De novo histoid leprosy in a Colombian patient with multiple skin nodules on the ears and extremities

Abstract

Histoid leprosy is an uncommon form of lepromatous leprosy with distinct clinical, histopathological, immunological, and bacteriological features. This variant usually occurs in multibacillary patients who have irregular or inadequate treatment. Herein, we report a case of de novo histoid leprosy diagnosed in a patient from Cali, Colombia. In endemic areas, histoid leprosy should be in the differential diagnosis of any patient presenting with skin nodules. Early diagnosis and appropriate treatment are recommended for mitigating the impact of histoid leprosy cases, which are important reservoirs of Mycobacterium leprae.

Histoid leprosy in a young man

“…Unusual clinical manifestations of HL may mimic various dermatological entities, e.g. molluscum contagiosum, sarcoidosis, lobomycosis, leishmaniasis, keloid, reticulohistiocytosis, neurofibromatosis, tumor-like masses, figuratelike lesions and xanthomas [4,5]. The clinical features and distribution of cutaneous lesions in our patient closely resembled those of sarcoidosis.…”

Authors’ response to “De novo histoid leprosy-further points to be discussed”

“…Histoid leprosy can occur as a relapsing or recurrent disease on lepromatous leprosy and other forms of multibacillary leprosy, even when there is no history of inadequate or irregular therapy 3,4 . Although irregular treatment and inadequate dapsone monotherapy are arguably the most common scenarios, cases of histoid leprosy have also been reported in patients treated with adequate doses of multibacillary-multidrug therapy (dapsone, clofazimine, rifampin) 5 as well as in de novo (untreated) patients 1,3,6 , as reported in our article. Patients with lepromatous leprosy who have received adequate treatment may develop leprosy as early as within 5 years following the cure, but also up to 20 years later 7 , prompting strict monitoring and epidemiological surveillance.…”

“…Histoid leprosy may even go unnoticed by experts, thereby requiring a high clinical suspicion, especially in patients without apparent health concerns. A complete physical examination for epistaxis, skin nodules and thickening of nerves; histopathological examination of skin biopsy specimens from papules, nodules, plaques or tumorlike lesions; and skin smear examination (bacilloscopy) of the earlobes, nose, and elbows are all critical for early and accurate diagnosis of histoid leprosy 1,2 .…”

Histoide Lepra bei einem jungen Mann

“…Ungewöhnliche klinische Manifestationen von HL können verschiedene dermatologische Entitäten imitieren. Dazu gehören Molluscum contagiosum, Sarkoidose, Lobomykose, Leishmaniose, Keloid, Retikulohistiozytose, Neurofibromatose, tumorähnliche Veränderungen, figurierte Läsionen und Xanthome [4,5]. Die klinischen Merkmale und die Verteilung der kutanen Läsionen bei unserem Patienten ähnelten einer Sarkoidose.…”

“…Es wird spekuliert, dass die zellvermittelte und humorale Immunantwort auf M. leprae bei HL-Patienten stärker ist als bei Patienten mit lepromatöser Lepra. Dies zeigt sich in einer erhöhten CD36-Expression durch Keratinozyten sowie einer erhöhten Anzahl von CD4-T-Lymphozyten und B-Lymphozyten [4]. Die Unfähigkeit der Makrophagen, M.-leprae-Bakterien aufzunehmen und ein fokaler Immundefekt kann zu einer hohen Zahl von AFB in HL-Läsionen führen [2,3].…”