Case Report: Long-Term Chemotherapy With Hydroxyurea and Prednisolone in a Cat With a Meningioma: Correlation of FDG Uptake and Tumor Grade Assessed by Histopathology and Expression of Ki-67 and p53

Taesik Yun,Mhan-Pyo Yang,Hakhyun Kim,Soochong Kim,Wonguk Lee,Dong-In Jung,Yoonhoi Koo,Byeong-Teck Kang

doi:10.3389/fvets.2021.576839

Abstract

A 15.5-year-old, neutered, male, domestic shorthair cat was presented with neurologic dysfunctions. At presentation, an obtunded mental status and vestibular ataxia were identified. On neurologic examination, postural reactions were decreased-to-absent in all four limbs, and pupillary light reflexes showed bilaterally delayed results. Magnetic resonance imaging was performed, and a demarcated lesion was identified in the third ventricle. The cat was tentatively diagnosed with a brain tumor, which was suspected to be a meningioma. The cat was treated with hydroxyurea and prednisolone. Mental status was considered more alert, and ataxia improved following treatment. On the 106th day after the commencement of treatment, a 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) scan was performed. On the PET images, a hypermetabolic region was found in the lesion. The average standardized uptake value of FDG was 2.47, and the tumor-to-normal-tissue ratio was 1.25. The cat died 408 days following the commencement of treatment, and a grade 1 meningioma was confirmed by postmortem histopathology. Immunohistochemistry for Ki-67 and p53 was performed. The labeling indices of Ki-67 and p53 were 2.56 and 0%, respectively. This case shows that chemotherapy with hydroxyurea and prednisolone may be considered in the treatment of feline meningiomas. Furthermore, this is the first case describing the application of FDG-PET to visualize a naturally occurring meningioma in a cat.

Highlights

Meningiomas account for 58.1% of the CNS neoplasms and are the most common intracranial primary tumors in cats [1]
Some FDG-positron emission tomography (PET) characteristics of feline malignancy cases have been reported [11, 12], but there are no reports of FDG-PET findings in feline brain tumors
Since deranged glucose metabolism is a common feature in many malignant tumors, it is primarily used to identify metabolically active lesions for differentiation of benign and malignant tumors in pancreatic mass, pulmonary nodules, and remnant lesions after chemotherapy in lymphoma [8, 16]

Summary

INTRODUCTION

Meningiomas account for 58.1% of the CNS neoplasms and are the most common intracranial primary tumors in cats [1] They are generally benign, slowly progressing, mostly solitary, and originate from the meninges (arachnoid cells). The cat was initially treated with oral prednisolone (0.5 mg/kg twice daily; Solondo R , Yuhan, Seoul, South Korea) as a palliative therapy to decrease the intracranial pressure by relieving the tumor-associated brain edema [13] and decreasing cerebrospinal fluid production [14]. Immediately after the second MRI, we performed an FDGPET scan because it could identify malignancy and tumor metastasis, and because the FDG-PET findings of feline meningiomas have not been previously reported. The cat showed clinical deteriorations, including obtunded mental status and vestibular ataxia, on days 66, 221, and 320; the dose of prednisolone was adjusted based on worsening of clinical signs, while the hydroxyurea dosage was maintained.

DISCUSSION

Findings

DATA AVAILABILITY STATEMENT