Fine needle aspiration cytology of the spleen of tumor bearing mice

Fine needle aspiration cytology (FNAC) of the spleen was performed in 10 tumor bearing mice. The vascularized spleens were mobilized and re-located under the skin in order to facilitate fine needle biopsy (FNB). Samples of spleen cells thus obtained were studied and the lymphoid cells characterized and counted according to morphology. Owing to a relative decrease in numbers of lymphocytes during tumor growth a very marked intrasplenic increase in numbers of granulocytes was observed. The splenograms of a mouse rejecting the tumor were different from those of tumor bearing mice. FNAC of the spleen is a reliable method for monitoring immunocompetence in individual tumor bearing animals.