Refractory feline sporotrichosis: a comparative analysis on the clinical, histopathological, and cytopathological aspects

ABSTRACT: Sporotrichosis is a chronic fungal infection caused by Sporothrix species. The occurrence of cases that are resistant to long-term treatment, especially in the nasal planum of cats, emphasizes the importance of studying its pathogenesis. The purpose of this study was to analyze and compare the inflammatory process of cutaneous lesions of feline refractory sporotrichosis to clinical aspects through cytopathological and histopathological examination. Moreover, the study included 13 cats with cutaneous lesions that had been resistant to itraconazole treatment for more than a year. Cutaneous lesions samples were collected for cytopathological, histopathological, and fungal culture analyses. Tissue fragments were processed and stained with hematoxylin-eosin (HE) and Grocott methenamine silver (GMS). Further, two clinical presentations had the highest occurrence: the localized cutaneous form in animals with good general condition and stable disease (n=9, 69.2%) and the disseminated cutaneous form in cats with poor general condition (n=4, 30.8%). In cats with refractory sporotrichosis, the nasal planum (84.6%) was the most common location of lesions. In the cytopathological study, cats with fewer than two lesions and in good general condition (n=9, 69.2%) showed absence or mild yeast intensity (up to 5 yeasts per field), lower intensity of macrophages and neutrophils, and higher intensity of epithelioid cells, lymphocytes, plasma cells, and eosinophils. On the other hand, (n=4, 30.8%) of the cats with disseminated sporotrichosis and a poor general condition had a marked intensity of yeasts, which were mostly phagocytosed by an increased number of macrophages and neutrophils. Of those animals with good general condition, the majority (n=6, 66.7%) had higher eosinophil intensity. In histopathology, malformed suppurative granuloma was the predominant type (n=9, 69.2%) in feline sporotrichosis lesions, followed by well-formed granulomas (n=4, 30.8%). Malformed granulomas showed mild to moderate fungal intensity (55.6%) in animals with good general condition and localized lesions while marked fungal intensity (44.4%) in cats with the disseminated form of the disease and poor general condition. Well-formed granulomas (n=4, 30.7%) had mild to moderate intensity of fungal load, and 75% of the animals with this type of granuloma had only one lesion and were in good general condition. Long-term itraconazole treatment in these cats with refractory sporotrichosis can keep the infection under control and localized lesions stable; however, fungus reactivation can occur, resulting in an exuberant and inefficient immune response.

RESUMO: A esporotricose é uma infecção fúngica crônica causada por espécies do gênero Sporothrix. A ocorrência de casos refratários ao tratamento de longo prazo, especialmente na região nasal de gatos, alerta para a importância do estudo de sua patogênese. Este estudo teve como objetivo analisar o processo inflamatório das lesões cutâneas de esporotricose felina refratária ao tratamento, por meio de exames citopatológico e histopalógico, e comparar com aspectos clínicos. Treze gatos com lesões cutâneas refratárias ao tratamento com Itraconazol por mais de um ano foram incluídos no estudo. Amostras de lesões cutâneas foram coletadas para análises citopatológicas, histopatológicas e cultura fúngica. Fragmentos de tecidos foram processados e corados pela hematoxilina-eosina (HE) e Prata Metenamina de Grocott (GMS). Duas apresentações clínicas tiveram maior ocorrência: a forma localizada cutânea em animais com bom estado geral e doença estável (n=9, 69,2%); e a forma disseminada cutânea em gatos com estado geral ruim (n=4, 30,8%). A região nasal (84,6%) foi a localização mais frequente das lesões nos gatos com esporotricose refratária ao tratamento. No estudo citopatológico, felinos com menos de duas lesões, e em bom estado geral, (n=9, 69,2%) revelaram ausência ou leve intensidade de leveduras (até 5 leveduras por campo), menor intensidade de macrófagos e neutrófilos, e maior intensidade de células epitelióides, linfócitos, plasmócitos e eosinófilos. Enquanto, (n=4, 30,8%) dos felinos que apresentavam a forma disseminada da esporotricose associada a um estado geral ruim, revelaram acentuada intensidade de leveduras em sua maioria fagocitadas por acentuado número de macrófagos e neutrófilos. Dos animais com bom estado geral, a maioria (n=6, 66,7%) apresentava maior intensidade de eosinófilos. Na histopatologia, o granuloma supurativo mal formado foi o tipo predominante (n=9, 69,2%) nas lesões de esporotricose felina, e (n=4, 30,8%) foram de granulomas bem formados. Granulomas mal formados apresentaram leve a moderada intensidade fúngica (55,6%) nos animais com bom estado geral e lesões localizadas, e acentuada intensidade fúngica (44,4%) nos gatos com a forma disseminada da doença e estado geral ruim. Granulomas bem formados (n=4, 30,7%) apresentaram leve a moderada intensidade de carga fúngica, sendo 75% dos animais com esse tipo de granuloma com apenas uma lesão e bom estadogeral. O tratamento de longo prazo com itraconazol, nesses gatos com esporotricose refratária, pode manter a infecção controlada e lesões localizadas estáveis de forma temporária, contudo a reativação do fungo pode ocorrer levando a uma resposta imunológica exuberante e ineficiente.

Histologic evaluation of Ki-67 and cleaved caspase-3 expression in feline mammary carcinoma.

Objectives The purpose of this study was to evaluate histopathologic aspects of, and the expression of Ki-67 and cleaved caspase-3 in, feline mammary carcinoma (FMC). Methods Feline mammary tumors were surgically obtained by mastectomy from 30 female cats and were fixed with formalin and embedded in paraffin wax. Four-micron sections were stained with hematoxylin and eosin for histopathologic diagnosis. Ki-67 and cleaved caspase-3 were analyzed by immunohistochemistry. Results Samples were histologically confirmed as FMC. Positive immunostaining was observed in all cancer samples for both nuclear Ki-67 and cleaved caspase-3, with a mean positive staining percentage of 27.5% and 21.2%, respectively. No statistically significant correlations between Ki-67 and cleaved caspase-3 were observed within FMC. Conclusions and relevance A high proliferation index was found in feline mammary tumors. This is the first study evaluating cleaved caspase-3 expression in FMC.

Esophageal stricture caused by rib osteoma in a cat: case report.

CASE SUMMARY: A 6-year-old male domestic shorthair cat presented with frequent food regurgitation and dysphagia. Plain thoracic radiographs revealed a calcified mass overlying the topography of the mediastinum, as well as dilation of the cervical portion of the esophagus due to an accumulation of food. Endoscopic examination showed a severe extraluminal esophageal stricture at the mediastinum entrance. Surgery and a gastric tube were declined by the cat's owner, with palliative support preferred. However, 1 year later, the cat presented with severe cachexia, dysphagia, salivation, dehydration and inspiratory dyspnea. Thoracic computed tomography was performed to evaluate the possibility of surgical resection. A mass of bone density originating in the second left rib was observed. The mass did not appear to have invaded adjacent structures but marked compression of the mediastinal structures was observed. Surgical resection was performed and a prosthetic mesh was used to reconstruct the thoracic wall. Transient Horner's syndrome developed in the left eye postoperatively, and was resolved within 4 weeks. Histopathology revealed a benign osteoma. Thirty-two months after surgery, the cat was well and free of disease. RELEVANCE AND NOVEL INFORMATION: Rib tumors should be included in a differential diagnosis in cats with extraluminal esophageal stricture. CT should be performed for treatment planning. Surgical treatment was curative in this case.