Neoplastic and non-neoplastic lesions in the upper digestive tract associated with the ingestion of Pteridium esculentum subsp. arachnoideum by 3 water buffalo in Brazil

Upper digestive tract neoplasms associated with ingestion of Pteridium spp. (bracken fern) have been documented in cattle but not in buffalo. Here, we describe upper digestive tract lesions associated with the ingestion of P. esculentum subsp. arachnoideum in 3 water buffalo (Bubalus bubalis) in Brazil. Gross inspection revealed proliferative and ulcerative lesions in the mucosa of the base of the tongue, oropharynx, and esophagus in all 3 cases. Proliferative lesions were well-demarcated, white-to-brown, exophytic nodules on the lingual and oropharyngeal mucosa (papillomas, cases 1–3); a well-demarcated, white nodular fibroma in the distal esophageal submucosa (case 1); and locally infiltrative areas of mucosal thickening with ulceration and dark red-to-brown areas of hemorrhage in the base of the tongue and oropharynx (squamous cell carcinomas [SCCs], cases 1–3). Histologically, non-neoplastic lesions were irregular (cases 2, 3) or pseudocarcinomatous (case 1) mucosal hyperplasia with parakeratosis (cases 1–3) and dysplasia (cases 1, 2) in the base of the tongue, oropharynx, and esophagus. Neoplastic lesions were papillomas affecting the base of the tongue, oropharynx, and esophagus (cases 1–3); a submucosal distal esophageal fibroma (case 1); and SCCs affecting the base of the tongue and oropharynx (cases 1–3). Mucosal ulceration was associated with the SCCs in all cases. Inflammation was lymphoplasmacytic. Esophageal vascular myxomatous degeneration or proliferation with fibrosis were present. The diagnoses of Pteridium-associated disease were based on the epidemiologic and pathologic findings, which were identical to those observed in cattle.