Ileocecal Paracoccidioidomycosis Presenting as a Pseudotumoral Lesion in a Pediatric Patient: A Histopathological Diagnostic Challenge.

Ileocecal pseudotumoral lesions in pediatric patients pose a significant diagnostic challenge, particularly in endemic regions where infectious and neoplastic conditions overlap. Gastrointestinal paracoccidioidomycosis (PCM) is rare and may closely mimic intestinal tuberculosis or malignancy, leading to potential misdiagnosis. We report a 14-year-old girl presenting with constitutional symptoms and imaging findings of ileocecal wall thickening with mesenteric lymphadenopathy. Endoscopy revealed ulceroinfiltrative lesions suggestive of neoplasia. Histopathological evaluation demonstrated granulomatous inflammation with multinucleated giant cells and abundant yeast forms. A critical diagnostic pitfall arose during special staining: Grocott-Gomori methenamine silver staining produced a pseudohalo around the fungal elements due to cytoplasmic retraction and optical clearing of the thick fungal cell wall, mimicking the capsular appearance of Cryptococcus spp. Periodic acid-Schiff staining resolved this ambiguity by clearly demonstrating the characteristic multibudding "pilot wheel" morphology of Paracoccidioides spp., and mucicarmine negativity definitively excluded a polysaccharide capsule, ruling out cryptococcosis. This example underscores the interpretive value of a sequential histochemical staining approach in distinguishing morphologically overlapping fungi, and highlights PCM as an essential differential diagnosis in ileocecal masses within endemic settings, particularly in pediatric populations.