Martinez Anthony P, Zou Youran, Billings Steven D, Folpe Andrew L
Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota.
Department of Pathology, Cleveland Clinic Foundation, Cleveland, Ohio.
J Cutan Pathol. 2018 Feb;45(2):99-103. doi: 10.1111/cup.13068. Epub 2017 Dec 10.
Epithelioid benign fibrous histiocytoma has been considered a variant of fibrous histiocytoma, but is now considered a distinct entity, typically showing ALK expression. Most show typical morphological features, including an epidermal collarette and large, bland, epithelioid cells. We have recently encountered 2 examples showing an unusual pattern of pericellular calcification, a previously unreported finding.
Available slides were reviewed and clinical follow-up was obtained.
These lesions occurred on the chins of a 16-year-old and 19-year-old female and showed prominent pericellular calcification in addition to otherwise-typical features of epithelioid fibrous histiocytoma. By immunohistochemistry, both lesions were intensely positive for ALK protein. Clinical follow-up (available for 1 case) showed the patient to be disease-free 5 months after excision.
To the best of our knowledge, epithelioid fibrous histiocytomas showing "chondroblastoma-like" calcification have not been previously reported. The chief significance of this finding seems to be in its potential for confusion with other calcifying tumors of the skin and subcutis. Awareness that epithelioid fibrous histiocytomas may show this unusual morphological finding, careful morphological evaluation and ancillary immunohistochemical studies, including ALK protein, should allow for their confident diagnosis in essentially all instances.
上皮样良性纤维组织细胞瘤曾被认为是纤维组织细胞瘤的一种变体，但现在被视为一种独特的实体，通常表现为ALK表达。大多数表现出典型的形态学特征，包括表皮领圈和大的、温和的上皮样细胞。我们最近遇到了2例显示细胞周围钙化异常模式的病例，这是一个以前未报道过的发现。
回顾可用的切片并获得临床随访结果。
这些病变发生在一名16岁和一名19岁女性的下巴上，除了具有上皮样纤维组织细胞瘤的典型特征外，还显示出明显的细胞周围钙化。免疫组化显示，两个病变的ALK蛋白均呈强阳性。临床随访（1例可用）显示患者切除术后5个月无疾病。
据我们所知，以前尚未报道过显示“成软骨细胞瘤样”钙化的上皮样纤维组织细胞瘤。这一发现的主要意义似乎在于它可能与皮肤和皮下组织的其他钙化性肿瘤相混淆。认识到上皮样纤维组织细胞瘤可能表现出这种不寻常的形态学发现，进行仔细的形态学评估和辅助免疫组化研究，包括ALK蛋白检测，应该能够在几乎所有情况下对其进行准确诊断。
