AbstractWe report a case of testicular hamartomas in association with Cowden disease. Clinical examination of the patient, a 39‐year‐old man, revealed a palpable mass in the right side of the scrotum. Sonographic examination showed that the mass was either a spermatocele or an epididymal cyst and that multiple hyperechoic lesions were present in both testes. On subsequent MRI, the appearance of these lesions was consistent with that of fat‐containing hamartomas. Testicular biopsy was not performed, but follow‐up serial sonographic examination was recommended. To our knowledge, this report is the first to describe testicular hamartomas as a probable manifestation of Cowden disease. © 2003 Wiley Periodicals, Inc. J Clin Ultrasound 31:481–483, 2003