Objective: Our aims were to define the sonographic features of abdominal and pelvic lymphangioleiomyomas in lymphangioleiomyomatosis (LAM) and to evaluate the utility of sonography in visualizing diurnal change in the size of the masses.
Materials and methods: Forty-four patients with LAM and abdominal and pelvic lymphangioleiomyomas found on screening CT underwent sonography. Twenty-two patients had two studies on the same day, one in the morning and the other late in the afternoon.
Results: Forty-nine masses were scanned in the 44 patients. The anatomic distribution of the masses was the following: retroperitoneal (29/44 patients, 66%), pelvic (10/44, 23%), and both retroperitoneal and pelvic (5/44, 11%). Of the 49 masses, 12 (24%) were cystic, 16 (33%) were solid, and 21 (43%) were complex. Twenty-two patients underwent sonography in the morning and afternoon. The masses increased in size between the two studies in all 21 patients in whom the masses were visualized in both studies. In three of 21 patients, the echotexture of the masses changed between the morning and afternoon studies: In two the echotexture changed from solid to complex, and in the other, it changed from hyperechoic to isoechoic relative to the liver.
Conclusion: The sonographic characteristics of lymphangioleiomyomas are similar to some neoplasms such as lymphoma and ovarian cancer (a similarity that sometimes prompts biopsy). After a mass is shown in a patient with LAM, repeat sonography in the morning and afternoon is useful to depict diurnal variation in size and echotexture and to confirm the diagnosis of lymphangioleiomyoma and avoid biopsy.