Rare cutaneous tuberculosis in Sub-Saharan Africa developed on discoid lupus erythematous lesion

Lupus vulgaris is a common presentation of cutaneous tuberculosis (TB), but its ulcerative or vegetating form also called vorax is rare.We report a case of lupus vulgaris in its vorax form, which occurred in a patient with discoid lupus erythematous. A 42-year-old patient monitored for chronic lupus erythematosus consulted again for a facial tumor and fever. Physical examination revealed painful ulcerative and crusted lesions on an old discoid lupus lesion and covered the entire upper lip. Similar lesions were noted on cheeks. Moreover, there were cervical lymphadenopathy, a bilateral pulmonary condensation syndrome, and dysphonia. Cutaneous histopathology had revealed a tuberculoid granuloma without caseating, and nucleic acid amplification tests (GeneXpert®) performed on sputum were positive. Thus, the diagnosis of multifocal TB with skin involvement of vorax type was confirmed. The outcome was favorable following TB treatment. Our observation is distinctive as it is a granulomatosis and ulcerative form of lupus vulgaris, which occurred on a discoid lupus erythematous lesion. This is a rare form of lupus vulgaris. This scarcity can be explained by diagnostic difficulties as there are numerous differential diagnoses and histopathology is not often helpful.