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

CSF cytology of common primary CNS neoplasms categorized by CNS WHO 2021

OBJECTIVE

The detection of neoplastic cells in cerebral spinal fluid (CSF) is pivotal for the management of patients with central nervous system (CNS) tumours. This article delves into the CSF cytological characteristics of common CNS neoplasms, aligning with the 2021 World Health Organization (WHO) classification of CNS tumours.

METHODS

A retrospective review of CSF specimens positive for primary CNS neoplasms was performed at three tertiary medical centres. Only cases that had histopathologic confirmation and/or molecular workup were included.

RESULTS

Common primary CNS neoplasms seen in CSF cytology specimens include medulloblastoma, (non-WNT/non-SHH as well as SHH-activated and TP53 mutant), pineoblastoma, atypical teratoid/rhabdoid tumour (AT/RT), IDH-wildtype glioblastoma, and primary diffuse large B-cell lymphoma of the CNS. Ependymomas and germinomas can also have CSF involvement but are less common. Although the typical histologic architecture of these tumours may not be preserved in the CSF, unique cytomorphologic features such as nuclear moulding, nuclear pleomorphism, rhabdoid cells, prominent nucleoli and rosette formation can still be appreciated.

CONCLUSION

Adopting the updated terminology and correlating cytologic observations with molecular findings will streamline the diagnostic process, reducing the complexities and ambiguities pathologists often encounter when analysing CSF specimens for potential primary CNS neoplasms.

Intracranial medulloblastoma as the cause of progressive ataxia in a 6-month-old draft horse cross gelding

We describe the unique clinical presentation of a central nervous system neoplasm in a 6-month-old draft horse cross gelding. Based on the neurologic examination at admission, neurolocalization was most consistent with a mildly asymmetric cervical, multifocal, or diffuse myelopathy. Mild vestibular involvement also was considered, but no cranial nerve deficits were observed. The gelding was negative for Sarcocystis neurona or Neospora hughesi based on paired serum and cerebrospinal fluid (CSF) samples analyzed, with no evidence of cervical compression based on contrast myelography. The horse was euthanized because of progression of clinical signs. At necropsy, a mass was identified associated with the cerebellum, and histopathology was consistent with medulloblastoma, which has not been reported previously in the horse.

Malignant invasion of the cerebrospinal fluid in adult and paediatric patients with haematological and solid malignancies: a monocentric retrospective study

OBJECTIVES

In this study, we describe the clinical presentation, the cerebrospinal fluid (CSF) characteristics and outcome of children and adults with leptomeningeal invasion due to haematological and solid malignancies.

METHODS

Routine CSF samples analyzed from 2008 to 2018 at our institution were retrospectively reviewed for the presence of malignant cells based on cytomorphological analysis.

RESULTS

Leptomeningeal invasion was identified in 212 patients: 45 children versus 167 adults, and 92 haematological versus 120 solid malignancies. Leukaemic invasion in childhood was mainly due to ALL, and lymphoma invasion was often due to a high-grade B-cell lymphoma in adults. Metastatic invasion by solid tumours was almost exclusively seen in adults. Patients suffered most frequently from cranial neuropathy and headache (both 32%), while asymptomatic presentations were seen mainly in children (33%) and haematological malignancies (17%). Laboratory CSF parameters often showed an elevated WBC count (87%), total protein (74%) and lactate (76%) and a decreased glucose (77%). These deviations were especially found in solid malignancies (>84%) and adults (>82%). Brain and/or spinal cord imaging was more often suggestive for the leptomeningeal invasion in solid than in haematological malignancies (86% vs. 46%). The 5-year overall survival (OS) rates for patients with haematological and solid malignancies were 21.5% and 5.9%, respectively. The 5-year OS rate for children (55.6%) was significantly better than for adults (3.5%).

CONCLUSION

Leptomeningeal invasion is more often asymptomatic, and CSF parameters and imaging are more often normal in children and haematological malignancies than in adults and solid malignancies, possibly leading to underdiagnosis.

Relapsed Medulloblastoma in Pre-Irradiated Patients: Current Practice for Diagnostics and Treatment

Relapsed medulloblastoma (rMB) accounts for a considerable, and disproportionate amount of childhood cancer deaths. Recent advances have gone someway to characterising disease biology at relapse including second malignancies that often cannot be distinguished from relapse on imaging alone. Furthermore, there are now multiple international early-phase trials exploring drug-target matches across a range of high-risk/relapsed paediatric tumours. Despite these advances, treatment at relapse in pre-irradiated patients is typically non-curative and focuses on providing life-prolonging and symptom-modifying care that is tailored to the needs and wishes of the individual and their family. Here, we describe the current understanding of prognostic factors at disease relapse such as principal molecular group, adverse molecular biology, and timing of relapse. We provide an overview of the clinical diagnostic process including signs and symptoms, staging investigations, and molecular pathology, followed by a summary of treatment modalities and considerations. Finally, we summarise future directions to progress understanding of treatment resistance and the biological mechanisms underpinning early therapy-refractory and relapsed disease. These initiatives include development of comprehensive and collaborative molecular profiling approaches at relapse, liquid biopsies such as cerebrospinal fluid (CSF) as a biomarker of minimal residual disease (MRD), modelling strategies, and the use of primary tumour material for real-time drug screening approaches.

