Genes, Chromosomes & Cancer最新文献

COL1A1::PDGFB fusion uterine sarcoma is a rare uterine mesenchymal tumor with some clinicopathological features that overlap with those of soft tissue dermatofibrosarcoma protuberans. However, the varied clinicopathologic and genetic characteristics have not been fully revealed, which may be a potential pitfall for diagnosis. Here, we present a case of COL1A1::PDGFB fusion-positive uterine sarcoma in a 49-years-old female. Histologically, the tumor from the initial marginal excision predominantly exhibited high-grade fibrosarcomatous and myxofibrosarcoma-like appearances, while a low-grade focal area displaying storiform growth was identified in the residual tumor after subsequently extended resection. Immunohistochemically, the high-grade components mainly exhibited focal positivity for CD34 and mutated-type p53 immunoreactivity, whereas the low-grade component showed diffuse positivity for CD34 and wild-type p53 staining. The COL1A1::PDGFB fusion was confirmed by fluorescence in situ hybridization and next-generation sequencing. In addition, the TERT-124 C > T mutation was further identified in this lesion's fibrosarcomatous and classic storiform components. To the best of our knowledge, this is the first described case of COL1A1::PDGFB fusion uterine sarcoma with a TERT promoter mutation, which might be a novel genetic finding associated with tumorigenesis of this rare tumor.

We present two cases of malignant ossifying fibromyxoid tumor (OFMT) which eluded diagnosis due to compelling clinicopathologic mimicry, compounded by similarly elusive underlying molecular drivers. The first is of a clavicle mass in a 69 year-old female, which histologically showed an infiltrative nested and trabeculated proliferation of monomorphic cells giving rise to scattered spicules of immature woven bone. Excepting SATB2 positivity, the lesion showed an inconclusive immunoprofile which along with negative PHF1 FISH led to an initial diagnosis of high-grade osteosarcoma. Next generation sequencing (NGS) revealed a particularly rare CREBBP::BCORL1 fusion. The second illustrates the peculiar presentation of a dural-based mass in a 52 year-old female who presented with neurologic dyscrasias. Sections showed a sheeted monotonous proliferation of ovoid to spindle cells, but in contrast to Case #1, the tumor contained an exuberance of reticular osteoid and woven bone deposition mimicking malignant osteogenic differentiation. NGS showed a novel CREBZF::PHF1 fusion. Both tumors recurred locally less than 1 year post-operatively. As such we reiterate that careful morphologic examination is axiomatic to any diagnosis in our discipline, but this paradigm must shift to recognize that molecular diagnostics can provide closure where traditional tools have notable limitations.

Polyketide synthase (pks) island harboring Escherichia coli are, under the right circumstances, able to produce the genotoxin colibactin. Colibactin is a risk factor for the development of colorectal cancer and associated with mutational signatures SBS88 and ID18. This study explores colibactin-associated mutational signatures in biallelic NTHL1 and MUTYH patients. Targeted Next Generation Sequencing (NGS) was performed on colorectal adenomas and carcinomas of one biallelic NTHL and 12 biallelic MUTYH patients. Additional fecal metagenomics and genome sequencing followed by mutational signature analysis was conducted for the NTHL1 patient. Targeted NGS of the NTHL1 patient showed somatic APC variants fitting SBS88 which was confirmed using WGS. Furthermore, fecal metagenomics revealed pks genes. Also, in 1 out of 11 MUTYH patient a somatic variant was detected fitting SBS88. This report shows that colibactin may influence development of colorectal neoplasms in predisposed patients.

Substantial progress has been made in understanding the molecular pathways associated with vascular tumors over the last two decades. In addition to mutations and copy number aberrations, fusions have emerged as significant contributors to the pathogenesis of a notable subset of vascular tumors. In this report, we present a case of an unusual intradermal vascular tumor with epithelioid cytomorphology. Immunohistochemistry revealed diffuse positivity for CD31, ERG and Factor VIII, supporting its endothelial lineage. RNA sequencing (ArcherFusion Plex) revealed the presence of an in-frame fusion between the genes TPM3 Exon 8 and ALK Exon 20. Immunohistochemistry confirmed ALK expression by the endothelial cells. To our knowledge, this is the first documented case of a vascular tumor harboring an ALK fusion. It may fall within the spectrum of epithelioid hemangiomas; nevertheless, we cannot definitively exclude the possibility of it being a distinct and potentially unique benign entity on its own.

