Imaging findings of adiposis dolorosa vs. massive localized lymphedema.

Purpose: Adiposis dolorosa (Dercum's disease) is a condition of benign, painful subcutaneous lipomatous lesions associated with weakness, endocrine and lipid abnormalities, and mental disturbances. There is little information documenting the cross-sectional imaging findings that differentiate it from lipomatous and neoplastic soft tissue masses, or massive localized lymphedema. The purpose of this study was to provide a radiological case series of adiposis dolorosa.

Methods: A 10-year retrospective review of the picture archiving and communications system was performed. Two musculoskeletal radiologists reviewed images to confirm and document imaging features, location, size, and patient demographics. Medical records were reviewed to characterize patients into three groups: one group met at least three of the four criteria of Dercum's syndrome, the second group met less than three criteria, and the third group had clinical diagnosis of cellulitis of the lower extremity.

Results: Seventeen cases (25 masses) of adiposis dolorosa were found, nine cases of which met at least three criteria of Dercum's syndrome. All cases in the first two groups demonstrated skin thickening and lymphedema of subcutaneous fat, which was fluid attenuation on CT and low or intermediate T1-weighted and high STIR/T2-weighted MR signal. Two cases with pathology showed mild fatty infiltration with fibrous septa, and the third case showed massive localized lymphedema. The third group of ten cellulitis patients demonstrated non-mass-like subcutaneous edema with similar CT attenuation and MR signal characteristics to the first two groups, but differed by the presence of post-contrast enhancement and non-mass-like appearance in 90%.

Conclusion: Imaging findings of adiposis dolorosa and massive localized lymphedema overlap, as do the symptoms and pathological features. Due to the mass-like engorgement of the soft tissues and pain, patients will often undergo imaging to exclude neoplasm or infection. Knowledge of these conditions and the characteristic imaging findings is important to prevent unnecessary biopsy and misdiagnosis.