Nodular Fasciitis With Malignant Morphology and a COL6A2-USP6 Fusion: A Case Report (of a 10-Year-old Boy)

Nodular fasciitis is usually a benign lesion genetically characterized by ubiquitin-specific protease 6 (USP6) rearrangements. We present a case of a 10-year-old boy with a 1.5-week history of a painless mass on the right chest wall, which was excised. A histomorphologically malignant tumor with pronounced pleomorphism, atypical mitotic figures, and a myoid immunophenotype was observed. The methylation profile was consistent with nodular fasciitis and fluorescence in situ hybridization confirmed USP6 rearrangement. Using Archer Fusion Plex (Sarcoma Panel) and RNA sequencing, a collagen, type VI, alpha 2 (COL6A2)-USP6 gene fusion was subsequently identified. Furthermore, DNA clustering analysis also showed a match with nodular fasciitis. During the follow-up of 22 months, no recurrence or metastasis occurred. In conclusion, we describe a clinically benign, histomorphologically malignant mesenchymal neoplasm with a myoid immunophenotype, and a genetic and epigenetic profile consistent with nodular fasciitis. In such cases, molecular analysis is a useful adjunct to avoid unnecessary overtreatment

Prognostic Factors in Epithelioid Hemangioendothelioma: Analysis of a Nationwide Molecularly/Immunohistochemically Confirmed Cohort of 57 Cases

Epithelioid hemangioendothelioma (EHE) is an extremely rare vascular sarcoma with variable aggressive clinical behavior. In this retrospective study, we aimed to investigate prognostic factors based on clinicopathologic findings in a molecularly/immunohistochemically confirmed nationwide multicenter cohort of 57 EHE cases. Patients had unifocal disease (n = 29), multifocal disease (n = 5), lymph node metastasis (n = 8) and/or distant metastasis (n = 15) at the time of diagnosis. The overall survival rate was 71.4% at 1 year and 50.7% at 5 years. Survival did not correlate with sex, age or histopathological parameters. No survival differences were observed between multifocal and metastatic disease, suggesting that multifocality represents early metastases and treatment options are limited in comparison to unifocal disease. In unifocal tumors, survival could be predicted using the risk stratification model of Shibayama et al., dividing the cases into low- (n = 4), intermediate- (n = 15) and high- (n = 3) risk groups. No clinical or histopathological parameters were associated with progressive unifocal disease course. Lymph node metastases at the time of diagnosis occurred in 14.0% of the cases and were mainly associated with tumor localization in the head and neck area, proposing lymph node dissection. In conclusion, our results demonstrate the aggressive behavior of EHE, emphasize the prognostic value of a previously described risk stratification model and may provide new insights regarding tumor focality, therapeutic strategies and prognosis

Calcifying fibrous tumor and inflammatory myofibroblastic tumor are epigenetically related : A comparative genome-wide methylation study

Based on histological findings, calcifying fibrous tumor (CFT) may be a late (burned out) stage of inflammatory myofibroblastic tumor (IMT). This concept, however, has not been proven by molecular means. Five CFTs were analyzed for IMT-related rearrangements in ALK, ROS1 and RET using fluorescence in situ hybridization (FISH). Additionally, genome-wide methylation patterns were investigated and compared with IMT (n = 7), leiomyoma (n = 7), angioleiomyoma (n = 9), myopericytoma (n = 7) and reactive soft tissue lesions (n = 10) using unsupervised hierarchical cluster analysis and t distributed stochastic neighbor embedding. CFT patients, 4 females and 1 male, had a median age of 20 years ranging from 7 to 43 years. Two patients were younger than 18 years old. The tumors originated in the abdomen (n = 4) and axilla (n = 1). Histologically, all lesions were (multi) nodular and hypocellular consisting of bland looking (myo)fibroblasts embedded in a collagenous matrix with calcifications. FISH analysis brought up negative results for ALK, RET and ROS1 rearrangements. However, genome-wide methylation analysis revealed overlapping methylation patterns of CFT and IMT forming a distinct homogeneous methylation cluster with exception of one case clustering with myopericytoma/angioleiomyoma. In conclusion, DNA methylation profiling supports the concept that CFT and IMT represent both ends of a spectrum of one entity with CFT being the burn out stage of IMT