Zelger B, Weinlich G, Steiner H, Zelger B G, Egarter-Vigl E
Department of Dermatology, University of Innsbruck, Austria.
Am J Surg Pathol. 1997 Feb;21(2):235-41. doi: 10.1097/00000478-199702000-00015.
We report five cases of plexiform fibrohistiocytic tumors, three classic subcutaneous lesions and two dermal ones. Both variants had similar profiles and were clinically indistinguishable. The lesions affected the trunk more than the upper extremities and were found in children and young adults (18.4 +/- 12.8 years). They showed a marked female predominance (4:1, including both dermal variants). Clinically, they were skin-colored, hard nodules of 1-2-cm diameter that resulted in such differential diagnoses as fibroma, histiocytoma, pilomatricoma, or cyst. Interestingly, one subcutaneous case with a painful "worms in the sack" presentation was thought to represent a plexiform neurofibroma. Histology revealed well-circumscribed dermal or subcutaneous plexiform lesions with a characteristic biphasic appearance. Most of the tumor bulk consisted of spindle-shaped to stellate myofibroblasts with a variable admixture of collagen or loosening of stroma. In the center of the plexiform strands and nodules, a few osteoclast-like giant cells as well as epithelioid mononuclear cells (< 10%) were found. Myofibroblasts were positive with HHF35 and for smooth muscle actin in three of five cases. Osteoclast-like giant cells were positive with KP1 in all five cases. Both types of cells stained with the macrophage marker Ki-M1p. A broad panel of other markers was negative. This series expands the spectrum of plexiform fibrohistiocytic tumor, but it also broadens the differential diagnosis of (dermal) plexiform lesions, which at present includes spindle cell nevi, schwannomas, neurofibromas, granular cell tumors, nerve sheath myxomas (neurothekeomas), spindle cell lipomas, and tufted angiomas.
我们报告了5例丛状纤维组织细胞瘤，其中3例为典型的皮下病变，2例为真皮病变。两种变体具有相似的特征，临床上难以区分。病变累及躯干多于上肢，见于儿童和青年（18.4±12.8岁）。女性明显居多（4:1，包括两种真皮变体）。临床上，它们为肤色、直径1 - 2厘米的硬结节，可导致纤维瘤、组织细胞瘤、毛母质瘤或囊肿等鉴别诊断。有趣的是，1例皮下病例表现为疼痛的“袋中蠕虫”样，曾被认为是丛状神经纤维瘤。组织学显示真皮或皮下界限清楚的丛状病变，具有特征性的双相外观。肿瘤大部分由梭形至星状的肌成纤维细胞组成，伴有不同程度的胶原混合或间质疏松。在丛状条索和结节的中心，发现了一些破骨细胞样巨细胞以及上皮样单核细胞（<10%）。5例中有3例肌成纤维细胞HHF35和平滑肌肌动蛋白呈阳性。5例中破骨细胞样巨细胞KP1均呈阳性。两种细胞均被巨噬细胞标志物Ki - M1p染色。其他一系列标志物均为阴性。本系列扩大了丛状纤维组织细胞瘤的范围，但也拓宽了（真皮）丛状病变的鉴别诊断，目前包括梭形细胞痣、神经鞘瘤、神经纤维瘤、颗粒细胞瘤、神经鞘黏液瘤（神经鞘瘤）、梭形细胞脂肪瘤和簇状血管瘤。
