Paraneoplastic cerebellar degeneration associated with cerebellar hypermetabolism: Case report

Abstract

Rationale: Paraneoplastic cerebellar degeneration (PCD) is an immune-mediated neurological deficit affecting the cerebellum. Anti-Yo antibody positive PCD is a rare occurrence most likely associated with gynecologic or breast malignancies. The identification of the underlying tumor is a diagnostic challenge in many of these patients.

Patient concerns: We present a 68-year-old woman with acute symptoms of PCD as a first sign of underlying occult malignancy. Further investigation revealed a positive anti-Yo antibody. Although brain magnetic resonance imaging (MRI) was unremarkable, positron emission tomography (PET)/computed tomography (CT) revealed intense hypermetabolism of cerebellum and diffused hypometabolism in the rest of brain. On 1-year follow-up, despite the primary malignancy is still unknown, her symptoms improved significantly after immunotherapy.

Diagnoses: Paraneoplastic cerebellar degeneration.

Interventions: The patient was given IV methylprednisolone 500 mg once a day for 5 consecutive days, followed by oral prednisone 60 mg once a day for 3 months.

Outcomes: The patient's symptoms were gradually improved during the hospitalization period. On one year follow up, she was able to walk independently and perform some simple tasks.

Lessons: Cerebellar hypermetabolism in PCD suspected patients may help confirming the diagnosis in an earlier stage and may predict a better outcome after immunotherapy.

Figure 1

Transversal cranial MRI reveals no abnormal finding (A, B); Immunohistochemistry of right axillary lymph nodes reveals metastatic cancer cells from unknown origin (C).

Figure 2

PET/CT images show intense metabolic activity in the cerebellum associated with hypometabolism in the rest of brain (A, B); Right-sided axillary lymph nodes hypermetabolism with the absence of breast tissue hypermetabolism (C); significant metabolic activity in the intestine (D).

Figure 3

FDG-PET (A) reveals abnormal hot spots in the pelvic (black arrow) and axillary (blue arrow) regions. Coronal PET-CT (B) demonstrates abnormal increased glucose utilization in 2 different regions (white arrow indicates right axillary lymph node hypermetabolism; green arrow indicates significant intestinal hypermetabolism).