Pleuropulmonary blastoma (PPB) and other DICER1-associated high-grade malignancies are morphologically, genetically and epigenetically related – A comparative study of 4 PPBs and 6 sarcomas

Thyroblastoma: A DICER1‐associated embryonal neoplasm and fine needle aspiration diagnostic criteria

“…30 Other DICER1-related malignancies can also have some histologic features that are similar to thyroblastoma, despite arising in a different anatomical site. [33][34][35][36] DICER1-mutated neoplasms frequently include (1) cellular mesenchymal proliferations with variable rhabdomyoblastic differentiation, (2) primitive neuroepithelial blastema, (3) islands of immature cartilage or bone, and (4) epithelium with differentiation towards the organ of origin. 37 The distinction between tumors in this group is usually based on the location of the tumor, the differentiation of the epithelial components, and clinical history.…”

Genomic characterization of DICER1-associated neoplasms uncovers molecular classes

“…Eligible participants signed an informed consent form. Clinical data, histological features and/or sequencing results of 403/534 tumors have previously been reported elsewhere in part 14 – 16 , 21 , 24 , 27 , 35 – 64 . Wherever available, H&E-stained formalin-fixed paraffin-embedded (FFPE) sections from tumors samples were reviewed by pathologists involved in the study (FKFK, UF, MG, BAC, BCG, CSBC, FK, US, CK, WGM, AvD).…”

“…These features comprise a subepithelial layer of malignant mesenchymal cells (cambium layer), areas of rhabdomyoblastic differentiation with positive staining for myogenin and myoD1, cellular/immature and occasionally malignant cartilage, foci of bone/osteoid and areas of anaplasia 10 – 13 . Furthermore, we have recently shown that both ERMS with DICER1 PVs and a tumor entity termed “primary intracranial sarcoma, DICER1 -mutant” (PIS DICER1) are associated with DNA methylation signatures that are distinct from their morphological counterparts that are not DICER1-associated 14 – 16 . This finding, together with our recent speculations regarding the histomorphological similarities between DICER1-associated sarcomas 11 – 13 arising at different sites led us to question whether in general, DICER1-associated tumors share common features such that they represent a distinct tumor entity, arising at various anatomical locations.…”

Type II pleuropulmonary blastoma mistaken for rhabdomyosarcoma: A case report

“…Histologically, PPB is characterized by a mixture of blastemal islands with high mitotic activity and areas of undifferentiated loose mesenchymal spindle cells. Initially, due to the presence of rhabdomyoblastic features, particularly in PPB type III, PPB was thought to represent a RMS of the lung [9] , [10] .…”

“…PPB remains the most well-known DICER1-related malignant tumor, up to 80 % of patients with PBP carrying a DICER1 mutation [11] . DICER1 mutations have been associated with an increased risk of several other types of tumors, including genitourinary embryonal RMS, Wilms tumor, anaplastic sarcoma of the kidney, Sertoli-Leydig cell tumors of the ovary, and others [10] . The wide spectrum of associated tumors underscores the importance of recognizing DICER1 syndrome in pediatric patients with unusual or multiple tumor types.…”