A 25-year-old woman with a history of systemic lupus erythematosus (SLE) was transferred from an outside hospital with a worsening painful generalized rash and oral ulcerations for the prior 3 weeks due to concern for Stevens-Johnson Syndrome / toxic epidermal necrolysis (TEN). Exam revealed denuded erythematous plaques covering over 80% of the patient’s body surface area and a 4.2 x 2.6 cm ulcerated plaque of the superior hard palate. Histology demonstrated parakeratosis and compact hyperkeratosis overlying an atrophic epidermis with vacuolar interface change, prominent keratinocyte dyskeratosis, and a thickened basement membrane zone (BMZ). The superficial dermis had a mild predominantly lymphocytic perivascular infiltrate and superficial dermal mucin deposition. Direct immunofluorescence was positive for IgG (granular, BMZ), C3 (granular, BMZ), and IgA was negative. Labs were remarkable for positive ANA (1:160), ds-DNA, anti-Smith, anti-RNP, low C3/C4, with negative anti-SSA/SSB. The clinicopathological correlation was most consistent with the diagnosis of TEN-like acute systemic lupus erythematosus (TEN-like ASLE). Our patient improved with treatment for her ASLE. This case highlights a challenging clinicopathologic differential diagnosis.