Background: Rhinosporidiosis is a disease affecting primarily the mucosa of nose, conjunctiva and urethra. It is endemic in some Asiatic regions, affecting people of any age and sex. Its manifestation is a polypoid mass growing inside the affected cavity and the only treatment is surgical excision. Rhinosporidium seeberi is the aetiological agent. Many discussions arouse regarding the taxonomic classification of the microorganism, recent studies established it is an aquatic protistan parasite. The lesion may recur and sometimes cause osteolytic bone lesions. In endemic areas it is not easy to establish if recurrent lesions are due to relapse or reinfection.

Granulomatous inflammation with multinucleated giant cells is observed in various infectious and noninfectious diseases. It has been found in association with malignant tumors and designated sarcoid-like reaction. The distinction between a tumor-related granulomatous reaction and a true sarcoidosis can be a problematic issue. A case of renal cell carcinoma with sarcomatoid features (Fuhrman nuclear grade IV) with an extensive peritumoral sarcoid-like reaction and a critical review of the few cases of this association described in the literature have been reported, and the problematic clinical and pathological assessments of such lesions are discussed.

Background: Gastrointestinal stromal tumors (GISTs) represent the majority of primary nonepithelial neoplasms of the digestive tract, most frequently expressing the KIT protein detected by the immunohistochemical staining for the CD117 antigen. Extra-gastrointestinal stromal tumors (EGISTs) are neoplasms with overlapping immunohistological features, occurring in the abdomen outside the gastrointestinal tract with no connection to the gastric or intestinal wall.