Cytologic characterization of atypical teratoid/rhabdoid tumor in cerebrospinal fluid

Abstract

BACKGROUND: Atypical teratoid/rhabdoid tumor (AT/RT) is a rare and highly aggressive intracranial malignancy with a predilection to spread along the cerebrospinal fluid (CSF) pathways. To the authors' knowledge, the cytopathologic characteristics of this tumor have not been extensively studied in CSF. Herein the authors report CSF cytomorphology from a series of patients with histologically documented AT/RT. METHODS: A retrospective review of 40 malignant CSF specimens from 10 patients with histologically confirmed AT/RT was conducted. All the patients were female and ranged in age from 0.8 to 19.6 years at the time of the initial diagnosis (median age, 1.3 years). Cytospin preparations were reviewed. In the majority of cases, at least 2 slides were prepared with the Wright-Giemsa and/or Papanicolaou stains. RESULTS:The CSF samples were predominantly moderately to highly cellular (80%). The 3 most common features were eccentrically placed nuclei (72.5%), prominent nucleoli (70%), and large tumor cells (67.5%). Two principal malignant cell types were noted; the most striking and recognizable form was a large, usually rhabdoid cell with an eccentrically placed nucleus, prominent nucleolus, and abundant cytoplasm, which was observed in 47.5% of the cases. The second type had a small cell appearance and was noted in 57.5% of the cases. Both large rhabdoid and small malignant cells were reported in 25% of the cases.

Cytomorphologic and clinicoradiologic analysis of primary nonhematologic central nervous system tumors with positive cerebrospinal fluid

“…B and D). It is interesting to note that in the AT/RT cases in the current study, we did not identify the gigantic cells (measuring >30 µm) that were noted in a study by Huang et al The discrepancy could perhaps be explained by the relatively small sample size examined in both studies.…”

“…Virtually all types of primary CNS tumors can metastasize to leptomeninges and the subarachnoid space, regardless of the histologic grading. Nevertheless, positive CSF cytology is observed for the most part in malignant embryonal neoplasms such as medulloblastomas, supratentorial primitive neuroectodermal tumors (PNETs), and atypical teratoid/rhabdoid tumors (AT/RTs) . These tumors are known to spread by leptomeningeal extension.…”

“…Occasionally, CSF seeding can occur in high‐grade infiltrating gliomas or ependymomas . Unlike direct leptomeningeal involvement of embryonal tumors, the mechanism of CSF metastasis in glial neoplasms is believed to be exfoliation of tumor cells into the subarachnoid space . As a result of CSF seeding, “drop metastases” can develop throughout the neuraxis.…”

Young investigator challenge: Cytomorphologic analysis of cerebrospinal fluid in 70 pediatric patients with medulloblastoma and review of the literature focusing on novel diagnostic and prognostic tests

“…Astrocytoma of the pilocytic subtype and glioblastoma are rare diagnoses and have distinctive neuroimaging patterns, whereas atypical teratoid/rhabdoid tumors enter into the differential diagnosis mainly because of cerebellar localization. Clues about the correct diagnosis include the following: atypical teratoid/rhabdoid tumor cells are classically described with rhabdoid features; granular, eosinophilic, abundant cytoplasm; eccentric‐placed nucleus, and prominent nucleoli as well as loss of nuclear expression of protein INI1 (a novel zinc‐finger protein) . Differential diagnoses in midline tumors, such as ependymomas and germinomas, can be very challenging, although infrequent because of the scant propensity of these tumors to exfoliate .…”

“…Clues about the correct diagnosis include the following: atypical teratoid/rhabdoid tumor cells are classically described with rhabdoid features; granular, eosinophilic, abundant cytoplasm; eccentric-placed nucleus, and prominent nucleoli as well as loss of nuclear expression of protein INI1 (a novel zinc-finger protein). 16 Differential diagnoses in midline tumors, such as ependymomas and germinomas, can be very challenging, although infrequent because of the scant propensity of these tumors to exfoliate. 15,17 In ependymoma, cells exhibit epithelioid features with eccentrically placed nuclei and abundant cytoplasm, whereas crowding and overlapping nuclei are frequent, but molding is absent.…”