Fig. 4
From: KRAS mutation in secondary malignant histiocytosis arising from low grade follicular lymphoma
Langerhans cell sarcoma. The inguinal lymph node biopsy shows a complete effacement of the lymph node architecture by an abnormal polymorphous infiltrate of histiocytes, small lymphocytes, neutrophils, eosinophils and rare plasma cells, with scattered and focal sheets of atypical large cells with convoluted nuclei (a H&E, 100X, b H&E, 600X). The large cells are CD1a + and S100+ (c CD1a IHC, 600X; d S100 IHC, 600X). The morphology and phenotype is consistent with a diagnosis of Langerhans cell sarcoma. The large cells were CD20-, CD19- (not shown), PAX5- (not shown) and CD10- (e CD20 IHC, 600X; f CD10 IHC, 600X)