Paraneoplastic Cerebellar Degeneration and Lambert-Eaton Myasthenic Syndrome Associated with Neuroendocrine Carcinoma of the Oropharynx

Approach to gait disorders and orthotic management in adult onset neuromuscular diseases

In order to understand abnormal gait, this article will first review normal gait, discuss how neuromuscular diseases disturb gait patterns and review orthotic interventions. In normal gait, concentric contractions accelerate and eccentric contractions decelerate the limb. Neuromuscular gait disorders can be grouped into (1) proximal weakness, (2) distal weakness, (3) nonlength-dependent or generalized weakness, (4) asymmetric weakness, and (5) sensory disorders. Identification of gait disturbance type in neuromuscular diseases leads to the appropriate orthotic prescription since orthotic strategies are grouped into (1) proximal weakness, (2) distal weakness, and (3) sensory disturbances. Orthotics is not indicated in all types of gait disturbance. Weakness in proximal hip musculature can be managed with gait aids such as walkers. In contrast, distal muscle weakness can be managed with orthotics. Preservation of gait assists in maintenance of daily function and integration in society.

Human papillomavirus status and prognosis of oropharyngeal high-grade neuroendocrine carcinoma

BACKGROUND

The prognostic impact of human papillomavirus (HPV) infection or smoking on oropharyngeal high-grade neuroendocrine carcinoma (HG-NEC) is not established.

METHODS

Retrospective study with patients with oropharyngeal HG-NEC seen at MD Anderson Cancer Center from 1997 to 2020, and previously reported patients with oropharyngeal HG-NEC and known p16 and HPV status from the literature review. Survival was estimated with the Kaplan-Meier method, and survival differences assessed with the log-rank test and Cox proportional hazards models.

RESULTS

Thirty patients were included; most had a heavy (≥10 pack-years) smoking history (52%), locoregional disease (stage III-IVB; 77%), and p16-positive tumor (92%). HPV was positive in 65% of tested samples (15/23). Of 24 patients treated with curative intent, the objective response rates was 90% (9/10) and 81% (17/21), respectively, for induction chemotherapy and definitive radiotherapy. During follow-up, 54% (13/24) recurred, mostly (11/13) at distant sites. Median overall survival (OS) was 46 months (95% CI, 14.3 - NA). OS was not associated with HPV status (HR 0.73, P = 0.6) or smoking (HR 1.16, P = 0.8). Among 63 patients with known HPV status after the literature review (19 HPV- and 44 HPV + ), HPV status remained unassociated with OS (P = 0.92).

CONCLUSIONS

This is the largest retrospective cohort of oropharyngeal HG-NEC. Distant recurrence rate after curative treatment was high, suggesting that multimodality treatment including systemic therapy may benefit patients with locally advanced disease. HPV infection did not affect survival outcomes, therefore should not lead to therapy de-intensification for this histology.

Paraneoplastic motor disorders

Paraneoplastic neurological disorders (PNDs) are heterogeneous clinicopathologic syndromes that occur throughout the neuraxis resulting from damage to organs or tissues remote from the site of a malignant neoplasm or its metastases. The discordance between severe neurological disability and even an indolent malignancy suggests an underlying neuroimmunologic host immune response that inflicts nervous tissue damage while inhibiting malignant tumor growth. Motor system involvement, like other symptoms and signs, is associated with focal or diffuse involvement of the brain, spinal cord, peripheral nerve, neuromuscular junction or muscle, alone or in combination due to an underlying neuroimmune and neuroinflammatory process targeting neural-specific antigens. Unrecognized and therefore untreated, PNDs are often lethal making early detection and aggressive treatment of paramount importance. While the combination of clinical symptoms and signs, and analysis of detailed body and neuroimaging, clinical neurophysiology and electrodiagnostic studies, and tumor and nervous system tissue biopsies are all vitally important, the certain diagnosis of a PND rests with the discovery of a corresponding neural-specific paraneoplastic autoantibody in the blood and/or spinal cerebrospinal fluid.

