Localization

 lymph nodes
 spleen (rare) (#11914634#)
 testis (rare) (#10478677#)

Microscopical synpopsis

 diffuse proliferation of large pleomorphic cells
 erythrophagocytosis

Immunohistochemistry

 S-100+
 fascin+
 vimentin+
 CD68+

 CD45-
 CD20-
 CD3-
 CD1a-
 CD30-
 complement receptors-
 CD34-
 Factor VIII-
 HMB-45-
 lysozyme-

Ultrastructurally

 complex interdigitating cytoplasmic dendritic processes
 Birbeck granules absent

References

 Kawachi K, Nakatani Y, Inayama Y, Kawano N, Toda N, Misugi K. Interdigitating dendritic cell sarcoma of the spleen: report of a case with a review of the literature. Am J Surg Pathol. 2002 Apr;26(4):530-7. Review. PMID: #11914634#

 Gaertner EM, Tsokos M, Derringer GA, Neuhauser TS, Arciero C, Andriko JA. Interdigitating dendritic cell sarcoma. A report of four cases and review of the literature. Am J Clin Pathol. 2001 Apr;115(4):589-97. Review. PMID: #11293908#