Extraconal orbital tumors in children--a spectrum

Assessing the Usefulness of Ultrasonography for the Diagnosis and Evaluation of Intra-Orbital Lesions in Pediatric Patients: A Retrospective Analysis

OBJECTIVES

To assess the usefulness of ultrasonography in the diagnosis and evaluation of extraocular intra-orbital lesions in pediatric patients.

METHODS

Twenty-three pediatric patients with intra-orbital lesions who underwent both ultrasound and computed tomography/magnetic resonance imaging (CT/MRI) were included. The following parameters were evaluated using ultrasound: 1) lesion detection rate (presence or absence of lesions), 2) lesion characteristics, 3) lesion location (extraconal or intraconal), and 4) the lesion longest linear dimensions, and these were compared using Fisher's exact test and Mann-Whitney U test.

RESULTS

Two lesions could not be detected using ultrasound; in the other 21 cases, the lesion characteristics diagnosed by ultrasound were correct. Diagnostic accuracy of detection and characteristics assessment using ultrasound were 91.3% and 91.3%, respectively. The lesion location was not significantly different between the two groups (intraconal/extraconal in those detected using ultrasound versus those in the absence on ultrasound = 7/14 versus 0/2, P > .999); however, in two cases that were not detected on ultrasound, the lesions were located at extraconal. Lesions that were small in longest linear dimensions on CT/MRI were not detected using ultrasound (the longest linear dimensions in lesions detected using ultrasound versus that in the absence of ultrasound: 29.5 ± 8.2 [range, 13-46] versus 10 and 11 mm, P = .043).

CONCLUSIONS

Ultrasonography proved to be useful for visualizing and evaluating intra-orbital lesions except for lesions that were relatively small in size. Therefore, although ultrasound could not detect lesions located behind bone and bone invasion, it could be used for diagnosing and selecting treatment strategies for intra-orbital lesions.

Receptor tyrosine kinase gene expression profiling of orbital rhabdomyosarcoma unveils MET as a potential biomarker and therapeutic target

Receptor tyrosine kinases (RTKs) serve as molecular targets for the development of novel personalized therapies in many malignancies. In the present study, expression pattern of receptor tyrosine kinases and its clinical significance in orbital RMS has been explored. Eighteen patients with histopathologically confirmed orbital RMS formed part of this study. Comprehensive q-PCR gene expression profiles of 19 RTKs were generated in the cases and controls. The patients were followed up for 59.53 ± 20.93 years. Clustering and statistical analysis tools were applied to identify the significant combination of RTKs associated with orbital rhabdomyosarcoma patients. mRNA overexpression of RTKs which included MET, AXL, EGFR was seen in 60-80% of cases; EGFR3, IGFR2, FGFR1, RET, PDGFR1, VEGFR2, PDGFR2 in 30-60% of cases; and EGFR4, FGFR3,VEGFR3 and ROS,IGFR1, EGFR1, FGFR2, VEGFR1 in 10-30% of cases. Immunoexpression of MET was seen in 89% of cases. A significant association was seen between MET mRNA and its protein expression. In all the cases MET gene expression was associated with worst overall survival (P = 0.03).There was a significant correlation of MET mRNA expression with RET, ROS, AXL, FGFR1, FGFR3, PDGFR1, IGFR1, VEGFR2, and EGFR3 genes. Association between MET gene and collective expression of RTKs was further evaluated by semi-supervised gene cluster analysis and Principal component analysis, which showed well-separated tumor clusters. MET gene overexpression could be a useful biomarker for identifying high risk orbital rhabdomyosarcoma patients. Well-separated tumor clusters confirmed the association between MET gene and collective expression of RTK genes. Therefore, the therapeutic potential of multi-kinase inhibitors targeting MET and the 9 other significant RTKs needs to be explored.

MRI of Pediatric Orbital Masses: Role of Quantitative Diffusion-weighted Imaging in Differentiating Benign from Malignant Lesions

PURPOSE

To systematically evaluate the utility of different magnetic resonance imaging (MRI) features, including quantitative diffusion-weighted imaging, in differentiating benign from malignant pediatric orbital masses.

METHODS

The use of MRI in 40 pediatric patients with orbital masses was retrospectively reviewed. Multiple subjective and objective MRI parameters, including lesion mean apparent diffusion coefficient (ADC) values and lesion-to-thalamus ADC ratio were recorded. Bivariate analysis was done to identify parameters that were significantly different between benign and malignant subgroups. Receiver operating curves were used to establish optimal cut-off values for lesion mean ADC and lesion-to-thalamus ADC ratio for predicting benign versus malignant lesions.

