Carcinoma de células escamosas pulmonar com metástase para o intestino delgado em um gato / Squamous cell carcinoma of the lung with small intestine metastasis in a cat

ABSTRACT

Background: Primary lung tumors in cats are mainly classified into adenocarcinoma arising from peripheral pulmonaryepithelium and, in a smaller number of cases, into adenosquamous or squamous carcinoma, bronchioloalveolar carcinoma,and carcinoid tumor. There are few reports in the international literature describing lung cancer metastasis to visceral organs in cats, especially with regard to squamous tumors. This report describes the clinical pathological, histological, andimmunohistochemical findings of lung squamous cell carcinoma with metastasis to small intestine in a cat.Case A female, Siamese, unneutered, adult cat presented with an unhealed ulcerative crusted lesion on the left ear, previously diagnosed as squamous cell carcinoma (SCC). Six months later, the cat returned presenting with increased volumein the left pelvic limb and claudication due to severe osteolysis in metatarsal and tarsal bones, as shown in radiographicexaminations. The limb was amputated forty day later, but it did not undergo histological examination. The cat died fourteendays after amputation and underwent necropsy. Macroscopically, significant changes were observed in the small intestine,including serous segmental necrotizing and hemorrhagic lesion with luminal stenosis and corrugation of mucous surface,which was covered with a fibrinopurulent pseudomembrane. Palpation of lung parenchyma showed small firm nodules.There was an ulcerative crusted lesion on the left ear. Histopatological examination revealed infiltration of pleomorphicneoplastic epithelial cells disrupting the architecture of small intestine and lung, with pronounced anisocyitosis and anisokaryosis. The neoplastic cells had indistinct borders; their cytoplasm was eosinophilic and pleomorphic and varied frommoderate to abundant in amount; and their nuclei...