A 2-day-old female piglet was submitted with multiple congenital, nodular skin masses located on the head, neck, trunk and legs. Histopathological examination revealed the presence of nodular, cutaneous tumours with a biphasic growth pattern and comprising a population of undifferentiated, oval or slightly polygonal, frequently perivascularly located cells and a population of spindle-shaped, fibroblast-like cells arranged in bundles. Multifocally, tumour cells infiltrated subcutaneous adipose and muscular tissue. Immunohistochemically, the undifferentiated tumour cells expressed vimentin and calponin, whereas the spindle-shaped tumour cells were positive for vimentin, α-smooth muscle actin and calponin. Based on these findings, the diagnosis was myofibroblastic tumours closely resembling the multicentric form of human infantile myofibromatosis.

一头 2 日龄雌性仔猪的头部、颈部、躯干和腿部有多处先天性结节性皮肤肿块。组织病理学检查显示存在具有双相生长模式的结节性皮肤肿瘤，包括一群未分化的、椭圆形或略呈多边形的、经常位于血管周围的细胞群和一群成束排列的纺锤形、成纤维细胞样细胞群。多灶性，肿瘤细胞浸润皮下脂肪和肌肉组织。免疫组织化学上，未分化的肿瘤细胞表达波形蛋白和钙调蛋白，而纺锤形肿瘤细胞表达波形蛋白、α-平滑肌肌动蛋白和钙调蛋白阳性。基于这些发现，诊断为肌纤维母细胞肿瘤，与人类婴儿肌纤维瘤病的多中心形式非常相似。