Table 3.

Histopathological features of cutaneous tuberculosis.

Different forms of cutaneous tuberculosis	Histopathological features	Observation of AFB
Well-formed granulomas with absence of caseous necrosis
Lupus vulgaris	epidermis may be atrophic or hypertrophic, featuring acanthosis, papillomatosis and even pseudo-epitheliomatous hyperplasia. Presence of well-formed tuberculous granulomas accompanied more often by Langhans giant cells, or foreign body-like granulomas in the reticular dermis.	infrequent
Lichen scrofulosorum	non-caseating, epithelioid cell granulomas in upper dermis and around dermal appendages	not seen
Intermediate forms: granulomas with caseous necrosis
Tuberculosis verrucosa cutis	marked pseudoepitheliomatous hyperplasia of the epidermis with hyperkeratosis and dense inflammatory cell infiltrate consisting of neutrophils, lymphocytes, and giant cells. The presence of granulomatous infiltrates is a cardinal sign	can be seen
Primary cutaneous tuberculosis	it varies according to the time of inoculation; in recent lesions there is the presence of necrotizing neutrophilic infiltrate with numerous AFB. At a later stage there is organization of granulomas	decreased number
Acute miliary tuberculosis	skin consists of areas of an inflammatory infiltrate composed of lymphocytes, plasma cells, and neutrophils with focal superficial dermal areas of necrosis and abscess formation without true caseating granuloma. The presence of acid-fast bacilli with vascular thrombi is characteristic of these lesions	can be seen
Tuberculosis orificialis	there are tuberculoid granulomas, around a median, central, and superficial ulcer accompanied by caseous necrosis in the deep dermis	not usually found
Papulonecrotic tuberculid	lesions showed psoriasiform epidermal hyperplasia, and epithelioid granulomas with lymphocytes and Langhans giant cells with variable amounts of necrosis seen in the upper and mid dermis with a perifollicular distribution	not usually found
Poorly formed granulomas with intense caseous necrosis
Scrofuloderma	Massive central necrosis with abscess formation and in many cases, suppuration, traces of granulomas can be observed at periphery of the lesions	may be found
Metastatic abscesses and gumma	Central ulceration with abundant caseous necrosis, surrounded by a rim of giant cells and macrophages can be observed	frequently detected