Malignant ascites occurs most often in patients with high-grade serous papillary ovarian cancer at initial diagnosis: a retrospective analysis of 191 women treated at Bayreuth Hospital, 2006-2015

BACKGROUND

Malignant ascites often develops in patients with ovarian cancer, but there is a lack of more detailed characterization of the different histological subtypes.

METHODS

Ascites specimens from patients with ovarian cancer who were treated at Bayreuth Hospital from 2006 to 2015, with follow-up until December 2016, were reevaluated retrospectively.

RESULTS

A total of 191 women (mean age 64 years, range 48-79) were included, of whom 180 (94.2%) had carcinoma, three (1.6%) had malignant mixed müllerian tumors (MMMTs), four (2.1%) had sex cord-stromal tumors (SCSTs), three (1.6%) had germ cell tumors (GCTs), and one (0.5%) had a sarcoma. The carcinoma group comprised 134 (70.1%) patients with high-grade serous papillary ovarian cancer, 17 (8.9%) with low-grade serous papillary ovarian cancer, 10 (5.3%) with mucinous carcinomas, nine (4.7%) with endometrioid carcinomas, six (3.1%) with clear cell carcinomas, and four (2.1%) with neuroendocrine tumors. The latter group consisted of two patients with mixed neuroendocrine-nonneuroendocrine tumors (MiNENs), one with only a small cell carcinoma (SCCO), and one with a mucinous carcinoid. The noncarcinomatous group of eight patients (4.2%) included three (1.6%) with Sertoli-Leydig cell tumor and mature cystic teratoma (MCT), one (0.5%) with a granulosa cell tumor, and one with a leiomyosarcoma. A statistically significant difference in the proportion of patients with malignant ascites was observed, at 17.7% (3/17) in those with low-grade serous papillary ovarian cancer and 91.8% (123/134) in those with high-grade serous papillary ovarian carcinomas. In both patients with MiNEN, the glandular tumor cell component was found in the ascites. Tumor cells were found in the ascitic fluid in 50% (5/10) of patients with mucinous ovarian carcinomas, 16.7% (1/6) of those with clear cell carcinomas, and 33.3% (1/3) of those with MMMTs. The two patients (2/3; 66.7%) with neoplastic squamous cell components in MCT and the only patient with a granulosa cell tumor in the SCST group (1/4; 25%) had malignant cell populations in the ascites, whereas patients with endometrioid cell carcinoma and leiomyosarcoma lacked tumor cells in the ascites. The malignant ascites was detected at the initial diagnosis in all 138 (100%) patients with ovarian neoplasms.

CONCLUSIONS

High-grade serous papillary ovarian cancer was the main histological subtype most frequently found in ascites fluid in this series. The significant difference (P < 0.00001) in the malignancy rate in comparison with low-grade serous papillary carcinoma confirms the histological distinction between the two entities. Initial evidence of ovarian cancer in ascites fluid allows correct primary diagnosis in cytology specimens and is important for staging and prognosis.

Overview of cerebrospinal fluid cytology

Cerebrospinal fluid (CSF) cytology, i.e., the cytologic evaluation of its cellular composition, forms an integral part of the neurologist's armamentarium. Total and differential cell counts provide important first information across a spectrum of pathologic conditions involving the central nervous system and its coverings. CSF samples require immediate processing, ideally within 1 hour from collection. Upon centrifugation cytology is commonly assessed on May-Grunwald-Giemsa stains. Several additional stains are available for the identification of infectious agents such as bacteria or fungi, or the further specification of neoplastic cells by immunocytochemistry. The evaluation warrants familiarity with cytologic characteristics of cells across normal and diseased states. In normal CSF, lymphocytes and monocytes are encountered. A predominance of neutrophil granulocytes suggests bacterial meningitis and prompts search for intracellular bacteria. In contrast, in viral and chronic infections lymphocytes and monocytes prevail. Upon activation lymphocytes typically enlarge and eventually differentiate into plasma cells. Similarly, monocytes differentiate into macrophages that clear cellular debris. Macrophages that contain fragments of erythrocytes or hemoglobin degradation products are referred to as erythro- or siderophages, both of which indicate prior subarachnoid hemorrhage. Likewise, the detection of tumor cells is specific for neoplastic meningitis, although false-negative CSF cytologies are frequent. In summary, detailed morphologic workup of CSF samples provides valuable diagnostic information and is mandated in all cases with elevated cell count, computed tomography-negative suspected subarachnoid hemorrhage, and neoplastic meningitis. In all cases it needs to be interpreted in the clinical context and complements other clinical and laboratory findings.