Atypical Localization of Leishmaniasis in an Intestinal Polyp

Abstract

Unusual localizations of visceral leishmaniasis are described in patients with AIDS and in geriatric immunocompetent subjects [1–3]. We present a case report of leishmaniasis in an HIV-negative elderly patient with large bowel Leishmania polyp. An HIV-negative 74-year-old man with a history of well-controlled diabetes and diverticulitis was hospitalized because of a clinical presentation characterized by debilitating asthenia, 12-kg-weight loss in 2 months, fever, and gastrointestinal symptoms such as diarrhoea and abdominal pain. Physical examination showed cutaneous pallor, hepato-splenomegaly, and a temperature of 39 � C. Laboratory findings were as follows: a widespread pancytopenia (hemoglobin 8.1 g/dl, white blood cell count 2.9 · 10 9 cells/l, platelets 81 · 10 9 cells/l), an erythrocyte sedimentation rate of 84, hepatitis markers negative, abnormal liver function (total protein 5.9 g/dl; albumin 2.3 g/dl) and normal coagulation. Bone marrow biopsy was performed but it was not diagnostic. Indeed, it revealed a reduced presence of maturing cells (less than 50%); the rare hollows, seat of trilinear hematopoiesis, presented aspects of dyserythropoiesis but did not allow a specific diagnostic judgement. Since the patient referred persistent digestive tract symptoms such as diarrhoea associated with severe abdominal pain, a total body CT scan was performed. It showed only hepatosplenomegaly. An endoscopy examination of digestive tract was performed in order to reach a correct diagnosis. Many diverticula and a peduncolate digital polyp in correspondence of the descendent colon were found and biopsies were taken. The histological examination of the polyp showed: hyperplasia of mucous membrane of large intestine, many aggregates of histiocytes in the lamina propria containing in their cytoplasm spheroid micro-organism, GIEMSA positive, with suggestive morphology for Leishmania spp. Other organisms (e.g., histoplasma) mimicking Leishmania bodies on histology were excluded. On the basis of this result, we repeated a bone-marrow biopsy, which after a careful reading, confirmed the presence of Leishmania amastigotes. Serology confirmed the presence of a visceral leishmaniasis, with a significant anti-Leishmania antibody titre (> 1:2,560) detected by indirect immunofluorescence. The patient received liposomial amphotericin B therapy (AmBisome, Nextar, San Dimas, CA, USA) at a dosage of 3 mg/kg on days 1–5 and 10. At the end of treatment, there was a complete resolution of systemic symptoms and his spleen size was normal. Furthermore, the patient had another endoscopic examination of the digestive tracts with complete resection of the polyp; histological examination of removed tissues did not show the presence of Leishmania. During the follow-up we observed a progressive decline of antileishmanial antibody titres, with values of 1:320 and 1:40 after 3 and 12 months, respectively. Intestinal localization of Leishmania has been re