ALK-Rearranged Mesenchymal Neoplasm With Hyaline-Vascular Castleman Disease-Like Features: A Case Report.

IF 3.4 4区医学 Q2 PATHOLOGY

Pathology International Pub Date : 2025-09-26 DOI:10.1111/pin.70052

Haruna Yagi, Akira Satou, Yasunori Enomoto, Mayu Fujihiro, Yuichi Yamada, Yukihiro Yokoyama, Satoshi Baba, Toshihide Iwashita, Kennosuke Karube

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Abstract

Recent reports have revealed various morphological features of ALK-rearranged mesenchymal neoplasms but their characteristics remain to be elucidated. Here, we report a case of ALK-rearranged mesenchymal neoplasm with novel morphological features. A 32-year-old man had an intra-abdominal mass measuring 75 mm in diameter. Histologically, the tumor consisted of many lymphoid follicles with wide fibrosis or hyalinization. The follicles were characterized by regressed germinal centers and expanded mantle zones. Hyalinized blood vessels were distributed in the follicular and interfollicular areas. These histological findings resembled those of hyaline-vascular type unicentric Castleman disease (HV-UCD). However, the fibrous areas exhibited histological findings similar to inflammatory myofibroblastic tumor (IMT), which is characterized by the proliferation of spindle or stellate-shaped fibroblastic cells accompanied by lymphoid, eosinophil, and plasma cell infiltration. Immunohistochemically, ALK-positive spindle cells were observed in the follicular, interfollicular, and fibrous areas. Molecular analysis revealed fusion between ATIC (exon 7) and ALK (exon 20). Immunofluorescence staining suggested that ALK-positive tumor cells in follicular areas were derived from CD23-positive follicular dendritic cells, and those in interfollicular areas were derived from α-SMA-positive fibroblastic reticular cells or myofibroblasts. Therefore, we report an extremely rare case of ALK-rearranged mesenchymal neoplasm with features of both HV-UCD and IMT.

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alk重排间充质肿瘤伴透明血管样Castleman病1例

最近的报道揭示了alk重排间充质肿瘤的各种形态学特征，但其特征仍有待阐明。在此，我们报告一例alk重排间充质肿瘤，具有新颖的形态特征。32岁男性，腹部内有直径75毫米的肿块。组织学上，肿瘤由许多淋巴样滤泡组成，伴广泛纤维化或透明化。毛囊的特点是生发中心退化，包皮区扩大。滤泡区和滤泡间区可见透明血管。这些组织学表现与透明血管型单中心Castleman病（HV-UCD）相似。然而，纤维区表现出与炎性肌纤维母细胞瘤（IMT）相似的组织学表现，其特征是纺锤形或星状纤维母细胞增生，并伴有淋巴细胞、嗜酸性粒细胞和浆细胞浸润。免疫组织化学，在滤泡区、滤泡间区和纤维区观察到alk阳性梭形细胞。分子分析显示ATIC（外显子7）和ALK（外显子20）融合。免疫荧光染色提示滤泡区alk阳性肿瘤细胞来源于cd23阳性的滤泡树突状细胞，滤泡间区alk阳性肿瘤细胞来源于α- sma阳性的成纤维网状细胞或肌成纤维细胞。因此，我们报告一例极罕见的alk重排间充质肿瘤，同时具有HV-UCD和IMT的特征。

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来源期刊

Pathology International 医学-病理学

CiteScore

4.50

自引率

4.50%

发文量

102

审稿时长

12 months

期刊介绍： Pathology International is the official English journal of the Japanese Society of Pathology, publishing articles of excellence in human and experimental pathology. The Journal focuses on the morphological study of the disease process and/or mechanisms. For human pathology, morphological investigation receives priority but manuscripts describing the result of any ancillary methods (cellular, chemical, immunological and molecular biological) that complement the morphology are accepted. Manuscript on experimental pathology that approach pathologenesis or mechanisms of disease processes are expected to report on the data obtained from models using cellular, biochemical, molecular biological, animal, immunological or other methods in conjunction with morphology. Manuscripts that report data on laboratory medicine (clinical pathology) without significant morphological contribution are not accepted.