Toxic epidermal necrolysis syndrome versus mycosis fungoides

We present a case in which our patient was first seen with biopsy and histologically confirmed toxic epidermal necrolysis syndrome (TENS). Subsequent to recovery and discharge from the hospital, the patient reappeared within 2 months of her discharge with a rash over her neck and back, with a central area of superficial breakdown. Biopsy results confirmed this lesion to be mycosis fungoides, not a recurrent case of TENS. Given the time lag between these two clinical courses, it is easy to speculate that this patient only had one disease entity, which we failed to diagnose on initial presentation. Once the skin becomes manifest with mycosis fungoides, the lesions are those typically beginning as an erythrodermic rash, it then progresses to indurated and infiltrated purple plaques. These symptoms may be confused with TENS, particularly in a patient with a preexisting diagnosis of TENS. It is critical that histologic confirmation of the clinical diagnosis be confirmed so that the treatment of the patient can be correctly instituted.