Jacobson-Dunlop Erick, White Clifton R, Mansoor Atiya
Department of Pathology, Oregon Health and Science University, Portland, 97239, USA.
Am J Dermatopathol. 2011 Aug;33(6):551-6. doi: 10.1097/DAD.0b013e318206a648.
Plexiform fibrohistiocytic tumor (PFHT) is a mesenchymal neoplasm of intermediate malignant potential, which typically presents as a dermal or subcutaneous nodule, and is therefore often sampled by skin punch biopsy where diagnostic features may be subtle or absent. We retrospectively analyzed a series of 6 cases of PFHT to highlight for dermatopathologists the features of PFHTs useful to distinguish it from the other entities in the differential diagnosis. On the basis of the proportion of spindled fibroblastic cells to histiocytoid nodules in the biopsy specimen, we divided PFHT into 3 histologic variants: cellular, fibrous, and mixed. The biopsies also were compared with the final resection specimens, in an attempt to determine which histologic features in the original biopsies were most helpful in establishing a diagnosis. Clinical follow-up and immunohistochemistry were performed on all cases. The cellular and mixed variants were a lesser diagnostic challenge inasmuch as the distinctive features were more easily identifiable in small punch biopsy specimens. The fibrous variant proved more difficult to diagnose. Features most helpful in the diagnosis of PFHT were biphasic appearance with small, cellular, histiocytoid aggregates and accompanying plump spindled cells in the deep dermis and subcutis. Negative staining for CD34, NK1/C3, factor XIIIa, and beta-catenin by immunohistochemistry proved useful in excluding some of its mimics.
丛状纤维组织细胞瘤（PFHT）是一种具有中等恶性潜能的间叶性肿瘤，通常表现为真皮或皮下结节，因此常通过皮肤穿刺活检取材，而其诊断特征可能不明显或缺失。我们回顾性分析了6例PFHT病例，旨在向皮肤病理学家强调PFHT在鉴别诊断中有助于与其他实体相区分的特征。根据活检标本中梭形纤维母细胞与组织细胞样结节的比例，我们将PFHT分为3种组织学变型：细胞型、纤维型和混合型。还将活检标本与最终切除标本进行比较，以确定原始活检中的哪些组织学特征对确诊最有帮助。对所有病例均进行了临床随访和免疫组化检查。细胞型和混合型在诊断上的挑战较小，因为其独特特征在小的穿刺活检标本中更容易识别。纤维型则较难诊断。对PFHT诊断最有帮助的特征是在真皮深层和皮下组织呈现双相外观，伴有小的、细胞性的、组织细胞样聚集物以及相伴的丰满梭形细胞。免疫组化显示CD34、NK1/C3、因子ⅩⅢa和β-连环蛋白呈阴性染色，有助于排除一些与之相似的病变。
