Spontaneous liver cell adenoma in children.

The clinical and pathologic features observed in five children with spontaneous liver cell adenoma are described. All tumors showed benign biologic behavior. Two patients had untreated tumors that were followed for 5 years and 26 years, respectively, and showed no evidence of malignant transformation; the latter tumor unprecedentedly showed signs of spontaneous regression over time. Unusual physical findings associated with the liver cell adenomas included generalized osteoporosis, urticaria, and koilonychia. Microscopically, the liver cell adenomas were composed of cords, rarely sheets, of neoplastic hepatocytes with negligible pleomorphism and rare to absent mitoses; bile ducts, portal tracts, and central veins were absent. A fibrous capsule was present in all cases. Previously undescribed histologic features of this tumor type included focal extramedullary hematopoiesis and multinucleate giant cell formation in association with tumor necrosis. Benign neoplasms of the type described in this and previous studies probably should be managed conservatively.