Answer for CoW 11 Feb 2018
Orbital lymphoma
Findings
Findings: Known case of systemic NHL on chemotherapy/ Left eye retinal detachment Bilateral T1 hypointense,T2 hyperintense lesion in the outer superolateral aspect (extraconal ) of orbit showing diffusion restriction and mild homogenous contrast enhancement. Eyeball: Retinal detachment noted in left eye. Brain screening: Gliosis noted in right temporal lobe.
Discussion
Orbital lymphoma represents a small fraction of all systemic lymphomas that account for approximately 1–2 % of non- Hodgkin lymphomas. Orbital lymphomas are a heterogeneous group of malignancies, most of them are primary extranodal lymphoma of the marginal zone of mucosa associated with lymphoid tissue (MALT type lymphoma). This tumour is seen more commonly in the 5th–7th decades of life with a slight female predominance. The orbital infiltration by lymphoma is characterised by a palpable, firm or rubbery mass. Other symptoms are progressive proptosis, decreased visual acuity, motility disturbances and diplopia. Direct infiltration of the globe and/or optic nerve is rare, and vision is usually preserved. The typical location consists of the involvement of superior quadrants;specifically, the superior-lateral one. The most commonly infiltrated structures are found within the superior-lateral quadrant, such as the superior rectus muscle, lateral rectus muscle, lacrimal gland and eyelid.Involvement of intra-conal space is usually associated with the extra-conal one, and is related with large size of the tumour. Therefore, an intra-conal involvement alone will not be the main pattern of lymphoma in the orbit. Radiological features: CT On non-contrast CT, the mass is usually homogeneous in density, either isodense or slightly hyperdense when compared to the extraocular muscles . Following administration of contrast, only mild to moderate enhancement is seen, similar again to the extraocular muscles and lacrimal gland. MRI Similar to intracranial lymphoma, the densely cellular nature of these tumours with high nucleus-to-cytoplasm ratio results in relatively specific appearances .Signal characteristics include: T1: iso- to hypointense to muscle T2: iso- to hyperintense to muscle T1 C+ (Gd): homogeneous enhancement DWI: increased signal intensity - restricted diffusion ADC: reduced values - restricted diffusion. Differential diagnosis: For masses involving the intra- and extra-conal compartment should include inflammatory/metabolic disease (orbital inflammatory pseudotumour, thyroid orbitopathy, sarcoidosis) and neoplasm (lacrimal tumours, lymphoma and metastasis).Exceptional diseases—such as Sjögren, Wegener,and Kimura diseases—are just mentioned. Inflammatory pseudotumours are often associated with fat tissue infiltration or oedema. Hypointense T2 signal is a helpful feature in order to differentiate from other tumours. Extraorbital extension has been reported . Variable contrast enhancement is described, although dual-phase contrasted CT reported an increased density on delayed images . Thyroid orbitopathy consist in thickened muscles bellies over 4 mm. Common rectus muscles involved are inferior, medial, superior and lateral . The tendinous insertion is usually not involved. Prominent intra-conal fat can also result in proptosis. Sarcoidosis is a non-caseating granulomatous inflammation. Diffuse infiltration of orbital structures and dural thickening is identified . Finally, any malignant tumour may metastasise within the orbit. Characteristic finding may be hyperintensity on T2-weighted imaging and heterogeneous enhancing mass. Bone destruction can occur . Lacrimal gland lesions can be classified into epithelial and non-epithelial. Epithelial tumours can be benign (pleomorphic adenoma) or malignant (pleomorphic adenocarcinoma). Carcinomas have heterogeneous signal intensity on T1- and T2-weighted images. Scalloped remodelling of bone structures and punctate calcification are occasionally identified.
