Histoplasmosis caused by Histoplasma capsulatum var. duboisii (H. duboisii) is a profound opportunistic mycosis, endemic in Africa. The precise epidemiology of H. duboisii infection and its pathogenesis remains poorly understood. Histoplasmosis has a wide range of clinical presentations that depend primarily on three factors: fungal load, virulence and Histoplasma strain, and host immune status .
More commonly involving organs such as the liver, spleen, bone marrow and skin . Peritonitis associated with H. capsulatum is extremely rare, with few cases reported in the literature. Risk factors for developing fungal peritonitis include previous antibiotic use, immunosuppression status, environmental exposure, intra-abdominal surgery, and extraperitoneal spread of fungal infection . We report the first observation in Mauritania of an isolated peritoneal localization of H. duboisii histoplasmosis in an immunocompetent patient.
2. Patient and Observation
The 60-year-old male patient had emigrated from Mauritania to Guinea Bissau, Congo and Senegal; he had a history of pulmonary tuberculosis, treated and declared cured, and partial epileptic seizures treated with carbamazepine.
The clinical examination noted abdominal pain giving the impression of heaviness. The remainder of the clinical examination, particularly pulmonary, neurological, lymph node and locomotor, was unremarkable. Abdominal computed tomography (CT) (Figure 1), sagittal section revealed a large mass with a large intraperitoneal fluid component with a finely calcified wall in places, located opposite the 3rd, 4th, 5th lumbar vertebrae, and plunging in the pelvis by its lower pole above the bladder, measuring 157 × 100 mm. Anatomopathological examination of the operative parts (Figure 2) revealed Histoplasma capsulatum var. duboisii stained with eosin hematoxylin at ×400 magnification shows a rounded or oval, corresponding to a bulky nucleus surrounded by a pseudo capsule producing a clear halo appearance (Figure 3(a)). Histoplasmosis capsulatum var. duboisii at ×400 magnification showing the yeast-like appearance
Figure 1. Abdominal CT scan sagittal section revealed a large mass with a large intraperitoneal fluid component with a finely calcified wall in places, located opposite the 3rd, 4th, 5th lumbar vertebrae, and plunging in the pelvis by its lower pole above the bladder, measuring 157 × 100 mm.
Figure 2. Macroscopic view of operating parts.
Figure 3. (a) Histoplasma capsulatum var. duboisii stained with eosin hematoxylin at ×400 magnification shows rounded or oval, corresponding to a bulky nucleus surrounded by a pseudo capsule producing a clear halo appearance. (b) Histoplasmosis capsulatum var. duboisii at ×400 magnification showing the yeast-like appearance with double contour. (c) Epitheloid and gigantocellular granuloma, without necrosis, stained with eosin hematoxylin at 100× magnification. (d) Multinucleated giant cells mixed with yeast-like aspects dissociating fibrous tissue stained with hematoxylin-eosin at ×400 magnification.
with double contour (Figure 3(b)). Epitheloid and gigantocellular granuloma, without necrosis, stained with eosin hematoxylin at 100× magnification (Figure 3(c)). Multinucleated giant cells mixed with yeast-like aspects dissociating fibrous tissue stained with hematoxylin-eosin at ×400 magnification (Figure 3(d)). Staining by Periodic Acid Schiff (P.A.S) stains these forms purple-pink, with the pseudo-capsule visible (Figure 4(a), Figure 4(b)). Gomori-Grocott silver impregnation at high magnification ×400 shows the wall stained in black of the yeasts in intrahistiocytic position dispersed in the necrosis (Figure 5(a)). And the black-colored wall of the yeasts (Figure 5(b)).
Figure 4. (a) Staining by P.A.S. (Periodic Acid Schiff) staining these forms in purple-pink, with the pseudo capsule visible. (b) Staining by P.A.S. (Periodic Acid Schiff) staining these forms in purple-pink, with the pseudo capsule visible.
Figure 5. (a) Gomori-Grocott silver impregnation at high magnification ×400, is the reference complementary stain, which shows the wall stained in black of the yeasts in intrahistiocytic position dispersed in the necrosis. (b) Gomori-Grocott silver print at high magnification ×400, which shows the black-colored wall of the yeasts.
The patient was operated on for the peritoneal mass, with simple postoperative treatment followed by treatment with itraconazole at a dosage of 400 mg/day for 14 days. The regression was favorable after 9 months of follow-up.
African histoplasmosis is a rare granulomatous infection first described by Catanei in 1945 . Caused by the dimorphic fungus Histoplasma capsulatum var. duboisii. This infection is most common in Central and West African countries. Numerous cases have been reported in Senegal , Mali , Ivory Coast . The case we are reporting is original, as it is the first description of this condition in Mauritania. However, this infection has been reported in neighboring countries. Its frequency increases proportionally with HIV infection . Our patient was immunocompetent, with a history of pulmonary tuberculosis, which contradicts the data in the literature . Histological examination of the operative specimen reveals a polymorphic granulomatous infiltrate, with multi-nucleated giant cells, within which we can distinguish multiple yeast-like bodies of large size, with thickened walls, and with a double positive contour for P.A.S and Gomori-Grocott stain characteristic of Histoplasma duboisii.
The mycological examination allows the visualization of ovoid-shaped yeasts, mainly intracellular. Classically, according to many authors, histopathological examination is a sensitive method that makes it possible to confirm the diagnosis in 87% of cases  . Treatment involves itraconazole; high doses of ketoconazole can, however, give good results.
Histoplasmosis is a rare condition in immunocompetent patients, but not exceptional. The clinician should think about this when considering any peritoneal mass in a patient who has stayed in Central and West Africa.
Contributions from the Authors
All the authors have marked when carrying out this work. All authors also declare that they have read and approved the final version of the manuscript.
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