Calcifying Nested Stromal-Epithelial Tumor of the Liver: An Update and Literature Review.

Calcifying nested stromal-epithelial tumor is a rare entity that has gone by a variety of names in the literature: ossifying malignant mixed epithelial and stromal tumor, ossifying stromal-epithelial tumor, and desmoplastic nested spindle cell tumor of the liver. To our knowledge, approximately 38 cases have been reported in the literature. The histogenesis is still largely unknown but histopathologically is characterized by nests of spindle and epithelioid cells in an organoid arrangement surrounded by a prominent dense myofibroblastic stroma with occasional psammomatous calcification and focal heterotopic ossification. Vascular invasion is rare and tumoral recurrence is uncommon with only a single reported case of metastasis leading to death. Treatment is mainly by surgical intervention with the role of chemotherapy seeming limited, but lack of data hinders a true recommendation. It is important to rule out other processes such as hepatoblastoma, calcified hemangioma, synovial sarcoma, metastatic gastrointestinal stromal tumor, desmoplastic small round cell tumor, among others, which appear similar radiographically and histopathologically.