References: 1. Priego G, Majos C, Climent F, Muntane A. Orbital lymphoma: imaging features and differential diagnosis. Insights into Imaging. 2012;3(4):337-344. doi:10.1007/s13244-012-0156-1. 2. Radiopaedia.org
Findings
Findings: Known case of systemic NHL on chemotherapy/ Left eye retinal detachment Bilateral T1 hypointense,T2 hyperintense lesion in the outer superolateral aspect (extraconal ) of orbit showing diffusion restriction and mild homogenous contrast enhancement. Eyeball: Retinal detachment noted in left eye. Brain screening: Gliosis noted in right temporal lobe.
Discussion
Orbital lymphoma represents a small fraction of all systemic lymphomas that account for approximately 1–2 % of non- Hodgkin lymphomas. Orbital lymphomas are a heterogeneous group of malignancies, most of them are primary extranodal lymphoma of the marginal zone of mucosa associated with lymphoid tissue (MALT type lymphoma). This tumour is seen more commonly in the 5th–7th decades of life with a slight female predominance. The orbital infiltration by lymphoma is characterised by a palpable, firm or rubbery mass. Other symptoms are progressive proptosis, decreased visual acuity, motility disturbances and diplopia. Direct infiltration of the globe and/or optic nerve is rare, and vision is usually preserved. The typical location consists of the involvement of superior quadrants;specifically, the superior-lateral one. The most commonly infiltrated structures are found within the superior-lateral quadrant, such as the superior rectus muscle, lateral rectus muscle, lacrimal gland and eyelid.Involvement of intra-conal space is usually associated with the extra-conal one, and is related with large size of the tumour. Therefore, an intra-conal involvement alone will not be the main pattern of lymphoma in the orbit. Radiological features: CT On non-contrast CT, the mass is usually homogeneous in density, either isodense or slightly hyperdense when compared to the extraocular muscles . Following administration of contrast, only mild to moderate enhancement is seen, similar again to the extraocular muscles and lacrimal gland. MRI Similar to intracranial lymphoma, the densely cellular nature of these tumours with high nucleus-to-cytoplasm ratio results in relatively specific appearances .Signal characteristics include: T1: iso- to hypointense to muscle T2: iso- to hyperintense to muscle T1 C+ (Gd): homogeneous enhancement DWI: increased signal intensity - restricted diffusion ADC: reduced values - restricted diffusion. Differential diagnosis: For masses involving the intra- and extra-conal compartment should include inflammatory/metabolic disease (orbital inflammatory pseudotumour, thyroid orbitopathy, sarcoidosis) and neoplasm (lacrimal tumours, lymphoma and metastasis).Exceptional diseases—such as Sjögren, Wegener,and Kimura diseases—are just mentioned. Inflammatory pseudotumours are often associated with fat tissue infiltration or oedema. Hypointense T2 signal is a helpful feature in order to differentiate from other tumours. Extraorbital extension has been reported . Variable contrast enhancement is described, although dual-phase contrasted CT reported an increased density on delayed images . Thyroid orbitopathy consist in thickened muscles bellies over 4 mm. Common rectus muscles involved are inferior, medial, superior and lateral . The tendinous insertion is usually not involved. Prominent intra-conal fat can also result in proptosis. Sarcoidosis is a non-caseating granulomatous inflammation. Diffuse infiltration of orbital structures and dural thickening is identified . Finally, any malignant tumour may metastasise within the orbit. Characteristic finding may be hyperintensity on T2-weighted imaging and heterogeneous enhancing mass. Bone destruction can occur . Lacrimal gland lesions can be classified into epithelial and non-epithelial. Epithelial tumours can be benign (pleomorphic adenoma) or malignant (pleomorphic adenocarcinoma). Carcinomas have heterogeneous signal intensity on T1- and T2-weighted images. Scalloped remodelling of bone structures and punctate calcification are occasionally identified.
References: 1. Priego G, Majos C, Climent F, Muntane A. Orbital lymphoma: imaging features and differential diagnosis. Insights into Imaging. 2012;3(4):337-344. doi:10.1007/s13244-012-0156-1. 2. Radiopaedia.org
Note:
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!