Fine-Needle Aspiration Cytology of Metastatic Oligodendroglioma: Case Report and Literature Review

Abstract

Background: Systemic metastasis of a glial tumor is a rare event. However, metastatic cases are anticipated to increase due to prolongation of survival as a result of the development of new treatment modalities. The possibility of metastasis should be considered in patients with a history of a glial tumor rather than a second primary tumor. Fine-needle aspiration cytology is one of the diagnostic procedures primarily applied for confirmation of metastasis in cases with a known primary focus. Therefore, comprehensive knowledge of diagnostic cytomorphologic findings is required in these cases. Case Report: We report a young woman with oligodendroglioma metastasizing to the cervical lymphatic chain 5 years after initial diagnosis. Fine-needle aspiration cytology revealed a highly cellular smear with dispersed single cells and loosely cohesive cell clusters showing rosette-like features on a clean background. The relatively monotonous tumor cells were small sized and had round nuclei with moderate anisonucleosis and scant cytoplasm without extensions. Diagnostic confirmation was made by excisional biopsy and demonstration of 1p19q codeletion on tissue section by fluorescence in situ hybridization. Conclusion: A brief review of the literature with an emphasis on the cytologic features of metastatic oligodendroglioma and differential diagnosis with respect to other metastatic small round cell tumors is provided.

Intraoperative Frozen Cytology of Central Nervous System Neoplasms: An Ancillary Tool for Frozen Diagnosis

“…Round cell lesions such as oligodendroglioma containing abundant thin capillary structures may easily exclude astrocytic lesions due to a perinuclear halo artifact that is typically seen in permanent formalin-fixed processing of oligodendrogliomas [14,22]. Cytological smears of oligodendroglioma-mimicking round cell tumors such as central neurocytoma, hemangioblastoma, metastatic clear cell renal cell carcinoma, and dysembryoplastic neuroepithelial tumor should be differentiated from oligodendroglioma and small cell glioblastoma [23,24]. Central neurocytoma, an oligodendroglioma-mimicker, is a well-differentiated tumor showing features of neuronal differentiation that may mimic the frozen histology of oligodendroglioma, clear cell ependymoma, or even necrotic glioblastoma due to eosinophilic acellular fibrillary areas masquerading as necrotic portions under frozen histologic sections, despite the small round cells having fine, granular nuclear chromatin and cytoplasm [20,25].…”

Cervical Lymph Node Metastases from Central Nervous System Tumors: A Systematic Review

“…When a cervical LNM of CNS tumor is suspected, due to the patient’s history for example, fine needle aspiration cytology (FNAC) can clarify the diagnosis. 18 , 23 , 33 , 93 , 106 Yet, without a precedent of a brain tumor, the underlying diagnosis can be difficult, due to the fact that the tumor may be similar to a sarcoma, carcinoma, or a hematopoietic neoplasm. 3 In dubious cases, histologic examination of tissue obtained with core biopsy of suspicious lymph node is sometimes necessary to obtain a reliable diagnosis.…”

Cytology of Extraneural Metastases of Nonhematolymphoid Primary Central Nervous System Tumors: Six Cases with Histopathological Correlation and Literature Update

“…Specifically, ENM involving the head and neck region may mimic abnormalities of the salivary glands such as parotitis (esp. if associated with pyrexia, with rapid clinical development and in the immediate postoperative period) [9-11], a primary salivary gland neoplasm [7, 12], or other neoplastic processes [13] causing potential for delay in clinical management as well as unnecessary medical interventions. Lymph nodes incorporated into the parotid gland as a result of the gland’s embryological development, drain forehead, nasal root, upper lip, cheek, temple, and external ear.…”

“…One is the extremely rare manifestation of metastatic CNS tumors in serous effusions with [39] or without [40-42] prior shunt placement. The other is the rare occurrence of a substantially different, genuine, or preparation-related tumor morphology in ENM compared to the primary site [13]. No cases with malignant effusion were detected in our patient population, and only the glioblastoma with a primitive neuronal component in our series presented a diagnostic challenge from the perspective that no glial component was detectable in the sample obtained from the metastatic site, which may or may not have been the result of a preferential sampling by FNA.…”

“…If required, this relationship can be further supported with ancillary studies. The increasing identification and use of molecular parameters to define CNS tumor entities, although not necessary or available in any of the cases of our retrospective series, can prove extremely useful in this scenario [13, 32] and, consequently, more invasive diagnostic measures can be avoided. The exact mechanism(s) involved in extraneural tumor spread [45, 46] and, despite progress made in recent decades [47], more effective treatment options for cases with manifest ENM remain to be identified.…”