Kervarrec Thibault, Pissaloux Daniel, Paindavoine Sandrine, Tirode Franck, Osio Amélie, Mourah Samia, Jouenne Fanélie, Sohier Pierre, Calonje Eduardo, Pekar Agnes, Luna Evelyn Vanesa Erazo, Goto Keisuke, Delalande Flore, Frouin Eric, Macagno Nicolas, Drouot Françoise, Faisan Monique, Cribier Bernard, Battistella Maxime, de la Fouchardière Arnaud
Department of Pathology, Centre Hospitalier Universitaire de Tours, Université de Tours, Tours, France.
"Biologie des infections à polyomavirus" Team, UMR INRA ISP 1282, Université de Tours, Tours, France.
Histopathology. 2023 Aug;83(2):310-319. doi: 10.1111/his.14940. Epub 2023 May 18.
Poroma is a benign adnexal neoplasm with differentiation towards the upper portion of the sweat gland apparatus. In 2019, Sekine et al. demonstrated recurrent YAP1::MAML2 and YAP1::NUTM1 fusion in poroma and porocarcinoma. Follicular, sebaceous and/or apocrine differentiation has been reported in rare cases of poroma and whether these tumours constitute a variant of poroma or represent a distinctive tumour is a matter to debate. Herein we describe the clinical, immunophenotypic, and molecular features of 13 cases of poroma with folliculo-sebaceous differentiation.
Most of the tumours were located on the head and neck region (n = 7), and on the thigh (n = 3). All presented were adults with a slight male predilection. The median tumour size was 10 mm (range: 4-25). Microscopically, lesions displayed features of poroma with nodules of monotonous basophilic cells associated with a second population of larger eosinophilic cells. In all cases, ducts and scattered sebocytes were identified. Infundibular cysts were present in 10 cases. In two cases high mitotic activity was noted, and in three cases cytologic atypia and areas of necrosis were identified. Whole transcriptome RNA sequencing demonstrated in-frame fusion transcripts involving RNF13::PAK2 (n = 4), EPHB3::PAK2 (n = 2), DLG1::PAK2 (n = 2), LRIG1::PAK2 (n = 1), ATP1B3::PAK2 (n = 1), TM9SF4::PAK2 (n = 1), and CTNNA1::PAK2 (n = 1). Moreover, fluorescence in situ hybridisation (FISH) analysis revealed PAK2 rearrangement in an additional case. No YAP1::MAML2 or YAP1::NUTM1 fusion was detected.
Recurrent fusions involving the PAK2 gene in all analysed poroma with folliculo-sebaceous differentiation in this study confirms that this neoplasm represents a separate tumour entity distinct from YAP1::MAML2 or YAP1::NUTM1 rearranged poromas.
汗孔瘤是一种向汗腺装置上部分化的良性附属器肿瘤。2019年，关根等人证实在汗孔瘤和汗孔癌中存在复发性YAP1::MAML2和YAP1::NUTM1融合。在罕见的汗孔瘤病例中曾有毛囊、皮脂腺和/或顶泌汗腺分化的报道，而这些肿瘤是构成汗孔瘤的一种变体还是代表一种独特的肿瘤尚存在争议。在此，我们描述了13例具有毛囊皮脂腺分化的汗孔瘤的临床、免疫表型和分子特征。
大多数肿瘤位于头颈部（n = 7）和大腿（n = 3）。所有患者均为成年人，男性略多。肿瘤中位大小为10毫米（范围：4 - 25毫米）。显微镜下，病变呈现汗孔瘤特征，有单调嗜碱性细胞结节，伴有另一群较大的嗜酸性细胞。所有病例均发现导管和散在的皮脂腺细胞。10例存在漏斗状囊肿。2例有高有丝分裂活性，3例有细胞学异型性和坏死区域。全转录组RNA测序显示框内融合转录本涉及RNF13::PAK2（n = 4）、EPHB3::PAK2（n = 2）、DLG1::PAK2（n = 2）、LRIG1::PAK2（n = 1）、ATP1B3::PAK2（n = 1）、TM9SF4::PAK2（n = 1）和CTNNA1::PAK2（n = 1）。此外，荧光原位杂交（FISH）分析在另一例中发现PAK2重排。未检测到YAP1::MAML2或YAP1::NUTM1融合。
本研究中所有分析的具有毛囊皮脂腺分化的汗孔瘤中均存在涉及PAK2基因的复发性融合，这证实该肿瘤代表一种与YAP1::MAML2或YAP1::NUTM1重排的汗孔瘤不同的独立肿瘤实体。
