CSF Involvement by Nonhematolymphoid Malignancies: A Descriptive Study with Emphasis on Cytomorphological Clues

Area of Science:

• Neuropathology
• Cytopathology
• Oncology

Background:

• Cerebrospinal fluid (CSF) analysis is vital for diagnosing central nervous system malignancies.
• Non-hematolymphoid malignancies involving the CSF are less common but critical to identify.
• Accurate cytomorphologic characterization aids in patient management and prognosis.

Purpose of the Study:

• To investigate the cytomorphologic features of non-hematolymphoid malignancies in CSF samples.
• To evaluate the diagnostic utility of CSF cytology for detecting these rare malignancies.
• To correlate cytomorphologic findings with primary tumor types and clinical outcomes.

Main Methods:

• Retrospective analysis of 27 CSF cytology smears positive or suspicious for non-hematolymphoid malignancies (2010-2020).
• Cytospin preparation with May-Grunwald-Giemsa and Papanicolaou staining.
• Immunohistochemistry/immunocytochemistry performed on available cell blocks or extra slides.

Main Results:

• 24 of 27 cases were positive for malignancy; 3 were suspicious.
• Metastatic adenocarcinomas constituted 19 cases (breast, stomach, lung, etc.), with 4 unknown primaries.
• Other malignancies included metastatic medulloblastoma (5), pineoblastoma (2), and extraskeletal Ewing sarcoma (1).
• Diagnostic cytomorphologic clues were present in all cases, consistent with other body fluid analyses.

Conclusions:

• Non-hematolymphoid malignancies are frequently metastatic and diagnosable via CSF cytology.
• Identification of malignant cells in CSF has significant therapeutic and prognostic implications.
• CSF cytology is a valuable tool for detecting these malignancies, guiding patient care.