Proposed histological progression of the Spirocerca lupi-induced oesophageal lesion in dogs

Abstract

This study aims to outline the histological progression of the Spirocerca lupi nodule from infection to neoplastic transformation. Sixty-two spirocercosis-induced nodules, 42 nonneoplastic and 20 neoplastic, were stained with HE. Ten non-overlapping high power fields per nodule were examined and non-neoplastic and neoplastic nodules were compared. Inflammation was scored 0-3 and revealed a score of 1.91 ± 0.52 in the non-neoplastic and 0.97 ± 0.5 in the neoplastic cases (p < 0.01). In most non-neoplastic cases the inflammatory infiltrate was lymphoplasmacytic and in the neoplastic cases neutrophils predominated. Necrosis was scored 0-3 and revealed a score of 0.88 ± 0.41 in the non-neoplastic and 1.47 ± 0.5 in the neoplastic cases (p < 0.01). The average number of mitoses over 10 high power fields per nodule was 1.31 ± 1.55 in the non-neoplastic compared to 42.85 ± 30.79 in the neoplastic cases (p < 0.01).The average number of multinucleated giant cells over 10 high power fields per nodule was 0.9 ± 1.45 in the non-neoplastic compared to 13.9 ± 14.66 in the neoplastic cases (p < 0.01). In the non-neoplastic cases, collagen, immature fibroblasts and fibroblast activation (excessively plump euchromatic nuclei with single or multiple prominent nucleoli) were scored 0-3 and a combined score, fibroblasts + activation score − collagen was calculated. The non-neoplastic cases were divided into a combined score of ≤1 (n = 15) or >1 (n = 27). The 2 groups had similar scores for inflammation and necrosis, but were significantly different (p < 0.01) in mitotic index (0.26 ± 0.46 vs. 1.89 ± 1.65) and number of multinucleated cells (0 vs. 1.4 ± 1.6). These results indicate 2 stages in the non-neoplastic nodules: early inflammation, characterized by fibrocytes and abundant collagen, and a pre-neoplastic stage, characterized by activated fibroblasts and reduced collagen.

Evaluation of Hemostatic Abnormalities in Canine Spirocercosis and Its Association with Systemic Inflammation

“…The significant difference in CRP concentration between neoplastic and non‐neoplastic groups agrees with previous reports on spirocercosis 9. When the CRP concentration was compared between the non‐neoplastic and control groups, no significant difference was found, which is surprising considering the inflammation that is observed histologically in the non‐neoplastic nodules 1, 34. The reason for this finding is unclear and is contrary to previous reports on CRP concentration in spirocercosis 9.…”

“…Spirocerca lupi ( S. lupi ) is a canine nematode infesting the esophageal wall resulting in the formation of fibro‐inflammatory nodules 1. The nodules may undergo neoplastic transformation into osteosarcoma (60–85% of neoplastic cases), fibrosarcoma, or anaplastic sarcoma in up to 26% of dogs 1, 2, 3.…”

Serum C‐Reactive Protein Concentration in Benign and Malignant Canine Spirocercosis

“…Severe inflammation has been described in the histopathology of benign and malignant nodules in canine spirocercosis. 5 The inflammatory reaction in the benign nodule is predominantly lymphoplasmacytic, but pockets of neutrophilic infiltrates around the worms, eggs, and migratory tracts are very common. The malignant nodules have a predominantly neutrophilic infiltrate that is associated with areas of ulceration and necrosis.…”

“…The malignant nodules have a predominantly neutrophilic infiltrate that is associated with areas of ulceration and necrosis. 5 The neutrophilic infiltration seen on histopathology in the malignant nodules is an indicator of an active inflammatory reaction. The presence of inflammation, especially neutrophilic response in both the benign and malignant nodules, possibly explains the similarities between the serum CRP concentrations in the dogs with benign and malignant spirocercosis at presentation.…”

“…4 In the esophagus, an inflammatory fibrous tissue nodule is formed around the worms. 5 The nodule may be transformed into an osteosarcoma, fibrosarcoma, or anaplastic sarcoma. 4 Benign spirocercosis can be successfully treated with doramectin a at 400 mg/kg SC every 2 weeks whereas malignant spirocercosis requires surgical excision of the esophageal sarcoma, with or without chemotherapy, and the long-term prognosis is poor.…”