Excretion of Ascaris lumbricoides following reduced‐intensity allogeneic hematopoietic stem cell transplantation and consecutive treatment with mebendazole

Here, we present the unique case of a 51‐year‐old German patient with multiple myeloma excreting Ascaris lumbricoides in his stool five weeks after allogeneic hematopoietic stem cell transplantation. Stool analysis remained negative for the presence of eggs, and there was no eosinophilia in the peripheral blood at any time around stem cell transplantation. The patient was commenced on a three‐day treatment with mebendazole, which was well tolerated. No serious interactions with the concomitant post‐transplant medication or negative effects on the hematopoiesis were observed, and the myeloma still is in complete remission. To our knowledge, this is the first report on excretion of A lumbricoides in the context of allogeneic stem cell transplantation. The case is remarkable with view to the fact that the parasite has supposedly survived all courses of myeloma treatment including autologous and allogeneic conditioning. Parasitosis with A lumbricoides has a worldwide prevalence of about a billion and is extremely rare in northern Europe. Possibly the patient got infected during a trip to Egypt years before multiple myeloma was diagnosed.