A 3-year-old, female spayed, Pug-cross dog presented with a 2-year history of nasal congestion and focal facial deformity. Complete surgical excision was elected following nasopharyngoscopy, endoscopic biopsy and subsequent computed tomography (CT) scan. Nasopharyngoscopy revealed a friable, polypoid mass of the right nasal conchae occluding the right nasal passage. Biopsies of the mass showed expansion of the submucosa by dense bundles of well-differentiated smooth muscle cells that were strongly immunoreactive for ⍺-smooth muscle actin and desmin. Post-procedure CT revealed a large space-occupying mass in the nasal cavity with minimal lysis of the adjacent calvarium. Histology following complete excision confirmed the results obtained on the initial endoscopic biopsy. The final diagnosis was smooth muscle hamartoma.

一只 3 岁、已绝育的雌性哈巴狗有 2 年的鼻塞和局部面部畸形病史。在鼻咽镜检查、内窥镜活检和随后的计算机断层扫描 (CT) 扫描后选择完全手术切除。鼻咽镜检查显示右侧鼻甲有一个易碎的息肉状肿块，阻塞了右侧鼻道。肿块的活检显示黏膜下层被分化良好的平滑肌细胞的密集束扩张，这些细胞对 ⍺-平滑肌肌动蛋白和结蛋白具有强烈的免疫反应性。术后 CT 显示鼻​​腔中有一个大的占位性肿块，相邻颅骨的溶解很小。完全切除后的组织学证实了最初的内窥镜活检结果。最终诊断为平滑肌错构瘤。