Metastatic renal cell carcinoma mimicking a schwannoma in a dorsal root ganglion: case report

Neoplastic nerve lesions

Though metastasis and malignant infiltration of the peripheral nervous system is relatively rare, physicians should have a familiarity with their presentations to allow for prompt diagnosis and initiation of treatment. This article will review the clinical presentations, diagnostic evaluation, and treatment of neoplastic involvement of the cranial nerves, nerve roots, peripheral nerves, and muscle. Due to the proximity of the neural structure traversing the skull base, metastasis to this region results in distinctive syndromes, most often associated with breast, lung, and prostate cancer. Metastatic involvement of the nerve roots is uncommon, apart from leptomeningeal carcinomatosis and bony metastasis with resultant nerve root damage, and is characterized by significant pain, weakness, and numbness of an extremity. Neoplasms may metastasize or infiltrate the brachial and lumbosacral plexuses resulting in progressive and painful sensory and motor deficits. Differentiating neoplastic involvement from radiation-induced injury is of paramount importance as it dictates treatment and prognosis. Neurolymphomatosis, due to malignant lymphocytic infiltration of the cranial nerves, nerve roots, plexuses, and peripheral nerves, deserves special attention given its myriad presentations, often mimicking acquired demyelinating neuropathies.

Deceptive Features on Surveillance Imaging of Intraneural Metastatic Deposits in Metastatic Renal Cell Cancer

BACKGROUND

Spinal renal cell metastases are a common insidious pathological manifestation of the oncological process but less common are intramedullary and intraneural spinal metastases. The differential diagnosis of such pathological features can be difficult in the presence of conflicting radiological evidence.

CASE DESCRIPTION

In the present case report, we have detailed the clinical, diagnostic, surgical, and therapeutic progression of a 54-year-old man diagnosed with metastatic renal cell carcinoma. After the initial presentation and treatment, he had presented with symptomatic right lower limb radiculopathy. Magnetic resonance imaging identified a well-defined cystic lesion expanding in the right exit foramina at L5-S1, suggestive of a benign schwannoma. After a multidisciplinary review, he was treated symptomatically and imaging surveillance for a 19-month period, with static lesion findings. Failure of symptomatic management resulted in operative intervention and subsequent histological diagnosis of the metastatic deposit.

CONCLUSION

To the best of our knowledge, the present report is the first documented case of intraneural metastatic deposits from renal cell carcinoma that showed benign radiographic features and demonstrated a stable appearance on surveillance imaging studies for a significant period. These findings suggest that clinicians should have a high index of suspicion for a metastatic process in symptomatic patients with a known renal cell cancer regardless of the lesion's radiographic or temporal characteristics.

The repair using a fibular graft of cervical vertebral collapse due to renal cell carcinoma: Late results with a case report

The most common cause of spinal tumors is metastases, but the cervical vertebra is the least common region of spinal metastasis, and relatively, little is published about surgery in metastasis to the cervical vertebra. While spinal metastasis is most often caused by neoplasms originating from the lung, breast, and prostate, renal cell carcinoma (RCC) metastasis is very rare. A 47-year-old patient introduced here presented with severe pain spontaneously on his neck and in his arm. In the radiology of the patient without neurological deficit, a pathologic vertebral collapse was detected in the C6 vertebral corpus. The patient underwent anterior cervical corpectomy. The fibula graft taken from his right leg was implanted in the emptied area and supported by an anterior plaque, and restoration of physiological cervical lordosis was established. From the pathological tissue that was taken, it was determined that the cause of the lysis was an RCC metastasis. After surgical repair of the cervical spine, a primary pathology with a diameter of 10 cm was detected in the patient's kidney, and a radical nephrectomy was performed. After 6 years of follow-up, there was no recurrence, and the patient continued his normal daily life. Radiologically between the autologous fibula graft and its own vertebral body was observed to achieve very good fusion. In this study, we emphasized the importance of resection of metastasis together with a primary tumor in a metastatic RCC case to cure the patient and provide the desired quality of life.

The Challenges of Renal Cell Carcinoma Metastatic to the Spine: A Systematic Review of Survival and Treatment

STUDY DESIGN

Systematic review.

OBJECTIVES

The objective of this systematic review was to answer 2 key questions: (1) What is the clinical presentation and probability of symptomatic improvement following treatment for patients with renal cell carcinoma (RCC) of the spine? (2) What is the overall survival of patients diagnosed with spinal metastases from RCC?

METHODS

A literature review was performed to identify articles that reported on survival, clinical outcomes, and/or prognostic factors in the RCC population with spinal metastases from 1986 to 2016.

RESULTS

Forty-eight articles (807 patients) were included. The Fuhrman Nuclear Grade has been significantly associated with survival in previous studies but was underpowered in the current study. The Memorial Sloan-Kettering Cancer Center Score (MSKCC/Motzer) was also underpowered in the current study. From the time of spinal metastasis, the mean and median survival for patients with previously diagnosed primary RCC was 8.75 and 11.7 months, respectively, whereas synchronously diagnosed patients (primary RCC and spinal metastasis) had a mean and median survival of 6.75 and 11 months, respectively. Patients with a "low" (0-8), "intermediate" (9-11), or "high" (12-15) revised Tokuhashi score at initial presentation had a median survival of 5.4, 11.7, and 32.9 months, respectively.

CONCLUSION

Patients with either a synchronous or latent diagnosis of RCC survived greater than 6 months from the time of presentation. Initial Furhman grade, Tokuhashi score, and MSKCC/Motzer can be useful tools in informing patient-specific prognosis for those with metastatic RCC of the spine.

Plexus and peripheral nerve metastasis

Cancer in the form of solid tumors, leukemia, and lymphoma can infiltrate and metastasize to the peripheral nervous system, including the cranial nerves, nerve roots, cervical, brachial and lumbosacral plexuses, and, rarely, the peripheral nerves. This review discusses the presentation, diagnostic evaluation, and treatment options for metastatic lesions to these components of the peripheral nervous system and is organized based on the anatomic distribution. As skull base metastases (also discussed in Chapter 14) result in cranial neuropathies, these will be covered in detail, as well as cancers that directly infiltrate the cranial nerves. Particular emphasis is placed on the clinical, imaging, and electrodiagnostic features that differentiate neoplastic plexopathies from radiation-induced plexopathies. Neurolymphomatosis, in which malignant lymphocytes invade the cranial nerves, nerve roots, brachial and lumbosacral plexuses, and peripheral nerves, is a rare manifestation of lymphoma and leukemia. Diagnoses of neurolymphomatosis are often missed or delayed given its varied presentations, resulting in poorer outcomes. Thus this disease will also be discussed in depth.