Motor neuron disease as a treatment responsive paraneoplastic neurological syndrome in patient with small cell lung cancer, anti-Hu antibodies and limbic encephalitis

Unexpected postmortem diagnoses in cases of clinically diagnosed amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a motor neuron disease that is clinically and pathologically characterized by impairment of the upper and lower motor neurons. The clinical diagnosis of ALS is not always straightforward because of the lack of specific biomarkers and clinical heterogeneity. This review presents the clinical and pathological findings of four autopsied cases that had been diagnosed with ALS before death. These cases had demonstrated definite and progressive motor neuron signs and symptoms, whereas postmortem assessment revealed miscellaneous disorders, including fungal infection, paraneoplastic syndrome, and amyloidosis. Importantly, nonmotor neuron signs and symptoms, including seizures, extra-pyramidal signs, ocular movement disorders, sensory disturbance, and dysautonomia, had also been documented during the disease course of the cases in the present study. The ALS-unlike symptoms were indicative of the "true" diagnosis in each case when those symptoms were isolated from motor neuron signs/symptoms.

Amyotrophic lateral sclerosis with coexisting cancer: a single-center study

This study investigated the occurrence of malignancy in a cohort of patients with amyotrophic lateral sclerosis (ALS). Forty-three consecutive ALS patients (mean age 61.3 years, 31 men/12 women) admitted between 2015 and 2019 were enrolled. Clinical, electrophysiologic and outcome features that differentiate cancer-associated ALS from classical ALS were investigated. ALS was associated with cancer in 5 (11.6%) patients. Two patients were diagnosed with non-small cell lung, one with endometrium, one with prostate and one with laryngeal carcinoma. One another patient was diagnosed with monoclonal gammopathy of unknown significance, but she did not develop cancer within 12-month follow-up duration. Two patients had a previous diagnosis of cancer before the diagnosis of ALS. In the remaining 3 patients, cancer was diagnosed at the same time or after the onset of ALS. There was no significant difference with respect to mean age of onset, sex, disease duration, clinical and electrophysiological features and outcome between patients with and without malignancy. None of the patients with cancer survived more than two years after the onset of ALS except one who was diagnosed with flail-leg syndrome before the diagnosis of non-small cell lung carcinoma. ALS is not accepted as a classical paraneoplastic neurological syndrome. Although the association of ALS and cancer seems coincidental, a careful investigation for an underlying cancer is important in patients with ALS. In our patient group with cancer-associated ALS, no distinguishing features were identified.

A paraneoplastic syndrome misdiagnosed as ALS: What are the red flags? A case report and review of the literature

Background Paraneoplastic motor neuron disease (PMND) is a rare, non-classical form of paraneoplastic neurological syndrome (PNS). Anti-Hu and anti-CV2/CRMP5 PNS are mostly associated with small-cell lung cancer (SCLC) and consist of highly variable clinical syndromes, including sensory neuronopathy, cerebellar ataxia and/or limbic encephalitis. However, substantial motor impairment is uncommon, particularly when no sensory dysfunction co-exists. Case A 72-year-old man with a recent diagnosis of amyotrophic lateral sclerosis (ALS) was referred to our department of neurology for evaluation. The patient sub-acutely developed progressive neurological dysfunction including erectile dysfunction, behavioral changes, limb weakness, dysphagia, anorexia, as well as worsening stridor that necessitated tracheostomy due to bilateral vocal cord paralysis (BVCP). Neurological examination revealed motor weakness of upper and lower motor neuron origin with autonomic and cognitive dysfunction. Cerebrospinal fluid (CSF) analysis demonstrated pleocytosis, elevated protein, presence of oligoclonal bands (OCB), and neuronal antibody testing was positive for anti-Hu and anti-CV2/CRMP5. Based on these findings a diagnosis of a PNS was made. Evaluation for malignancy was negative, and immunosuppressive/immunomodulatory treatment was initiated but had little effect during fifteen months of follow-up. Conclusions Although PMND is very rare, in an atypical presentation, especially with features that are not usually present in ALS such as autonomic dysfunction, sensory disturbance or cognitive decline, this etiology should be in the differential diagnosis.

Dorsal cauda equina nerve root enhancement on magnetic resonance imaging due to ANNA-1-associated paraneoplastic polyneuropathy

A 69-year-old female presented with subacute onset ascending weakness and paraesthesias. She was initially diagnosed with Guillain-Barré syndrome (GBS) based on her clinical presentation and cerebrospinal fluid (CSF) analysis showing albuminocytological dissociation. However, she was later found to have anti-neuronal nuclear antibody 1 (ANNA-1/anti-Hu)-positive CSF and was subsequently diagnosed with small-cell lung cancer. Her neurological symptoms were ultimately attributed to ANNA-1/anti-Hu-associated paraneoplastic polyneuropathy. During the course of her evaluation, she had magnetic resonance imaging findings of dorsal predominant cauda equina nerve root enhancement, which has not been previously described. The only previously reported case of cauda equina enhancement due to ANNA-1-associated polyneuropathy described ventral predominant findings. The distinction between ventral and dorsal enhancement is important, since it suggests that different patterns of nerve root involvement may be associated with this paraneoplastic syndrome. Therefore, ANNA-1-associated paraneoplastic inflammatory polyneuropathy can be considered in the differential diagnosis of cauda equina nerve root enhancement with ventral and/or dorsal predominance. This can potentially be helpful in differentiating ANNA-1 polyneuropathy from GBS, which classically has ventral predominant enhancement.