A 5-year-old neutered female domestic shorthair cat was referred for acute onset of dyspnoea. Thoracic radiographs performed by the referring veterinarian revealed the presence of pleural effusion. Upon presentation, the cat was dyspnoeic, and cardiopulmonary auscultation revealed muffled heart sounds and bilaterally increased bronchovesicular sounds. Radiographic study of the thorax revealed bilateral pleural effusion and a soft tissue opacity in the dorsocaudal region of the left hemithorax. A whole-body contrast-enhanced CT scan identified a soft tissue mass arising from the left diaphragmatic crus. Transthoracic ultrasound-guided fine-needle aspiration (FNA) of the mass was performed and the result was consistent with a malignant mesenchymal neoplasia, showing giant cells. Cytoreductive surgery was performed and the histopathology diagnosis of undifferentiated pleomorphic sarcoma was made. Adjuvant chemotherapy was then offered. Ten days after surgery pleural effusion recurred. Thoracic echography revealed the presence of a diaphragmatic thickening in the area of surgical resection. FNA of the thickening was consistent with mesenchymal neoplasia. Even when chemotherapy and supportive treatment with pain relief was instituted, the clinical condition of the cat worsened within a few days and it was euthanased 1 month after surgery.

Primary diaphragmatic tumours (PDTs) have been rarely reported in human and in veterinary medicine, where only three cases have been described in the dog. To our knowledge, this is the first report to describe a PDT, specifically an undifferentiated pleomorphic sarcoma, in a cat.

• Anaplastic sarcoma with giant cells
• chemotherapy
• primary diaphragmatic tumour
• surgery
• undifferentiated pleomorphic sarcoma

Primary tumors of the diaphragm are quite rare. About 150 cases have been reported in the literature. Fibrosarcomas are the commonest malignant neoplasms of the diaphragm; however, only a few (less than 20) cases have been reported to date. We present the case of an extremely rare tumor of the diaphragm mimicking a liver mass. The patient, a young 28-year-old woman, presented with an 8-month-history of mildly progressive upper abdominal pain and early fullness after meals. Computed tomography scan of the abdomen revealed a mass located in the region of the left lobe of the liver with non visualized left lobe and partial vascular supply of the mass from the left hepatic artery. The tumor was also seen to draw its vascularity from bilateral internal mammary arteries. Surgical excision and hepatectomy was planned, keeping in mind the diagnosis of an atypical left hepatic mass. Laparotomy revealed a left diaphragmatic tumor growing caudally into the upper abdomen, compressing and splaying the liver along the left medial surface where the tumor was virtually adherent to it. Successful excision of the mass and subsequent histopathological and immunochemistry examination of the specimen revealed low grade fibromyxoid sarcoma of the diaphragm. This case highlights the unusual presentation of a diaphragmatic mesenchymal tumor and how it can be mistaken as an atypical liver mass. It also emphasizes the tumoral vascular supply as an indicator of its organ of origin.

• Diaphragmatic tumor
• Low grade
• Fibromyxoid sarcoma
• Liver mass
• Atypical liver mass
• Computed tomography

• Child
• Child, Preschool
• Diagnosis, Differential
• Diagnostic Imaging
• Humans
• Infant
• Infant, Newborn
• Thoracic Diseases/diagnosis
• Thorax/abnormalities

• Diagnosis, Differential
• Diaphragm/pathology
• Diaphragm/surgery
• Female
• Humans
• Lipoma/diagnosis
• Lipoma/pathology
• Lipoma/surgery
• Middle Aged
• Muscle Neoplasms/diagnosis
• Muscle Neoplasms/pathology
• Muscle Neoplasms/surgery
• Suture Techniques
• Thoracic Surgery, Video-Assisted
• Tomography, X-Ray Computed

• Aged
• Diaphragm
• Humans
• Lipoma/diagnosis
• Lipoma/surgery
• Male
• Thoracic Neoplasms/diagnosis
• Thoracic Neoplasms/surgery