Diktyoma

Diktyoma
Histopathology of medulloepithelioma showing characteristic neural tube like strands.
Classification and external resources
ICD-O	M9501/3
MeSH	D018242
[]

Diktyoma, or ciliary body medulloepithelioma, or teratoneuroma, is a rare tumor arising from primitive medullary epithelium in the ciliary body of the eye. Almost all diktyomas arise in the ciliary body, although, rarely, they may arise from the optic nerve head or retina.

The name "diktyoma" comes from its characteristic findings on histology.

Diktyoma is classified into teratoid and nonteratoid types, based on heteroplastic tissue in the former. Each type may be sub-classified as benign or malignant based on histology.

Based on histology, the tumor is classified as malignant if it contains poorly differentiated neuroblasts, nuclear pleomorphism, markedly abnormal mitotic activity, sarcomatous components, or invasion into the uvea, cornea, or sclera. Most diktyomas are malignant.

The most common symptoms of diktyoma are vision loss and pain, while the most common signs are leukocoria and presence of a mass in the iris or ciliary body. Other signs and symptoms include lens subluxation, glaucoma, cataract, exophthalmos, buphthalmos, strabismus, and ptosis.

Imaging studies such as ultrasonography (US), Computerized Tomography (CT) and Magnetic Resonance Imaging (MRI) may aid diagnosis. On ultrasound, diktyomas typically appear as echogenic, irregularly shaped to ovoid masses. Ultrasound is excellent for demonstrating cystic collections of vitreous fluid in the tumor, and may show calcifications in the teratoid type.

...
Wikipedia