RESULTS

Lesion mean ADC, lesion-to-thalamus ADC ratio and extent of contrast enhancement showed statistically significant differences between the two subgroups. For distinguishing benign from malignant lesions, a lesion mean ADC cut-off value of 1.14 × 10^-3 mm²/s provided a sensitivity of 84% and specificity of 100%, while an ADC ratio of 1.4 provided a sensitivity of 81% and specificity of 89%.

CONCLUSION

Quantitative diffusion-weighted imaging can be a useful adjunct in characterizing pediatric orbital masses by MRI, and thus help in clinical decision making.

Role of Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Various Orbital Malignancies

Orbital swelling comprises wide spectrum of pseudotumors, benign and malignant tumor. Malignant tumor may be primary or secondary tumor, and they constitute about 36% of orbital tumors in adult. Fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) scan is extensively used in hematological malignancies and in solid tumors for staging, treatment response, and restaging. Recently, the use of FDG-PET/CT in orbital malignancies has gained importance. The aim of this pictorial essay is to illustrate few important orbital malignancies detected in F-18 FDG-PET/CT and discuss its role in assessing the primary lesion and associated systemic finding.

Orbital rhabdomyosarcomas: A review

Rhabdomyosarcoma (RMS) is a highly malignant tumor and is one of the few life-threatening diseases that present first to the ophthalmologist. It is the most common soft-tissue sarcoma of the head and neck in childhood with 10% of all cases occurring in the orbit. RMS has been reported from birth to the seventh decade, with the majority of cases presenting in early childhood. Survival has changed drastically over the years, from 30% in the 1960's to 90% presently, with the advent of new diagnostic and therapeutic modalities. The purpose of this review is to provide a general overview of primary orbital RMS derived from a literature search of material published over the last 10 years, as well as to present two representative cases of patients that have been managed at our institute.

Visual function alterations in orbital tumors and factors predicting visual outcome after surgery

PURPOSE

To study the effect of orbital tumors on visual functions and highlight the factors predictive of visual outcome after surgery.

METHODS

A prospective interventional study compared visual function parameters and fundus changes, before and after surgery, in eyes having well-defined orbital tumors with the normal fellow eye. These included visual acuity (VA), refractive error, keratometry changes, color vision, Goldmann visual field (GVF), and visual evoked response (VER).

RESULTS

In total 28 cases (age range 7-56 years), of which the majority of tumors were vascular (46%) and lacrimal (18%) in origin, had a mean VA of 0.54±0.33 in the affected eye, which improved postoperatively to 0.66±0.31 (P=0.002). The affected eye had a median refractive error of +0.00 DS (-2.00 to 5.13), which was significantly more hyperopic than the normal eye (median +0.00 DS; range -1.25 to +1.63 DS) and normalized postoperatively. Keratometry showed higher astigmatism in the involved eye (P=0.004). The fundus showed disc pallor, edema, and/or choroidal folds, of which disc edema resolved in all cases after surgery. In all, 40% of the affected eyes had a deficient color vision and this partially improved postoperatively (P=0.25). GVF had abnormalities in 10 cases, half of which normalized postoperatively (P=0.04). The VER of affected eyes had a mean amplitude of 8.91±4.59 μv and latency of 116.3±14.7 ms, with improvement after surgery (P=0.005 and 0.001, respectively).

CONCLUSION

Orbital tumors adversely affected visual functions. The presenting acuity depended on disc changes, color vision abnormalities, and prolonged VER latency. The postoperative VA depended on VA at presentation, amount of proptosis, degree of hyperopia, and clinically significant VER abnormalities.

[Dermoid cyst in childhood, diagnosed as ptosis]

CLINICAL CASE

A four year-old boy, diagnosed of palpebral ptosis since he was 2 by his paediatrician. At the initial ophthalmological revies he had asymmetrical upper eyelids. In the follow-up a mild ocular hypotrophy appeared in his left eye and an increasing astigmatism, which made us suspect an orbital disease. The MRI confirmed a mass, compatible with a dermoid cyst.

CONCLUSION

Due to the slow growth of these tumours, it is only with clinical follow-up and the aid of imaging techniques that we may achieve the diagnosis and offer a definitive treatment with surgical extirpation.

[Granulocytic sarcoma, a diagnostic challenge: 3 pediatric cases]

Granulocytic sarcoma (GS) is a rare extramedullary tumor frequently associated with acute myeloblastic leukemia (AML). We report 3 cases of pediatric granulocytic sarcomas with various locations: skin, orbit, and bowel. Cases 1 and 2 were associated with AML; case 3 was isolated. In all 3 cases, the diagnosis was delayed or initially missed. Pathology and immunohistochemistry data identified the disease. GS is treated with chemotherapy, like AML. The prognosis of GS seems better than that of isolated AML.