Giant cell tumor of bone mimicking metastatic renal cell carcinoma: a case report

Tumefactive Fat Necrosis with Multinucleate Giant Cell Reaction Mimicking Recurrent Renal Cell Carcinoma following Percutaneous Renal Cryoablation

Multinucleate Giant Cell (GC) reaction is a biological response that occurs secondary to infection, an implanted foreign body, tissue injury, or inflammation. In rare instances GC reactions have been reported following tissue ablation. Multinucleate GC reactions and tumefactive fat necrosis both have the ability to mimic cancer recurrence or metastasis and can appear as enhancing masses. We discuss a case of a surgically resected retroperitoneal perinephric mass thought to be recurrent renal cell carcinoma (RCC) that was pathologically confirmed as tumefactive fat necrosis with multinucleate GC reaction 2 years following percutaneous cryoablation of a small renal mass.

CD10 and CD138 can be expressed in giant cell tumor of bone: An immunohistochemical study

Giant cell tumor of bone (GCTB) is a primary bone neoplasm which is characterized by the presence of mononuclear cells (MCs) and osteoclast-like multinucleated giant cells (MNGCs). Up to our knowledge, CD10 immunoreactivity in GCTB has not yet been studied, and only one study touched on CD138 immunoreactivity in GCTB. The objective of this study is to investigate the immunoreactivity of CD10 and CD138 in GCTB. We offer a discussion of our findings in the context of the differential diagnosis, particularly in small biopsy material. We retrieved and reviewed 15 well-documented cases of GCTB from January 2008 to December 2014. Well-controlled standard immunohistochemical satins were performed on these cases for CD10 and CD138 and few other selected antibodies. Immunoreactivity for CD10 was membranous and was found in 14 (93%) cases. This immunoreactivity was found only in the MCs, whereas the MNGC were all negative. CD138 showed variable positivity in 11 (73%) while 4 (37%) were completely negative. Similar to CD10, staining for CD138 was only seen in the MC; however, the immunoreactivity was predominantly concentrated in the peri-vascular areas. Most of GCTB cases can show variable immunoreactivity for CD10 and CD138. The aforementioned immune-expression raise the possibility of a role in the pathogenesis of GCTB. Paying attention to this immunoreactivity is recommended when considering the clinical and radiological differential diagnosis, especially in small biopsy specimens.