[Renal cell carcinoma presenting as paraneoplastic neurological dysfunction]

A Rare Coexistence of Paraneoplastic Cerebellar Degeneration: Papillary Thyroid Carcinoma

Paraneoplastic cerebellar degeneration (PCD) is a rare neuroimmunological disease that may accompany tumors. In this article, we present a patient with progressive gait difficulty who was diagnosed with PCD and, in a rare comorbidity, with papillary thyroid carcinoma (PTC) following malignancy screening. A 46-year-old male patient reported having experienced poor balance for 2 years. A neurological examination revealed nystagmus, intention tremor, and ataxia, and anti-thyroid peroxidase and anti-thyroglobulin levels were found to be elevated. A brain MRI showed significant cerebellar atrophy in the superior vermis. Malignancy screening for PCD was performed, and thyroid ultrasonography revealed a nodule in the left lobe, while PET/CT detected elevated focal F-18 fluorodeoxyglucose uptake in the thyroid. Onconeuronal antibodies (anti-Hu, anti-Yo, anti-Ri, anti-amphiphysin, anti-Tr, anti-PPCA-2, anti-Ma, anti-CV-1, and anti-ANNA-3) were negative. Pathologic examination of the thyroid revealed PTC, for which the patient was treated with 0.4 g/kg intravenous immunoglobulin and referred to the medical oncology department. This case demonstrates that clinicians must be alert to the rare comorbidity of PCD and PTC.

Paraneoplastic cerebellar degeneration as initial presentation of renal cell carcinoma

Background

Paraneoplastic cerebellar degeneration is usually associated with gynecological and breast cancer, lung cancer, and Hodgkin’s lymphoma. Renal cell carcinoma has rarely been described as an underlying malignancy in these cases.

Case presentation

We report the case of a 75 year-old woman who develop cerebellar ataxia following a respiratory viral infection. During investigation, around 1 year afterward, she noticed constitutional symptoms suggestive of malignancy. Renal carcinoma was found and the hypothesis of paraneoplastic cerebellar degeneration was considered.

Conclusions

As no specific antineuronal antibodies have been described in the setting of renal cell carcinoma, paraneoplastic cerebellar degeneration should be considered when the tumor is detected and other causes are excluded. Immunotherapy should be prescribed as soon as possible.