Papillary cores are lined by a 2-3 cell thick layer.
Prominent hyalinization of vessels is characteristic. A confluent growth of neoplastic ependymal cells is seen here.
Glial processes extend perpendicularly oriented toward the lumen, but the processes can be obscured by mucin. Note these rosette-like structures with mucin in their central cores.
A closer view of mucin accumulation and rosette like structures.
Strong GFAP staining highlights the glial nature of this tumor and help differentiate this entity from chordomas, metastatic papillary adenocarcinoma, paragangliomas or schwannomas.
Most ependymomas are WHO Grade II tumors, however, myxopapillary ependymoma is a distinct variant with more indolent clinical behavior. Thus, mxyopapillary ependymomas have low MIB-1 labeling and are categorized as WHO Grade I tumors.
Distinct features include the following: (1) Almost exclusively located in the filum terminale or cauda equina; (2) hyalinzed vessels; (3) abundant extracellular mucin; (4) papillary arrangement of fibrillary cells that extend their processes toward vascular lumens (i.e. perivascular pseudorosettes, but with papillary architecture)(Fletcher, Prayson).
Average age of presentation is in the 30s. Longstanding back pain is the most common complaint.
Excellent prognosis especially if resected intact. If mucoid material is spilled intraoperatively (i.e. capsule is disrupted), there is an increased risk of recurrence (Prayson).
Fletcher CDM, ed. Diagnostic Histopathology of Tumors. 3rd Ed. Philadelphia, PA: Elsevier; 2007: 1681.
Prayson, RA. Neuropathology: Foundations in Diagnostic Pathology. Philadelphia, PA: Elvesier; 2005: 474.
Prayson R, Kleinschmidt-Demasters BK, Cohen ML. Brain Tumors. Consultant Pathology Series New York, NY: Demos Publishing: 2010: 153-5.