Shelly, Shahar

ABSTRACT Background Myasthenia gravis (MG) is strongly associated with thymic tumors, but whether it is also associated with extrathymic cancers is debatable or whether MG can be considered a paraneoplastic disorder for extrathymic cancers. Methods This is a retrospective analysis of the MG cohort for 23 years' time (January 2000 to May 2023), extracting cancer rates with clinical, electrophysiological, and biochemical cancer associations and the effect of chronic medications. Results We identified 436 patients with MG and 3924 controls. The median age at symptom onset was 64 (5–93 years) for males and 54 (1–87 years) for females. MG symptoms at onset were recorded as ocular (60%), strictly bulbar (10%), or generalized (23%). Extrathymic cancer was found in 32% of MG patients. In 3%, thymic and extrathymic cancers co‐occurred. Compared to controls, neurology (12.2%, 159/1308), internal medicine (24.4%, 319/1308), or rheumatology (12%, 157/1308), MG patients had significantly higher rates of extrathymic cancers ( p < 0.001). Compared to the rheumatology group, the cancer relative risk of 2.97, CI = 2.5–3.4. Furthermore, the prevalence of extrathymic cancers was significantly increased within the paraneoplastic time window, defined as ±5 years from cancer diagnosis to myasthenia onset ( p < 0.01). Conclusion MG was significantly associated with an increased risk of extrathymic cancers, particularly within the paraneoplastic time window. These findings suggest that MG might potentially behave as a paraneoplastic disorder.

Abstract Background: Vasculitic neuropathies usually present acutely to subacutely, with an asymmetric pattern, involving multiple peripheral nerve territories. Drug-induced vasculitis is an often overlooked etiology of vasculitic neuropathy. Methods: We present the first reported case of nitrofurantoin-associated and an illustrative case of minocycline-associated vasculitic neuropathy, with a review of the literature. Results: The first patient is a 60-year-old woman who developed axonal sensorimotor peripheral neuropathy after nitrofurantoin use, with a superficial radial nerve biopsy confirming vasculitis. The second patient is a 23-year-old woman, with a history of acne vulgaris treated with minocycline, who presented with a subacute right common peroneal mononeuropathy followed by a left deep peroneal mononeuropathy, with elevated antinuclear, perinuclear-antineutrophil cytoplasmic, and myleoperoxidase antibodies, and MPO titers, and a sural nerve biopsy showing large arteriole vasculitis. Finally, we provide a comprehensive review of previously published cases. Conclusions: Medications should be considered as a trigger for medication-induced vasculitic neuropathy. Accurate diagnosis would ensure timely treatment.