Biphasic malignant tumours of the abdominal cavity.

Carcinosarcomas (CS) are uncommon, highly aggressive, biphasic tumours consisting of both sarcomatous and carcinomatous elements. They appear to originate from a common cell of origin, either via transformation from a single premature precursor or conversion of a mature epithelial cell through an epithelial-mesenchymal transition. CS should be considered a unique cancer subtype with cells typically displaying diffuse mitotic activity and widespread atypical mitoses predisposing to early metastasis and a tendency to local recurrence following resection. This review addresses the pathophysiology of CS and discusses its presentation, natural history and management at a variety of sites within the abdominal cavity and retroperitoneum.

Clinicopathological and Prognostic Features of 67 Cases with Pulmonary Sarcomatoid Carcinoma: An 18-Year Single-Centre Experience.

INTRODUCTION: Pulmonary sarcomatoid carcinoma (PSC) is a very rare subtype of non-small-cell lung cancer (NSCLC). It is frequently diagnosed in the advanced stage and is resistant to conventional chemotherapeutics. Due to the unique nature and rarity, we evaluated the epidemiological, clinicopathological, and survival data of PSC patients treated at our centre. PATIENTS AND METHODS: We retrospectively collected demographic and clinical data of 67 PSC patients from a single tertiary referral hospital, between the 2000 and 2018. Univariate and multivariate analyses were performed to determine the risk factors affecting survival. RESULTS: The median age was 61 years, and the percentage of male was 74.6%. Most of the patients had a smoking history (76.9%). The most common PSC subtype was pleomorphic carcinoma (46.3%). The median overall survival (OS) was 55.4 months, and the 5-year OS rate was 47.5%. Advanced stage, T4 tumour, and positive lymph node involvement were associated with poor OS (p < 0.05). The patients with negative epithelial markers had poorer prognosis (p = 0.027) and had more frequently stage IV disease (p = 0.016). Surgical treatment and stage IV disease were determined to be independent prognostic factors. CONCLUSION: PSC is an extremely rare and aggressive variant of NSCLC. Positive epithelial markers may have favourable prognostic significance in PSC. Resection of the tumour with a negative surgical margin is crucial for better survival. The prognosis of the disease is very poor in the metastatic stage.

Basal Cell Adenoma of the Salivary Gland and Possible Recurrence as Basal Cell Adenocarcinoma in a Black-tailed Prairie Dog (Cynomys ludovicianus).

We describe a black-tailed prairie dog (Cynomys ludovicianus) with a benign biphasic nodular tumour that recurred as a malignant biphasic tumour at the same site 2 years after resection. Both tumours were biphasic with regard to the glandular epithelium and basal cells and contained little of the mucus, cartilage or fibrous tissue that characterize pleomorphic adenoma and carcinoma ex-pleomorphic adenoma. Both the first and second tumours exhibited histopathological features similar to those exhibited by human basal cell adenoma and adenocarcinoma, respectively. Both were resected and the animal was alive with no recurrence or metastasis at the time of writing, 9 months after the second surgery.

Spindle Cell Carcinoma of the Mandibular Gingiva - A Case Report.

Spindle cell carcinoma is a malignancy of epithelial origin often mimicking its mesenchymal counterpart thus posing a diagnostic challenge. It is a rare biphasic malignant tumour mostly encountered in the upper aerodigestive tract. The chief differential diagnoses of spindle cell carcinoma are true superficial sarcomas and they especially need to be differentiated from fibrosarcoma. This presentation reports a spindle cell carcinoma of the gingiva and highlights the difficulties encountered in the diagnosis. It also emphasizes the importance of accurate and thorough diagnosis of malignant spindle cell lesions to determine the appropriate therapeutic modality.

A non-joint tissue biphasic synovial sarcoma in a dog.

A subcutaneous tumour was identified in the malar region of a 14-year-old neutered female mixed breed dog. The dog was humanely destroyed and necropsy examination was performed. The tumour did not invade neighbouring tissues and no metastasis was found. Microscopically, the tumour showed a range of features including the presence of multinucleated giant cells, chondrocyte differentiation and cystic or slit-like structures. All of these features are consistent with previously reported descriptions of synovial sarcomas in dogs. Mesenchymal cells accounted for the majority of the tumour, but cytokeratin-positive epithelioid components were also confirmed by immunohistochemistry. The tumour was diagnosed as a biphasic type of synovial sarcoma. Synovial sarcoma in man may develop in tissues unrelated to joints and this is the first report of a non-joint synovial sarcoma in a dog.