal sinus.

Dd • Dermoid cyst is the most common orbital mass in children, and it

may clinically and radiologically mimic rhabdomyosarcoma if it is complicated by rupture, which causes an intense inflammatory response in the surrounding tissues.

• Imaging features that suggest a dermoid include a cystic appearance, internal fat attenuation or signal intensity (T1 hyperintensity), and internal calcification, all of which are uncommon in rhabdomyosarcoma. Bone changes are seen with most dermoids, usually as an indolent appearing fossa near the zygomaticofrontal suture, rather than the permeative erosion seen in rhabdomyosarcoma with bone invasion. Also, fluid levels are common in dermoid cysts but rare in rhabdomyosarcoma

Dd

• Vasculogenic tumors may occur in the orbit in young children and may appear similar to rhabdomyosarcoma. The imaging features of capillary hemangiomas and venous-lymphatic malformations will be shortly discussed.

• Other differentials include LCH, LEUKEMIA, LYMPHOMA AN NEUROBLASTOMA METS.

Vasculogenic Lesions

• Vascular lesions account for 5%–20% of orbital masses and hemangioma and lymphangioma are the most common vascular lesions in the orbit

• Other vascular lesions are not neoplasms but rather developmental anomalies ,called vascular malformations.

Infantile hemangioma

• Infantile hemangioma is the most common tumor of infancy. Sixty percent of these tumors occur in the head and neck

• Hemangiomas represented 3% of all orbital lesions and 17% of vasculogenic lesions of the orbit.

Clinical features

• Hemangioma has no known familial or hereditary association. There is a slight female predilection, with a female-to-male ratio of 3:2 . The tumor may be present at birth as a reddish macule, but in most cases the tumor becomes apparent within the first few weeks to months of life.

• Almost all cases are diagnosed within the first 6 months of life. Hemangiomas then enter a proliferative phase, which lasts up to 10 months after diagnosis, followed by a short period of stabilization and then a prolonged period of slow involution, which may last as long as 7–10 years

Clinical features

• Some orbital hemangiomas may be associated with cerebral and vascular anomalies known as PHACES syndrome, which is an acronym encompassing posterior fossa anomalies ,hemangiomas of the face, arterial abnormalities (including coarctation of the aorta), cerebral vascular anomalies, eye abnormalities, and sternal or ventral developmental anomalies

Imaging Features• US performed by an experienced practitioner is

useful for evaluation of suspected vasculogenic lesions and for their follow-up.

• In the proliferative phase, the hemangioma is smoothly contoured and of variable echogenicity, usually hyperechoic.

• Doppler imaging demonstrates marked intralesional flow, high density of vessels (more than five vessels per square centimeter), increased arterial and venous flow velocity , and low resistance arterial flow. During the involutional phase, the size and number of vessels in the lesion decline

Imaging Features• CT is better suited than US for showing the full extent of

hemangiomas• On CT , In the proliferative phase, the mass is fairly

homogeneous and isoattenuated relative to muscle, although the attenuation may be higher than that of normal brain tissue due to blood in the vascular spaces.. After intravenous administration of contrast material, the tumor enhances promptly, markedly, uniformly,and persistently . The lesions are usually well demarcated but may have indistinct margins.

• During involution, the lesion is progressively replaced by fat, which is well demonstrated on CT scans. The mass becomes more heterogeneous and enhances less.

Imaging Features• MR imaging is particularly well suited to the characterization

of hemangiomas because of its superior tissue contrast and sensitivity to vascular flow. The well-defined marginated mass is typically iso- to hyperintense relative to muscle on T1-weighted images and moderately hyperintense on T2-weighted images, with flow voids at the periphery of or within the tumor

• In the involutional phase, the deposition of fat in the tumor confers increased signal intensity on both T1- and T2-weighted images. The fibrosis causes areas of decreased T2 signal.

• After intravenous administration of gadolinium-based contrast material, the mass generally enhances intensely and uniformly during the proliferative phase. Enlarged feeding arteries can be shown at MR angiography

Conventional angiography is now reserved for the few cases in which embolotherapy is contemplated for the treatment of threatening complications that are recalcitrant to medical therapy. MR angiograms show a well-defined, lobular, hypervascular mass with prolonged capillary stain and large feeding and draining vessels

Infantile hemangioma in a 2-month-old infant who was noted to have a mass in the left temporal area shortly after birth. (a) Coronal T2-weighted image shows a mass slightly hyperintense relative to muscle and brain that contains numerous black flow voids (arrowheads). (b) Axial T2-weighted image shows that the mass extendsinto the temporal region. Note the prominent intratumoral flow voids (arrowhead)

Capillary hemangioma in an 8-week-old girl with a 2-week history of left proptosis. Axial contrastenhanced CT images show an intensely enhancing intraconal mass in the left orbit.

Capillary hemangioma in a 9-week-old girl with right exophthalmos. (a) Axial T1-weighted image shows the lobular contour of an intraconal mass (arrowhead) with signal intensity similar to that of muscle and contrasted against the hyperintense conal fat. (b) Axial contrast-enhanced T1-weighted image with fat saturation demonstrates diffuse intense enhancement of the lobular mass.

Sagittal T2-weighted image also shows the hyperintense mass, which contains flow voids

The imaging differential

for hemangioma includes rhabdomyosarcoma, vascular malformations, infantile fibromatosis, or infantile fibrosarcoma.

The vascular features of hemangioma, particularly the flow voids on MR images, distinguish hemangioma from these other lesions. In rare cases, rhabdomyosarcoma may be so vascular as to contain flow voids , but rhabdomyosarcoma typically occurs in an older age group.

