Eosinophilic granuloma of the parietal bone of an adult patient with BRAF mutation

Abstract

The paper describes a case of eosinophilic granuloma of the parietal bone in a 32-year-old man. Histological examination revealed a large number of bean-shaped Langerhans cell histiocytes with lobed nuclei and nuclear grooves. The histiocytes alternated with the foci of obvious eosinophilic infiltration and with eosinophilic microabscesses. There were osteoclast-like multinucleated giant cells, bone resorption, and numerous bone rods covered with osteoblast chains. The histiocytes expressed CD1α, langerin, CD68, S100, and p53 (in 90.0% of the tumor cells). The Ki-67 proliferation index was 18.0%. A molecular genetic study identified BRAFV600E mutation (nucleotide substitution s.1799 T>A (p.V600E) in the heterozygous state). Clinical and morphological data and the results of molecular genetic studies led to the conclusion that there was eosinophilic granuloma of the right parietal bone (the unifocal form of Langerhans cell histiocytosis (LCH), type I, group A1, with the monoossal nature of lesion and with BRAFV600E mutation). In adults, this disease is extremely rare (2-5 cases of LCH per million people, bone loss in the fourth decade of life in 2.5% of the patients).

A rapidly expanding calvarial Langerhans cell histiocytosis with low Ki-67 in an adult: a challenging diagnosis on magnetic resonance imaging

“…5 and Dolzhansky et al. 6 were 20%, 18%, 10%., and 6.2%, respectively. However, the result of the Ki-67 proliferative index in our case is unexpectedly lower than the reported results, with a value of about 5%, but the rapid extension and aggression is more prominent when compared to them.…”

“…Although the Ki-67 proliferative index represents the proliferative rate of tumours and many studies have been performed to correlate this index with tumour progression, there are only a few case reports that showed aggressive calvarial unifocal LCH characterised by high Ki-67 nuclear antigen expression in the current literature. 4–7 The results of nuclear expression of Ki-67 antigen at the labelling index reported by Carangelo et al., 4 Fujimura et al., 7 Bruno et al. 5 and Dolzhansky et al.…”

“…Although the Ki-67 proliferative index represents the proliferative rate of tumours and many studies have been performed to correlate this index with tumour progression, there are only a few case reports that showed aggressive calvarial unifocal LCH characterised by high Ki-67 nuclear antigen expression in the current literature. [4][5][6][7] The results of nuclear expression of Ki-67 antigen at the labelling index reported by Carangelo et al, 4 Fujimura et al, 7 Bruno et al 5 and Dolzhansky et al 6 were 20%, 18%, 10%., and 6.2%, respectively. However, the result of the Ki-67 proliferative index in our case is unexpectedly lower than the reported results, with a value of about 5%, but the rapid extension and aggression is more prominent when compared to them.…”