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Fibrous tumors
Published in Eckart Haneke, Histopathology of the NailOnychopathology, 2017
Originally described as juvenile aponeurotic fibroma (calcifying fibroma) in young children and adolescents with a predilection to the palms and soles,93 this lesion has now also been reported in adults and in nonacral sites.94 It usually presents as a slow-growing, painless, poorly circumscribed, firm mass. There is no preceding trauma.95 The subungual location has not been described, but several cases were localized in the distal phalanx, one even with bone invasion96 and some influence on the nail shape.97
Lipofibromatosis: Central Nervous System Involvement by a Benign Neoplasm
Published in Fetal and Pediatric Pathology, 2023
Alejandra Rebolledo, Laura J. Guerra, Ander EO. Dubón, Mauricio Brindis
Magnetic resonance is the preferred radiological study for the differential diagnosis [24]. The neoplasm is composed predominately of fat with internal (fibrous) septations, and is identified by a variable intensity signal in T1, high intensity signal in T2, with loss of signal with fat suppression and enhancement after contrast administration [7]. Our patient represented a challenge in clinical diagnosis, due to an initial tomography report that was inconsistent with the clinical presentation. Magnetic resonance suggested an infiltrative process that ruled out juvenile fibroma (some central areas of high intensity signal in T2), nuchal type fibroma (tumor mainly constituted by collagen tissue) and calcifying aponeurotic fibroma, but couldn’t exclude fibrous hamartoma of infancy and lipoblastomatosis [7,25].
Lipofibromatosis
Published in Fetal and Pediatric Pathology, 2019
The pathogenesis of lipofibromatosis has largely remained enigmatic. No recurrent genetic aberration had been detected. Recently, Ibraheemi and colleagues identified 8 different genetic fusions in 11 out of 20 cases of lipofibromatosis using FISH, RNA sequencing, and RT-PCR techniques. FN1-EGF fusion, which has been described as the specific genetic aberration in calcifying aponeurotic fibroma, was the only recurrent fusion seen in four cases in this series. Based on this finding and the presence of calcifications in two out of three recurrent cases, the authors suggested that some cases of lipofibromatosis might represent an early phase of calcifying aponeurotic fibroma. The fusions detected involved either ligands (EGF, HBEGF, TGFA) to the epidermal growth factor receptor (EGFR) itself, or other receptor tyrosine kinases (ROS1, RET, PDGFRB). These are all known to activate the PI3K-AKT-mTOR pathway. Thus, deregulation of the PI3K-AKT-mTOR pathway has been suggested as a potential pathogenetic mechanism in the development of lipofibromatosis [4]. The other genetic associations suggested by single case reports are a three-way translocation t(4;9;6)(q21;q22;q24) [8] and occurrence of lower limb lipofibromatosis in a patient with multiple congenital anomalies, i.e., syndactyly, bilateral complete cleft lip and palate, trigonocephaly and atrial septal defect [9].