Venous-LymphaticMalformations (Lymphangiomas)

• Vascular malformations found in the orbit were originally called lymphangiomas by Jones in 1959 and that terminology persists to this day.

• The term, however, does not encompass the full clinical, radiologic, and histologic complexity of the lesion, which has both lymphatic and venous features. According to the Mulliken and Glowacki classification, these malformations are composed of a mixture of venous and lymphatic vessels and may be called combined venous-lymphatic malformations or lymphaticovenous malformations .

• Venous-lymphatic malformations of the orbit are associated with noncontiguous, ipsilateral, intracranial vascular anomalies.

Clinical Features.

• The malformations are present at birth, but they may not be discovered until they undergo expansion. Most patients present in early childhood.

• Venous-lymphatic malformations may involve superficial structures (conjunctiva and eyelid), the deeper structures of the orbit, or both. Those lesions that involve the superficial or anterior orbital structures are diagnosed earlier.

• Frequently, anterior lesions extend to the forehead, temporal region, and cheek.

Imaging Features• On US images, venous-lymphatic malformations appear

heterogeneous in echotexture with ill-defined borders. Anechoic cystic portions may predominate. Extraconal extension is frequent, so MR imaging or CT is necessary to evaluate the full extent of the lesion.

• CT is particularly sensitive for depicting the phleboliths that may be present in the venous component of these lesions .

• The density of the mass depends on the presence of hemorrhage. The mass is generally well visualized due to the inherent contrast between the malformation and orbital fat

• MR imaging is the preferred modality for evaluation of suspected venous-lymphatic malformation because it is most accurate at delineating the anatomic location of the lesion and its different vascular components

Venous-lymphatic malformation in a 9-year-old girl. Axial unenhanced CT image reveals a medial soft-tissue attenuation mass with calcification (arrowhead).

Venous-lymphatic malformation of the orbit and face with associated sinus pericranii and developmental venous anomaly. (a) Axial contrast-enhanced CT image shows a lobular intraconal mass on the left, which enhances as much as muscle. (b) Coronal contrast-enhanced CT image shows that some portions of the multilobular mass have enhancement features similar to those of muscle (arrowheads) and that another portions less enhancing (arrow).

(c) Coronal CT image shows abnormal veins along the walls of the lateral ventricles(arrowhead). (d) Coronal CT image (bone window) shows multiple bony defects of sinus pericranii in the left frontal bone (arrowhead) that allow anomalous venous drainage from the face to the intracranial venous structures

Dramatically enlarging venous-lymphatic malformation in a 9-year-old girl born with a left orbital mass (diagnosed at birth as a lymphangioma). (a) Axial T1-weighted image shows a multilobular mass with variedinternal signal intensity and a fluid-fluid level (arrow).(b) Axial T2-weighted image shows the multilobular lesionwith multiple fluid-fluid levels (arrowhead).

Axial proton-density–weighted image with fat saturation demonstrates the varied signal-intensity, multilobular mass with fluid-fluid levels (arrow)

Infantile Fibromatosis• The fibromatoses are a widely varied group of fibrous

proliferations that share several features: They are locally invasive, tend to recur after surgical resection, and do not metastasize.

• These conditions are divided into superficial and deep types, each containing multiple subtypes . One form of deep fibromatosis, infantile fibromatosis (also known as infantile myofibromatosis or juvenile fibromatosis) is the most common fibrous tumor of infancy

• Generally, infantile fibromatosis carries a favorable prognosis, as most lesions spontaneously resolve; however, multicentric disease with visceral involvement has a worse prognosis

Clinical Features

• Infantile fibromatosis occurs in infants and is often noted at birth.

• In both the solitary and multicentric forms, infantile fibromatosis may affect the skin, the subcutaneous tissues, deeper structures including visceral organs, or a combination of these.

• Deep lesions of the orbit most commonly manifest with proptosis

Imaging Findings• Plain radiography may show an expanded orbit, a

nonspecific finding.• US may show a round, well-circumscribed mass of

heterogeneous echotexture. A target appearance caused by central necrosis or hemorrhage may be noted

• At CT, infantile fibromatosis may manifest with orbital bone erosion

• MR imaging best demonstrates the extent of involvement in multicentric infantile fibromatosis and the relationship of solitary lesions to adjacent normal structures

Solitary form of juvenile fibromatosis in a 4-year old boy with painless swelling of the right lower eyelid.Axial CT image (bone window) shows erosion of the lateral wall of the orbit and an adjacent soft-tissue mass (arrowhead)Axial T1-weighted MR image demonstrates the well-circumscribed mass (arrowhead), which has signalintensity similar to that of muscle, invading the cortex of the adjacent bone.

Coronal contrast-enhanced T1- weighted image reveals the well-circumscribed mass with peripheral enhancement.

Juvenile fibrosarcoma in a 5-year-old boy with right eye swelling, pain, and erythema. (a) Axial contrast- enhanced CT image shows a right intraconal, slightly circumscribed mass (arrowhead) that enhances as much as extraocular muscle Axial T1-weighted MR image shows that the mass is well defined and slightly hyperintense relative to muscle and brain

Dd• The very rare infantile fibromatosis must be distinguished from

other more common conditions that may cause orbital masses.• If the patient has multicentric disease, the differential

diagnosis is limited. Metastatic neuroblastoma and Langerhans cell histiocytosis are multifocal conditions that may occur in infancy and involve soft tissues, bones, and viscera.

• Infantile fibromatosis with a solitary lesion of the orbit or periorbital soft tissues include more common tumors such as rhabdo and hemangioma ,the features of which have been already discussed

Thankyou