Fibrohistiocytic Tumors and Related Neoplasms in Children and Adolescents

Abstract

Fibrohistiocytic tumors (FHTs) in children and adolescents range from the benign fibrous histiocytoma, or dermatofibroma, to a variety of intermediate and malignant neoplasms, such as dermatofibrosarcoma protruberans and high-grade undifferentiated pleomorphic sarcoma (malignant fibrous histiocytoma). Those tumors as a group are comprised of fibroblasts, myofibroblasts, and histiocytes-dendritic cells with a variably prominent inflammatory infiltrate consisting of lymphocytes and eosinophils. Dendritic cells are also a major constituent of another group of neoplasms that include Langerhans cell histiocytosis, follicular and interdigitating cell sarcomas, and juvenile xanthogranuloma. These latter tumors are considered in this discussion for the sake of differential diagnosis and their possible histogenetic relationship to FHTs. Recent studies have suggested that the relationship between the fibroblast and histiocyte in the FHTs may reflect the intrinsic capacity to transdifferentiate from one to the other morphologic and functional state. The so-called “facultative fibroblast,” as a cell with fibroblastic and histiocytic properties, was discussed in the context of the fibrous xanthoma 50 years ago. Possibly the entire histogenetic concept of FHTs should be reconsidered in light of current studies.

Pediatric dermatohistopathology – histopathology of skin diseases in newborns and infants

“…The typical lipidized cytoplasm, which imparts the characteristic yellow hue, and xanthomatous multinucleated giant cells (Touton giant cells) only become visible after a while (Figure 11e, f). Unlike Langerhans cell histiocytosis, juvenile xanthogranuloma is positive for CD163, CD68, CD4, HLA-DR, and factor XI-IIa, but in almost all cases negative for S-100 and CD1a, consistent with dermal dendrocytes or plasmacytoid monocytes as their postulated cell of origin [61,62]. Other non-Langerhans cell histiocytosis, such as benign cephalic histiocytosis (of childhood), differ in terms of their clinical, but not their histological, findings.…”

Pädiatrische Dermatohistopathologie – Histologie von Dermatosen im Neugeborenen‐ und Säuglingsalter

“…Histologisch finden sich dichte, nichtepidermotrope Infiltrate aus primär spindeligen Histiozyten (Abbildung c, d), welche erst nach längerer Bestandsdauer das den gelben Farbton hervorrufende, typische lipidisierte Zytoplasma sowie xanthomatöse mehrkernige Riesenzellen vom Touton‐Typ aufweisen (Abbildung e, f). Im Gegensatz zur Langerhanszell‐Histiozytose ist das juvenile Xanthogranulom positiv für CD163, CD68, CD4, HLA‐DR und Faktor XIIIa, jedoch in nahezu allen Fällen negativ für S‐100 und CD1a, entsprechend dermalen Dendrozyten oder plasmazytoiden Monozyten als postulierte Ursprungszelle . Weitere Non‐Langerhanszell‐Histiozytosen wie die benigne zephale Histiozytose des Kindesalters unterscheiden sich hinsichtlich des klinischen, nicht jedoch des histologischen Bildes.…”

Tumeurs des tissus mous

“…Il peut s'observer à tout âge mais surtout entre 30 et 50 ans [51,442] . L'HCF est constitué d'un tissu fibreux comportant une proportion variable d'éléments histiocytaires ou xanthomateux ainsi que des fibroblastes organisés en faisceaux .…”

“…Elle se traduit par un nodule sous-cutané indolore, centimétrique bien délimité, ou parfois par une localisation plus profonde (muscle, viscère, os) de taille plus importante (3 cm ou beaucoup plus) [51] . Elle survient à tout âge, un peu plus chez l'homme et aux extrémités .…”

“…Elle survient à tout âge, un peu plus chez l'homme et aux extrémités . Les métastases se voient dans moins de 5 % des cas [51,182] . L'aspect est celui d'un nodule bien délimité, possiblement remanié (hémorragie, zones kystiques ou myxoïdes, nécrose) .…”