Systematic review of neuroendocrine carcinomas of the oropharynx

Data describing features and management of oropharyngeal neuroendocrine carcinomas (NEC) remain sparse. A systematic review was performed. Patients were stratified by treatment modality and examined for disease progression and survival outcomes. Ninety-four patients from 50 publications were included. Average age at diagnosis was 59.7 years (range 14-83). 73.4% were male. Most studies did not document HPV status. Forty patients (85.1%) were p16 positive, and 34 (85.0%) were HPV-ISH positive. Overall survival was 75.4% at 1 year, and 40.0% at 2 years. Of patients with locoregional disease, 33.8% developed distant metastasis. 12.5% of patients developed locoregional recurrence. Patients who developed distant metastases had worse overall survival (p = 0.0004). No significant difference was found between treatment modalities. Human papilloma virus may be associated with oropharyngeal NEC. Current treatments provide locoregional control, but distant metastases are common and confer low overall survival.

Acute-onset paraneoplastic cerebellar degeneration secondary to neuroendocrine carcinoma with atypical prognosis: a case report

Paraneoplastic cerebellar degeneration (PCD) is a neurological syndrome that is likely caused by tumor-induced autoimmunity against the cerebellum. Neuroendocrine carcinoma (NEC) is a type of neoplasm with high-grade malignant histology and biological behavior. The prognosis for both PCD and NEC is typically poor. We report a case of PCD secondary to metastatic NEC in the lymph nodes, with an unknown primary origin. The case presented acute cerebellar manifestations with typical neuroimaging findings, but with atypical prognosis after lymph node dissection. Neurological symptoms can provide clues to potential tumors, and early antitumor treatment may have contributed to the positive prognosis of PCD secondary to NEC in the present case.

Human Papillomavirus-Associated Oropharyngeal High-Grade Neuroendocrine Carcinoma in an Adolescent: Case Report and Review of Literature

Oropharyngeal small cell carcinomas (OPSmCC) are rare with only few case reports and case series published in the literature. More recently, an association of these tumors with human papillomavirus (HPV) infection has been detected. However, unlike oropharyngeal squamous cell carcinomas which have a better outcome when associated with HPV, OPSmCC exhibit an aggressive behavior. In this article, we report a case of tonsillar carcinoma arising in a 14-year-old boy that was associated with HPV infection. The tumor exhibited morphologic features of small cell carcinoma with no overt squamous differentiation. Yet, by immunohistochemistry, it showed diffuse and strong co-expression of both squamous and neuroendocrine markers. In addition, we present the clinicopathologic features of all the cases of OPSmCC reported in the literature for which p16 and/or HPV testing have been done.

Paraneoplastic movement disorders: phenomenology, diagnosis, and treatment

Paraneoplastic syndromes include, by definition, any symptomatic and non-metastatic condition associated with a neoplasm. Paraneoplastic movement disorders are a heterogeneous group of syndromes encompassing both hyperkinetic and hypokinetic conditions, characterized by acute/sub-acute onset, rapidly progressive evolution, and multifocal localizations with several overlapping features. These movement disorders are immune-mediated, as shown by the rapid onset and by the presence of antineuronal antibodies in biological samples of patients, fundamental for the diagnosis. Antineuronal antibodies could be targeted against intracellular or neuronal surface antigens. Paraneoplastic movement disorders associated with anti-neuronal surface antigens antibodies respond more frequently to immunotherapy. The underlying tumors may be different, according to the clinical presentation, age, and gender of patients. Our search considered articles involving human subjects indexed in PubMed. Abstracts were independently reviewed for eligibility criteria by one author and validated by at least one additional author. In this review, we sought to critically reappraise the clinical features and the pathophysiological mechanisms of paraneoplastic movement disorders, focusing on diagnostic and therapeutic strategies. Our main aim is to make clinicians aware of paraneoplastic movement disorders, and to provide assistance in the early diagnosis and management of these rare but life-threatening conditions.