Adenomyoepithelioma Located Over the Tibial Tuberosity
A 41-year-old Russian female visited our clinic with a chief complaint of tenderness over a lump on the right tibial tuberosity. It had been present for 20 years without pain or changes in size and level of tenderness. In physical examination, an approximately 2×2 cm soft, round-shaped mobile mass was detected. Severe tenderness was noted, but neither abnormal sensation nor decreased mobility was evident. Plain radiography revealed increased soft tissue density immediately below the right tibial tuberosity (). Ultrasonography showed a hypoechoic multinodular lesion in the subcutaneous fat layer ().\nUnder local anesthesia, a 4-cm longitudinal incision was made below the tibial tuberosity, through which a salmon-colored mass measuring 2×2×1 cm was noted in the subcutaneous fat layer () without adhesion to the adjacent tissue or bursitis. The mass was excised, taking care to minimize adjacent soft tissue damage. Histologic examination revealed the mass was composed of glandular structures lined by epithelial cells and surrounded by multiple layers of myoepithelial cells (). On immunohistochemical analysis, the inner epithelial cells was strongly positive for cytokeratin 7 (CK7) and the myoepithelial cells positively reacted to p63.\nPostoperatively, neurological symptoms were not observed. The patient was satisfied with disappearance of tenderness after the excision of the tumor. At six months after surgery, there were no signs of complications and recurrence.