Fig. 12

49-year-old woman presenting with slowly progressing subcutaneous induration over the right cheek and with extension to the skin over the nose. Clinically, a facial filler injection related complication was suspected as an underlying pathology. On MRI, the infiltrative lesion appeared hypointense on T2 W (arrows in a) and on T1 W images (arrows in b) and showed avid enhancement on post contrast T1 W fat saturated images (arrows in c, d). The lesion involves the superficial and deep layers of the facial fat and the SMAS. Note scattered rounded nonenhancing dark regions (dashed arrows) embedded in the strongly enhancing cutaneous lesion in c) possibly suggesting granulomas. The location of this lesion, as depicted by MRI, is not typical for facial filler injection. Based on MRI features, the presumptive diagnosis of sarcoidosis, dermatomyositis, or cutaneous lymphoma was made and biopsy was recommended. Histopathology revealed sarcoidosis. Subsequent CT of the chest (not shown) showed typical interstitial nodules and mediastinal lymphadenopathy. Retrospective analysis of the head and neck MRI revealed no nodal involvement, in particular no “dark lymph node sign” [84]. Nevertheless, the nonenhancing dark regions in c) corresponded histologically to sarcoid granulomas, the imaging features being strikingly similar to granulomas in nodes with the “dark lymph node sign”