Indeterminate cell tumor of the spleen.

Indeterminate cell tumor is an extremely rare neoplasm that mainly occurs in the skin. We report a case of indeterminate cell tumor arising from the spleen, a previously unreported site for indeterminate cell tumor. Histologically, the tumor showed nests, nodules, and sheets of large polygonal cells with mostly oval nuclei; open chromatin; variable nucleoli; and abundant, eosinophilic cytoplasm.