Duodenal leiomyosarcoma in a cat: Cytologic, pathologic, and immunohistochemical findings

Abstract

A 7‐year‐old mixed‐breed neutered male cat was presented with a history of chronic vomiting with increased frequency in the last month, progressing to depression and profuse projectile vomiting. Abdominal ultrasonography revealed an area of marked segmental duodenal thickening associated with a nodule, and euthanasia was performed due to a poor prognosis. Grossly, at the postmortem examination, the wall of a duodenal segment was severely expanded by a nodule measuring 5.0 cm in diameter, resulting in marked luminal narrowing and obstruction. Smears were made by scraping the cut surface of the tumor during the postmortem examination. The smears were highly cellular and contained mesenchymal cells arranged individually or in large non‐cohesive aggregates. Cells varied in morphology from spindle to round to stellate‐shaped with marked anisocytosis and anisokaryosis. Numerous bi‐ and multinucleated neoplastic cells were observed. Histologic examination revealed a densely cellular neoplastic proliferation of mesenchymal cells that effaced the duodenal submucosa, muscularis externa, and serosa layers. Most cells were spindle‐shaped; however, some tumor areas had numerous round cells and bi‐ and multinucleated neoplastic cells. Spindle cells showed variable cytoplasmic immunoreactivity for vimentin, smooth muscle actin, and desmin. Round, bi‐, and multinucleated giant cells only had marked multifocal cytoplasmic immunoreactivity for vimentin. Neoplastic cells did not have immunoreactivity for cytokeratin, GFAP, S100, and CD117. A final diagnosis of duodenal leiomyosarcoma was made. This article reports the pathologic, cytologic, and immunohistochemical findings of this case and discusses the main differential diagnoses in cases of intestinal sarcomas in domestic animals.

Pathological Findings in Gastrointestinal Neoplasms and Polyps in 860 Cats and a Pilot Study on miRNA Analyses

“…Morphological and molecular genetic findings in feline intestinal carcinomas have been described in detail by Groll and colleagues [29]. Furthermore, mast cell tumours [30][31][32][33] and sarcomas [34][35][36][37][38] have been reported in the feline gastrointestinal tract.…”

Primary retropharyngeal leiomyosarcoma in a young cat

“…1 Surgery is the recommended treatment of choice and the prognosis depends on the anatomical location of the tumour and the presence of metastasis. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] To the authors' knowledge, this report describes a novel diagnosis of retropharyngeal leiomyosarcoma in a young cat with a good outcome following marginal surgical excision. This tumour should be considered as a differential diagnosis for a retropharyngeal mass in the cat.…”

“…Chromatin was finely stippled to coarsely clumped with 1–3 small nucleoli per cell. Neoplastic cells exhibited moderate to marked anisocytosis and anisokaryosis with a mitotic count of 1 per 10 high-power fields at × 200 magnification and an area of 2.37 mm 2 ( Figure 4 ). Immunohistochemistry revealed diffuse strong staining of the neoplastic cells with antivimentin (1:500 dilution [Monoclonal Mouse Anti-Human Vimentin Clone; Dako]), antidesmin (1:100 dilution [Monoclonal Mouse Anti-Human Desmin Clone; Dako]) and anti-alpha smooth muscle actin (1:100 dilution [Monoclonal Mouse Anti-Human Smooth Muscle Actin Clone; Dako]) antibodies at × 200 magnification ( Figures 5 and 6 ), consistent with a leiomyosarcoma.…”

“…Leiomyosarcomas are uncommon, malignant tumours arising from smooth muscle cells 1 and have been reported in the duodenum, 2 iliocaecocolon, 3 large intestine, 1 urinary bladder, 4 stomach, 5 oesophagus, 6 spleen, 1 uterus, 7 pancreas, 8 liver, 9 kidney, 10 vulva, 11 eye, 12 cutaneous smooth muscle, 13 , 14 and dermal interphalangeal region 15 and heart. 16 They are frequently non-encapsulated and invasive tumours.…”

“…Surgery is the recommended treatment of choice and the prognosis depends on the anatomical location of the tumour and the presence of metastasis. 2 – 16 …”