Paraneoplastic vs. non-paraneoplastic anti-Hu associated dysmotility: a case series and literature review

Objectives This work aimed to report the demographic and clinical characteristics of two new cases with non-paraneoplastic anti-Hu-associated gut motility impairment, and perform a thorough revision covering anti-Hu-associated paraneoplastic (PGID) and non-paraneoplastic (nPGID) gastrointestinal dysmotility. Background Several case series have clearly established a relationship between certain type of cancers, the development of circulating anti-Hu antibodies, and the concomitant usually severe gastrointestinal dysmotility; in contrast, a few studies focused on anti-Hu-associated nPGID. Methods We searched for studies regarding anti-Hu-associated gastrointestinal manifestations and extracted data concerning clinical characteristics of patients, including specific demographic, oncological, neurological, gastrointestinal, histological, and treatment response features. Results Forty-nine articles with a total of 59 cases of anti-Hu-associated gastrointestinal dysmotility were analyzed. The patients' age at symptom onset significantly differed between PGID and nPGID (median 61 vs 31 years, p < 0.001). Most cancers (95%) in PGID were detected within 24 months from the beginning of gastrointestinal symptoms. The impairment of gastrointestinal motility was generalized (i.e., involving the whole gut) in 59.3% of patients, with no significant differences between PGID vs nPGID group. nPGID patients showed a better response to immunomodulatory/immunosuppressive treatment and a longer life expectancy. Conclusions Anti-Hu-associated gastrointestinal dysmotility covers a wide clinical spectrum. Patients with otherwise unexplained gastrointestinal dysmotility, especially when associated with other neurological symptoms, should be tested for anti-Hu antibodies regardless age of onset and disease duration. Compared to PGID, nPGID occurs in younger patients with a long duration of disease.