An abdominal desmoid tumor involving the xyphoid and costal chondrium associated with pregnancy: report of a case.

We report herein the case of a 27-year-old woman found to have an abdominal desmoid tumor involving the xyphoid and costal chondrium associated with pregnancy. The patient was referred to our department on the third day after delivery for investigation of a fist-sized, firm tumor in the infrasternal angle, first noticed during the eighth month of gestation. Computed tomography and magnetic resonance imaging revealed a well-defined mass, 9 x 7.5 cm in size, invading the xyphoid. The tumor could be radically excised with the xyphoid, a lower part of sternum, and the chondrium of the bilateral sixth and seventh ribs, including 1.5 cm of free margin. The resected specimen measured 10 x 11.5 x 11.5 cm and weighed 395 g. Histological examination revealed the lesion to be a desmoid tumor consisting of spindle cells with small, elongated nuclei infiltrating dense collagenous fibers. The patient had an uneventful postoperative course and was discharged on the 11th postoperative day. There has been no evidence of recurrence in the 6 months since her operation. This case is of interest with regard to the possible contribution of sex hormones, especially estrogen, to desmoid tumor development.