Rosenthal fiber
Pronunciation: RO-zen-thal
Eosinophilic, elongated cytoplasmic inclusion in astrocytes, characteristic of pilocytic astrocytomas and Alexander disease.
Full Definition
A pathognomonic cytoplasmic inclusion found within astrocytic processes, appearing as thick, eosinophilic, corkscrew-shaped or elongated structures in routine histological sections. These fibers contain glial fibrillary acidic protein (GFAP), alpha-B-crystallin, and heat shock proteins, representing stress-related protein aggregates. While most characteristically associated with pilocytic astrocytomas, Rosenthal fibers are also the hallmark feature of Alexander disease, a rare leukodystrophy caused by GFAP gene mutations. Additionally, they may be observed in longstanding gliosis and around craniopharyngiomas. For editors reviewing neuropathology manuscripts, proper capitalization of this eponymous term and accurate description of associated pathological contexts are essential for maintaining scientific precision.
Usage
Usage note: Capitalize as eponymous term; often used in plural form as diagnostic criterion.
In Context
- "Abundant Rosenthal fibers were identified throughout the tumor, supporting the diagnosis of pilocytic astrocytoma." — Pathology report
- "The presence of Rosenthal fibers in white matter astrocytes raised suspicion for Alexander disease." — Case study