Adenocarcinoma pulmonar, dermatomiosite e síndrome miastênica de Lambert-Eaton: uma rara associação

Abstract

The incidence of lung neoplasms is increasing in Brazil and in the world, probably as a result of the increase in smoking. Due to the greater number of cases, atypical presentations appear. We report the case of a 66-year-old hypertensive male smoker who presented progressive proximal muscular weakness and, in two months, evolved to dysphagia, dysphonia, and V-shaped skin lesions on the chest. A chest X-ray showed a spiculated pulmonary nodule in the right upper lobe. The biochemical analysis revealed elevated creatine kinase levels. After complementary tests and biopsies, the patient underwent right upper lobectomy. Histopathology showed a moderately differentiated adenocarcinoma. The overall analysis of the case and a review of the literature allow us to suggest that the clinical profile of the patient was a result of an overlap of two paraneoplastic syndromes (dermatomyositis and Lambert-Eaton myasthenic syndrome) secondary to lung adenocarcinoma.Keywords: Lung neoplasms; Paraneoplastic syndromes; Dermatomyositis; Lambert-Eaton myasthenic syndrome; Adenocarcinoma. ResumoA incidência das neoplasias pulmonares vem aumentando no Brasil e no mundo, provavelmente como resultado do aumento do tabagismo. Com o maior número de casos, surgem as apresentações atípicas. Relatamos o caso de um paciente do sexo masculino, 66 anos, tabagista e hipertenso, que apresentava quadro de fraqueza muscular proximal progressiva e, em dois meses, evoluiu com disfagia para alimentos sólidos, disfonia e lesões cutâneas em forma de "V" no tórax. O radiograma de tórax mostrou um nódulo pulmonar espiculado no lobo superior direito. A análise bioquímica revelou aumento da creatinoquinase. Após exames complementares e biópsias, o paciente foi submetido à lobectomia superior direita. A histopatologia evidenciou um adenocarcinoma moderadamente diferenciado. A análise global do caso e a revisão de literatura permitem sugerir que o quadro clínico do paciente era resultante da sobreposição de duas síndromes paraneoplásicas, a saber, a dermatomiosite e a síndrome miastênica de Lambert-Eaton, secundárias a um adenocarcinoma pulmonar.

Dermatomyositis as the first manifestation of a lung tumor

“…Atrophy reflects the characteristic perifascicular endofascicular hypoperfusion. 1,2,9,11 In these cases, dermatomyositis improves with cancer treatment and there is a recurrence of muscle weakness when the tumor relapses, thus suggesting a paraneoplastic nature. 7 Autoantibodies against nuclear antigens (ANA, anti-dsDNA, etc.)…”

Lung adenocarcinoma with Lambert–Eaton myasthenic syndrome indicated by voltage-gated calcium channel: a case report

“…A PubMed literature search (keywords, ‘Lambert-Eaton Myasthenic Syndrome’ and ‘lung adenocarcinoma’) found only two publications in the English literature [7,10]. In Japan, although five cases have been reported to date, there are only two reports of LEMS associated with lung adenocarcinoma in Japanese research with an English abstract [11,12].…”

Adenocarcinoma of Lung Presenting as Lambert-Eaton Myasthenic Syndrome

“…A PubMed and Google Scholar literature search discovered only 5 published cases (Table 1) in the literature (English), reporting LEMS associated with pulmonary adenocarcinoma. 1-5 In this article, we report a rare case of LEMS associated with adenocarcinoma of the lung.…”