Axial and peripheral arthropathy affects the majority of patients with acromegaly, being a leading cause of morbidity and functional disability. Treatment with octreotide (OCT) improves symptoms and signs of acromegalic arthropathy, but objective detection of structural changes in bone and cartilage has not been reported to date. This open prospective study was designed to evaluate the effect of a long term treatment with OCT on acromegalic arthropathy assessed by ultrasonography examination. Articular cartilage thicknesses of shoulder, wrist, and knee as well as sizes of heel tendons were measured in 30 acromegalic patients (18 with active and 12 with inactive disease) and 18 sex-, age-, and body mass index-matched healthy subjects. The thicknesses of shoulder, wrists and knees articular cartilages and that of heel tendons were significantly increased in patients with active acromegaly compared to those in healthy subjects (P < 0.01). With the exception of shoulder cartilage, significant increases in wrist and knee cartilages (P < 0.01) and right and left heel tendon sizes (P < 0.05) were found in patients with active compared to those with inactive disease. After 6 months of OCT treatment, a significant decrease in shoulder, wrist, and left knee articular cartilage was found (P < 0.001). No significant change was recorded in right knee cartilage or heel tendon size. The decrease in thickness of shoulder and wrist cartilages was more pronounced than that measured at the level of left knee (26.3 +/- 3.3% and 27.2 +/- 4.2% vs. 14.2 +/- 4.2%, respectively; P < 0.05). Ultrasonography is able to reveal articular involvement in acromegalic patients and may be useful to monitor the effect of treatment.