Mesenchymal spindle cell tumors with kinase fusions, often presenting in superficial or deep soft tissue locations, may rarely occur in bone. Herein, we describe the clinicopathologic and molecular data of eight bone tumors characterized by various kinase fusions from our files and incorporate the findings with the previously reported seven cases, mainly as single case reports. In the current series all but one of the patients were young children or teenagers, with an age range from newborn to 59 years (mean 19 years). Most tumors (n = 5) presented in the head and neck area (skull base, mastoid, maxilla, and mandible), and remaining three in the tibia, pelvic bone, and chest wall. The fusions included NTRK1 (n = 3), RET (n = 2), NTRK3 (n = 2), and BRAF (n = 1). In the combined series (n = 15), most tumors (73%) occurred in children and young adults (<30 years) and showed a predilection for jaw and skull bones (40%), followed by long and small tubular bones (33%). The fusions spanned a large spectrum of kinase genes, including in descending order NTRK3 (n = 6), NTRK1 (n = 4), RET (n = 2), BRAF (n = 2), and RAF1 (n = 1). All fusions confirmed by targeted RNA sequencing were in-frame and retained the kinase domain within the fusion oncoprotein. Similar to the soft tissue counterparts, most NTRK3-positive bone tumors in this series showed high-grade morphology (5/6), whereas the majority of NTRK1 tumors were low-grade (3/4). Notably, all four tumors presenting in the elderly were high-grade spindle cell sarcomas, with adult fibrosarcoma (FS)-like, malignant peripheral nerve sheath tumor (MPNST)-like and MPNST phenotypes. Overall, 10 tumors had high-grade morphology, ranging from infantile and adult-types FS, MPNST-like, and MPNST, whereas five showed benign/low-grade histology (MPNST-like and myxoma-like). Immunohistochemically (IHC), S100 and CD34 positivity was noted in 57% and 50%, respectively, while co-expression of S100 and CD34 in 43% of cases. One-third of tumors (4 high grade and the myxoma-like) were negative for both S100 and CD34. IHC for Pan-TRK was positive in all eight NTRK-fusion positive tumors tested and negative in two tumors with other kinase fusions. Clinical follow-up was too limited to allow general conclusions.

Dedifferentiated chondrosarcoma is a subtype of chondrosarcoma with a biphasic histological appearance of a chondrosarcoma component transitioning to a high-grade, noncartilaginous sarcoma. It is particularly difficult to confirm the diagnosis when a sarcoma lacking cartilaginous component occurs at a distant location from the primary lesion. The patient was a 72-year-old woman with multiple lesions in the pelvis, lungs, and liver, 18 months after resection of grade 2 central chondrosarcoma of the sternum. Imaging showed no cartilage component in any location. Although a needle biopsy from the pelvic region confirmed the diagnosis as high-grade sarcoma without a cartilage component, it was difficult to distinguish between a new primary sarcoma and metachronous metastatic lesions from patient's known prior dedifferentiated chondrosarcoma. We therefore performed a comparative molecular analysis by whole-exome sequencing of the biopsy sample and the resected sternal central chondrosarcoma. Both lesions had no IDH1/2 mutations but shared 19 somatic mutations and wide-range chromosomal losses, indicating similar origin. This case illustrates the challenge is coupling a diagnosis of metastatic dedifferentiated chondrosarcoma when no chondroid component is evident. Our study also highlights the benefit of genomic analysis in this differential diagnosis, especially in the context of dedifferentiated chondrosarcoma lacking IDH1/2 mutations.

Glomus tumors are classified as members of the perivascular myoid family of tumors. Nearly half of these show NOTCH-gene fusions and a smaller subset has BRAF V600E mutations. Here, we report a novel ATG7::RAF1 fusion in malignant glomus tumor occurring in a 40-year-old female which has not been reported in the malignant glomus tumor before. A 40-year-old female presented with a persistent lateral heel pain and an increase in the size of a mass along the lateral ankle for nearly 10 years. Resected specimen showed a well circumscribed lesion composed of spindled and epithelioid cells with moderate nuclear atypia and mitotic figures (7/10 high-power fields) including atypical forms without any necrosis, lymphovascular, or perineural invasion. The tumor was positive for smooth muscle actin, smooth muscle myosin heavy chain, H-caldesmon, collagen type IV, and discovered on gastronintestinal stromal tumors-1 but negative for AE1/3, desmin, S-100, CD34, and CD117. RNA sequencing showed presence of ATG7-RAF1 fusion. This fusion has not been reported in the malignant glomus tumor before. Future studies on larger cohorts are needed to ascertain the biological significance of these tumors with novel gene fusions.

