Diagnosis: Lupus vulgaris
Description: Lupus vulgaris is the commonest form of cutaneous tuberculosis with a myriad of clinical presentations. It occurs in patients previously sensitized to Mycobacterium tuberculosis with a moderate to high degree of immunity. Classically, it starts as a soft brownish red papule or nodule that gradually expands by involution in one area with expansion in another, gradually progressing over a period of many years to form a well-defined skin coloured to erythematous plaque with an “apple jelly nodule” appearance on diascopy. Other variants may include keratotic, hypertrophic, nodular, and psoriasiform.
Morphology: Plaque
Site: Buttocks
Sex: M
Age: 55
Type: Clinical
Submitted By: Shahbaz Janjua
Differential DiagnosisHistory:
This 55 year old man presented with several year history of an extremely slowly progressing, mildly pruritic large plaque on the left buttock. On examination, a large well defined erythematous plaque covered with adherent psoriasiform scale was present on the left gluteal region. Areas of atrophic scarring were noted interspersed with areas of activity.