“Necrobiosis lipoidica diabeticorum is seen in 0.3% of patients with diabetes mellitus or impaired glucose tolerance. The lesions may precede the diagnosis of diabetes mellitus by several years. The sharply demarcated reddish-brown plaque with central yellow deposits in the pretibial area is characteristic and a biopsy is not always necessary. Topical corticosteroids are sometimes helpful. Early lesions of necrobiosis lipoidica diabeticorum can be confused with granuloma annulare or sarcoidosis, however, and a biopsy may be helpful. While xanthomas can be flat plaques up to several centimeters in size, they usually occur on flexor surfaces of the limbs along with the trunk and face.” ABFM