Spindle cell mesenchymal neoplasms are a diverse and often challenging diagnostic group. While morphological impression is sufficient for some diagnoses, increasingly immunohistochemical and even molecular data is required to render an accurate diagnosis, which can lead to the characterization of new entities. We describe five cases of novel mesenchymal neoplasms with rearrangements in the NCOA2 and NCOA3 genes partnered with either CTCF or CRTC1. Three tumors occurred in the head and neck (palate, auditory canal), while the other two were in visceral organs (lung, urinary bladder). All cases occurred in adults (range 33–86) with a median age of 42 and fairly even sex distribution = (male-to-female = 3:2). Morphologically, they had similar features consisting of monotonous, bland spindle to ovoid cells with fascicular and reticular arrangements in a myxohyaline to collagenous stroma. However, immunophenotypically they had essentially a null phenotype, with only two tumors staining partially for CD34 and smooth muscle actin. Targeted RNA sequencing detected in-frame CTCF::NCOA2 (one case), CRTC1::NCOA2 (two cases), and CTCF::NCOA3 (two cases) fusions. Treatment was surgical resection in all cases. Local recurrence and/or distant metastases were not observed in any case (median follow-up, 7.5 months; range, 2–19 months). Given their morphologic, immunohistochemical, and molecular similarities, we believe that these cases may represent an emerging family of low-grade NCOA2/3-rearranged fibroblastic spindle cell neoplasms.

DICER1-mutated rhabdomyosarcoma is a rare, emerging entity with a predilection for the gynecologic and genitourinary tracts. We report here a case of DICER1-mutated rhabdomyosarcoma of the ovary in a 14 years old girl which displayed interspersed mature teratoid glands, neuroectodermal rosettes and immature blastematous-like tubes. Morphologically the sarcomatous component predominated, corresponding to a high grade spindle cell rhabdomyosarcoma with botryoid features. Islets of cartilage were present. The sarcomatous proliferation encased the teratoid glands, forming cambium layer-like arrangements. The sarcoma cells were Myogenin and MYOD1 positive, the neuroectodermal rosettes expressed SALL4 along with cytokeratins and EMA and were negative for Inhibin; immature blastematous-like tubes were negative for SALL4 and Inhibin. Whole RNA- and targeted DNA-sequencing revealed two DICER1 mutations in exon 26: c.5113G>A: p.(Glu1705Lys) and exon 12: c.1642C>T: p.(Gln548X). The sarcomatous component harbored a complex genetic profile while the teratoid component was diploid, none of the above displayed abnormality of 12p. DICER1-mutated sarcomas display pathological features similar to embryonal rhabdomyosarcomas, botryoid type. They also display heterogeneous features combining cartilage foci, teratoid mature glands, immature blastematous-like tubes and/or neuroectodermal components. Molecular testing remains necessary to confirm the diagnosis. Further studies need to clarify the nosology of DICER1-mutated sarcomas and devise specific therapeutic strategies.

The classification of many soft tissue tumors remains subjective due their rarity, significant overlap in microscopic features and often a non-specific immunohistochemical (IHC) profile. The application of molecular genetic tools, which leverage the underlying molecular pathogenesis of these neoplasms, have considerably improved the diagnostic abilities of pathologists and refined classification based on objective molecular markers. In this study, we describe the results of an international collaboration conducted over a 3-year period, assessing the added diagnostic value of applying molecular genetics to sarcoma expert pathologic review in a selected series of 84 uncommon, mostly unclassifiable mesenchymal tumors, 74 of which originated in soft tissues and 10 in bone. The case mix (71% historical, 29% contemporary) included mostly unusual and challenging soft tissue tumors, which remained unclassified even with the benefit of expert review and routine ancillary methods, including broad IHC panels and a limited number of commercially available fluorescence in situ hybridization (FISH) probes. All cases were further tested by FISH using a wide range of custom bacterial artificial chromosome probes covering most of known fusions in sarcomas, whereas targeted RNA sequencing was performed in 13 cases negative by FISH, for potential discovery of novel fusion genes. Tumor-defining molecular alterations were found in 48/84 tumors (57%). In 27 (32%) cases the tumor diagnosis was refined or revised by the additional molecular work-up, including five cases (6%), in which the updated diagnosis had clinical implications. Sarcoma classification is rapidly evolving due to an increased molecular characterization of these neoplasms, so unsurprisingly 17% of the tumors in this series harbored abnormalities only very recently described as defining novel molecularly defined soft tissue tumor subsets.