Leiomyosarcomas of the liver are extraordinarily rare tumors. Scott H. Saul states in his chapter on masses of the liver (Diagnostic Surgical Pathology, Edited by Stephen S. Sternberg, Raven Press), that only fourteen cases have been reported in the literature up until 1983, and perhaps a handful have been reported since. Other diagnostic considerations are addressed by the immunoperoxidase panel employed. That the immunoperoxidase staining is negative for the S100 protein argues against this being a malignant neural sheath tumor. The negativity of the cytokeratin staining argues against this being a sarcomatoid or spindle-cell carcinoma. Other factors arguing against a spindle cell carcinoma include the positivity of mesenchymal markers (actin and desmin), and the lack of a background of cirrhosis which is often seen in association with hepatocellular carcinoma. We are unable to account for the vimentin stain being negative (or at best weakly positive) in this case, since one would expect vimentin expressivity in this tumor. While some may suggest the possibility of an epithelioid hemangioendothelioma be considered, the size of the tumor, its overwhelming monomorphic, or rather monophasic nature, the lack of desmoplasia, and the absence of cytoplasmic vacuoles rules this entity out. If this had been an epithelioid hemangioendothelioma, the cytoplasmic vacuoles would have stained positively for Factor VIII antigen, and Weibel-Palade bodies would have been seen on electron microscopy.