Description:

• Well-defined cystic lesion in subcutaneous plane of lateral margins of orbit on left

• Underlying bone and adjacent lacrimal gland are unremarkable

Description:

Possible differential considerations include:

• Orbital dermoid cyst – TRUE

• Orbital teratoma – TRUE

• Orbital dermolipoma – TRUE

• Orbital hemangioma – TRUE

• Orbital rhabdomyosarcoma – FALSE

Dermoid cysts

• They are thought to occur as a developmental anomaly in which embryonic ectoderm and mesoderm are trapped in the closing neural tube between the 5th and 6th weeks of gestation

• These lesions are usually extraconal, non-enhancing masses with smooth margins, cystic, and/or solid components

• They are typically heterogeneous with soft tissue, fluid, and fatty (sebum) components; occasionally calcifications may be present

• They are most commonly located superotemporally, arising from the zygomaticofrontal suture, followed by superonasally, arising from the frontoethmoidal or frontolacrimal sutures

• Ruptured dermoids may show adjacent inflammatory changes

• Superficial lesions barely require cosmetic excision, while a deeper lesions may require more invasive methods involving micro-dissection and orbitotomy

References:

• Kudo K, Tsutsumi S, Suga Y et al. Orbital dermoid cyst with intratumoral inflammatory hemorrhage: case report. Neurol. Med. Chir. (Tokyo). 2008;48 (8): 359-62. Pubmed citation

• Ahmed RA, Eltanamly RM. Orbital epidermoid cysts: a diagnosis to consider. J Ophthalmol. 08;2014: 508425. doi:10.1155/2014/508425 – Free text at pubmed – Pubmed citation

• Chaudhry IA. Management of deep orbital dermoid cysts. Middle East Afr J Ophthalmol. 2008;15 (1): 43-5. doi:10.4103/0974-9233.53376 – Free text at pubmed – Pubmed citation

The case was initially interpreted as CSF seeding by a malignant choroid plexus tumor.

However, retrospective investigation of CTA showed another pathology.

• This case demonstrates several small areas of cortical enhancement in the right hemisphere. These enhancing areas correspond to small regions of subacute cortical ischemia in the right MCA territory, caused by a ruptured carotid plaque with an intraluminal thrombus. The mass in the antrum of the left ventricle is an incidental intraventricular meningioma. Follow-up scans showed regression of the cortical enhancement and stable intraventricular meningioma on the left.

• Teaching points:

• Subacute ischemia may enhance and in some cases mimic tumors or CSF seeding.

• Ruptured carotid plaque with intraluminal thrombus presents with finger-like filling defect of the internal carotid.

• Choroid plexus carcinomas are rare in elderly patients with an intraventricular meningioma being way more common. Typical location, sharp tumor-brain interface, homogeneous enhancement and T2 hypointensity allow for a confident diagnosis of an intraventricular meningioma.

What do you see?

TB cervical lymphadenitis

Mild progression in size of multiple necrotic lymph nodes in bilateral supraclavicular, axillary regions, internal yugular (more prominent at right side).