Gastric leiomyoblastoma (epithelioid leiomyoma) occurring in a child: a case report.

Leiomyoblastomas are rare smooth muscle tumors occurring most commonly in the gastrointestinal tract of adults. We report the unusual occurrence of a gastric leiomyoblastoma in a child who presented with refractory iron deficiency anemia. The tumor had a superficial erosion which was apparently the source of intermittent hemorrhage resulting in anemia. Epithelioid cells, spindled cells, and cells arranged in a perithelial pattern were seen by microscopy, characteristic of a leiomyoblastoma. Immunohistochemical staining demonstrated muscle actin, vimentin, desmin, and alpha-1-antichymotrypsin, and electron microscopy showed focal densities alternating with thin filaments. All of these features help to differentiate the tumor from an inflammatory pseudotumor. Leiomyoblastomas are associated with paragangliomas and pulmonary chondromas in children, but these were not present in this child. The prognosis of leiomyoblastomas may be related to tumor size, mitotic rate, and cellular characteristics.