Primary histiocytic sarcoma of central nervous system: a clinicopathological study of three cases / 中华病理学杂志

ABSTRACT

Objective@#To study the clinicopathological features, differential diagnosis and prognosis of primary histiocytic sarcoma of central nervous system(CNS).@*Methods@#Three cases of CNS histiocytic sarcoma were collected at Chinese People′s Liberation Army General Hospital from 2005 to 2018. Their clinicopathological characteristics were analyzed, and the related literature reviewed.@*Results@#The three patients included two females and one male, aged 36, 44, 58 years (median 44 years). MRI showed heterogeneously enhancing lesions which were considered meningioma, high-grade glioma or metastatic carcinoma. Histopathologically there were moderately pleomorphic, mitotically active tumor cells with a loose arrangement, effacing the normal brain tissue. These cells possess abundant eosinophilic cytoplasm, highly atypical nuclei, predominant nucleoli, and hemophagocytosis; multinucleated or spindled forms were also seen, as was background reactive inflammation. The tumor cells were typically positive for CD68, CD163, vimentin and lysozyme, S-100 protein, two of three cases were positive for BRAF V600E,one of three cases was partly positive for CD45, CD45RO, CD4, CD34, and negative for GFAP, Olig-2, CK, EMA, SSTR2, CD99, CD117, MPO, CD1a, Langerin, CD21, CD23, CD35, CD15, CD30, CD38, and CD138. The index of Ki-67 was 30%-75%. Rich reticular fiber network was seen in all cases; BRAF V600E mutation was present in two cases.@*Conclusions@#CNS histiocytic sarcoma is a rare malignant tumor; histopathologic and immunohistochemical examination are necessary for the diagnosis and to exclude other primary CNS and hematolymphopoietic tumors. Primary CNS histiocytic sarcoma is treated by surgery, chemotherapy and radiation therapy, but the prognosis is poor. Complete resection combined with high dose focused radiotherapy can improve the prognosis.