Primary Biphasic Hepatic Sarcoma in DICER1 Syndrome

Hidradenocarcinoma of the Chest With Axillary Lymph Node Metastasis: Report of 2 Cases and Systematic Literature Review of a Breast Cancer Mimicker

ABSTRACT

Hidradenocarcinoma (HAC) is a rare malignant neoplasm originating from eccrine sweat glands, often presenting diagnostic challenges because of its resemblance to other malignancies, particularly breast cancer when occurring in the chest region. This report describes 2 cases of HAC with axillary lymph node metastasis, both initially misinterpreted clinically. The first case involved a 63-year-old woman with a sternal mass, near the right breast, initially suspected to be a sebaceous cyst. Histologic examination revealed a solid-cystic epithelial tumor with features suggestive of HAC, confirmed by immunohistochemical analysis. The second case concerned an 81-year-old woman with a subcutaneous growth in the sternal area, also diagnosed as HAC after histopathologic and immunohistochemical assessment. Both cases demonstrated strong estrogen receptor positivity, leading to the recommendation of hormonal therapy. A systematic review of the literature identified 21 similar cases of HAC in the chest wall, highlighting the diagnostic complexities and the potential for these tumors to mimic breast carcinoma. This review underscores the need for careful histologic and immunohistochemical evaluation to differentiate HAC from other malignancies, particularly in the breast region. Given the rare and the potential aggressive nature of HAC, early and accurate diagnosis is crucial for guiding appropriate therapeutic strategies and improving patient outcomes.

Liver-specific DICER1 syndrome model mice develop cystic liver tumors with defective primary cilia

DICER1 syndrome is a tumor predisposition syndrome caused by familial genetic mutations in DICER1. Pathogenic variants of DICER1 have been discovered in many rare cancers, including cystic liver tumors. However, the molecular mechanisms underlying liver lesions induced by these variants remain unclear. In the present study, we sought to gain a better understanding of the pathogenesis of these variants by generating a mouse model of liver-specific DICER1 syndrome. The mouse model developed bile duct hyperplasia with fibrosis, similar to congenital hepatic fibrosis, as well as cystic liver tumors resembling those in Caroli's syndrome, intrahepatic cholangiocarcinoma, and hepatocellular carcinoma. Interestingly, the mouse model of DICER1 syndrome showed abnormal formation of primary cilia in the bile duct epithelium, which is a known cause of bile duct hyperplasia and cyst formation. These results indicated that DICER1 mutations contribute to cystic liver tumors by inducing defective primary cilia. The mouse model generated in this study will be useful for elucidating the potential mechanisms of tumorigenesis induced by DICER1 variants and for obtaining a comprehensive understanding of DICER1 syndrome. © 2024 The Pathological Society of Great Britain and Ireland.

DICER1 Syndrome: A Multicenter Surgical Experience and Systematic Review

DICER1 syndrome is a rare genetic disorder that predisposes patients to the development of malignant and non-malignant diseases. Presently, DICER1 syndrome diagnosis still occurs late, usually following surgical operations, affecting patients' outcomes, especially for further neoplasms, which are entailed in this syndrome. For this reason, herein we present a multicenter report of DICER1 syndrome, with the prospective aim of enhancing post-surgical surveillance. A cohort of seven patients was collected among the surgical registries of Pediatric Surgery at the University of Pisa with the General and Oncologic Surgery of Federico II, University of Naples, and the Pediatric Surgery, Regina Margherita Hospital, University of Turin. In each case, the following data were analyzed: sex, age at diagnosis, age at first surgery, clinical features, familial, genetic investigations, and follow-up. A comprehensive literature review of DICER1 cases, including case reports and multicenter studies published from 1996 to June 2022, was performed. Eventually, the retrieved data from the literature were compared with the data emerging from our cohort of patients.

DICER1-associated sarcoma of the aortic arch - a case report and literature review

Primary sarcoma of the aorta is extremely rare. We herein report a case of DICER1-associated sarcoma originating from the aortic arch. A 45-year-old male was admitted to the hospital with a cold left hand and weakened radial artery pulse in the left side. Computed tomography of the chest showed multiple penetrating ulcers with tumor-like ectasia at the aortic arch, diagnosed as a pseudoaneurysm. Histopathological analysis of the mass revealed a biphasic neoplasm composed of epithelial and mesenchymal components and a transition zone between the epithelial and mesenchymal cells, which supports the diagnosis of a biphasic sarcoma rather than carcinosarcoma. The differentiated cells of soft tissue showed strong and diffuse positivity for TLE-1, Bcl-2, and CD99; the nested epithelial cells were focally positive for CK-pan, but negative for EMA, membranous localization of β-catenin. This case showed a unique pattern of SS18-break-apart probe, with loss of the green signal (approximately 33%) by fluorescence in situ hybridization (FISH). Fusion gene profiling using whole transcriptome RNA sequencing (RNA-seq) indicated that this case was negative for common fusion genes including SS18. Next-generation sequencing (NGS) revealed somatic mutations in DICER1 . Taken together, this case was diagnosed as a DICER-associated biphasic sarcoma of the aortic arch. The patient died four months after aorta replacement therapy without radiotherapy and chemotherapy.

DICER1-associated hepatic cystic neoplasm with pleuropulmonary blastoma-like features: a novel clinicopathologic diagnosis

This report documents a unique multicystic neoplasm of the liver in an 8-month-old boy with a heterozygous germline pathogenic DICER1 variant. This neoplasm, initially considered most likely a mesenchymal hamartoma based on imaging, demonstrated the characteristic histologic pattern of embryonal rhabdomyosarcoma residing in the subepithelial or cambium layer-like zone of the epithelial-lined cysts. Thus, although the differential diagnosis includes mesenchymal hamartoma, a young child with a multicystic mass lesion in the liver, lung, or kidney should both raise the possibility of a germline pathogenic DICER1 variant and also not be mistaken for one of the other hepatic neoplasms of childhood.

DICER1-associated malignancies mimicking germ cell neoplasms: Report of two cases and review of the literature

DICER1 syndrome is characterized by a unique combination of features and a growing list of associated rare tumors. Traditionally, gonadal or extra-gonadal teratomas have not been considered part of this spectrum, with only rare DICER1-related teratoid neoplasms recently reported. Besides, their methylation profiles remain elusive. We report two DICER1-associated malignancies involving the lumbar spine of a 22-year-old man (case 1) and the pelvic cavity of a 14-year-old girl (case 2). Both tumors exhibited teratoma-like features with a high-grade malignant somatic component, including rhabdomyosarcomatous elements for case 1 and a malignant neuroectodermal neoplasm with features of an embryonal tumor with multilayered rosettes (ETMR) for case 2. Both tumors showed strong SALL4 expression and H3K27me3 loss by immunohistochemistry. Next-generation sequencing studies confirmed biallelic DICER1 mutations with additional pathogenic missense mutations in KRAS (case 1) and CTNNB1 (case 2). The methylation profile of case 1 clustered with DICER1-associated sarcomas, whereas case 2 classified as an ETMR (albeit low raw and calibrated score). In conclusion, we report two DICER1-related malignancies with teratoma-like features, further expanding their morphologic spectrum and highlighting the multipotentiality of their presumed cell of origin. Notably, we describe the first ETMR identified outside the CNS with a documented DICER1 biallelic inactivation. Our findings also highlight the potential role of other molecular alterations such as KRAS and CTNNB1 mutations in defining the phenotype of embryonal and primitive DICER1-associated neoplasms, a notion that deserves further studies.