XXXX With Lineage Infidelity/Plasticity: A Diagnostic Challenge and Insight Into the Pathobiology of the Disease.

@entity1 @entity4896 @entity9184 @entity404 @entity39 @entity5 @entity1489 @entity986 @entity27239 @entity3138 @entity876 @entity12910 @entity5823 @entity74 @entity3 @entity1583 @entity2281 @entity320
UNASSIGNED: Langerhans cell sarcoma is a very rare and aggressive @entity5 of Langerhans cell lineage, for which aberrant expression of T-cell-related antigens has not yet been reported in a primary @entity1489 . The authors describe the first known case of a primary @entity27239 with lineage infidelity and use comparative genomic hybridization to investigate the genetic composition of the @entity5 and detect DNA copy number alterations throughout its entire genome. The case involves a 62-year-old @entity1 who presented with an irregular nodule on the forehead surrounded by smaller lesions in its vicinity. The clinical impression was @entity320 with satellitosis. The biopsy specimen showed an epidermotropic @entity5 with moderate-to-marked cellular pleomorphism and significantly increased mitotic rate but no @entity39 . The immunoprofile of the lesion was remarkable, as next to common Langerhans cell markers: @entity9184 , @entity4896 , @entity2281 , and @entity404 ; it also exhibited an aberrant T-cell phenotype with the expression of @entity3138 , CD3, and @entity12910 . In addition, fascin and @entity5823 were also expressed, further exaggerating potential diagnostic pitfalls. Langerhans cell lineage was confirmed by the demonstration of characteristic Birbeck granules on electron microscopy. Whole genome analysis for copy number changes and loss of heterozygosity showed a complex karyotype with variable @entity74 . Significant findings included a homozygous deletion at 9p21 involving the @entity986 and loss of heterozygosity at 17p involving @entity876 gene, coupled with a @entity876 missense mutation. Despite reexcision and multiagent systemic chemotherapy, the @entity1 died of @entity3 2 years after diagnosis. This case is an outstanding example of lineage infidelity in a @entity1583 and the utilization of comparative genomic hybridization in characterizing its @entity74 .
