Fibrolipomatous hamartoma: 35-year-old female with congenital macrodactyly of the left hand and history of benign tumor masses requiring multiple surgical excisions. The patient presented with progressive enlargement of the index and ring finger PIP joints with chronic numbness of radial and dorsal left hand and dorsum of index and ring fingers. Coronal (a) and axial (b) T1W non-fat-suppressed images demonstrate fatty proliferation of the median nerve. Postoperative changes from prior middle finger resection are seen on the coronal image. Sagittal T2W fat-saturated (c) image demonstrates diffuse enlargement of the median nerve with bands of low signal intensity, compatible with fatty infiltration of the median nerve. Axial T1W (d) image of the contralateral hand shows lipomatous overgrowth of the middle and ring fingers, in keeping with macrodystrophia lipomatosa. Coronal T1W (e) imaging of this same patient at the age of seven demonstrated marked soft tissue hypertrophy and enlargement of the right upper extremity, consistent with known macrodystrophia lipomatosa.