Primary diaphragmatic undifferentiated pleomorphic sarcoma in a cat

Abstract

Case summary 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. Relevance and novel information 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.

Undifferentiated pleomorphic sarcoma (atypical fibroxanthoma‐subtype) in a 4‐year‐old Rothschild's giraffe (Giraffa camelopardalis rothschildi)

“…UPSs have been reported in other species, including humans, dogs, cats, cattle, horses, koi carp and California sea lions 7–12 . UPSs are one of the most commonly reported soft tissue sarcomas in human patients between 50 and 70‐years old.…”

“…Immunopositivity for vimentin may be the only immunohistochemistry (IHC) marker that substantiates mesenchymal origin in these neoplasms 7 ; however, smooth muscle actin (SMA), which is used for identifying smooth muscle tumours, is frequently expressed in UPS, and so positivity does not exclude UPS as a diagnosis in such cases. 10 Other current terms for UPS include giant cell tumour of soft parts, extraskeletal giant cell tumour or anaplastic sarcoma with giant cells; but in all cases, such tumours are generally locally invasive with variable metastatic potential, which reflects the variable origins of these neoplasms. 5 UPSs have been reported in other species, including humans, dogs, cats, cattle, horses, koi carp and California sea lions.…”

“…5 UPSs have been reported in other species, including humans, dogs, cats, cattle, horses, koi carp and California sea lions. [7][8][9][10][11][12] UPSs are one of the most commonly reported soft tissue sarcomas in human patients between 50 and 70years old. The main treatment modality in human medicine is aggressive surgical resection, with local recurrence evident in 13%-42% of patients and metastases in approximately one of three cases.…”

“…UPS in its current usage is the most agreed histopathological term for an anaplastic sarcoma with giant cells, which does not exhibit immunopositivity for specific neoplastic cell lineages, such as CD18 for histiocytic origin, desmin for generic muscle and myofibroblastic neoplasms, or glial fibrillary acidic protein (GFAP) for neurogenic origin, for example, peripheral nerve sheath tumours. Immunopositivity for vimentin may be the only immunohistochemistry (IHC) marker that substantiates mesenchymal origin in these neoplasms 7 ; however, smooth muscle actin (SMA), which is used for identifying smooth muscle tumours, is frequently expressed in UPS, and so positivity does not exclude UPS as a diagnosis in such cases 10 . Other current terms for UPS include giant cell tumour of soft parts, extraskeletal giant cell tumour or anaplastic sarcoma with giant cells; but in all cases, such tumours are generally locally invasive with variable metastatic potential, which reflects the variable origins of these neoplasms 5…”