| Abstract|| |
Histoid leprosy is a rare form of multibacillary leprosy with distinct clinical and histopathological features. It is a variant of lepromatous leprosy with a very high bacterial index. It appears in patients as a relapse after dapsone monotherapy, in the presence of dapsone resistance or rarely 'de-novo'. It is a matter of concern as we found three cases of de-novo Histoid that too in 3 months from February 2013 to April 2013; in post-global leprosy elimination era. We report three cases presenting with 'de-novo' Histoid Hansen's disease, with no history of leprosy or exposure to dapsone/multi-drug therapy, with heavy bacillary index. The above cases proved to be an eye opener to us in more than one senses. We are reporting these cases just to create awareness and avoid misdiagnosis which will help in prompt treatment and avoid its spread as well as avoid complications and deformities associated with it.
Keywords: Dapsone resistance, De novo, Histoid hansen
|How to cite this article:|
Vora RV, Pilani AP, Mehta MJ, Chaudhari A, Patel N. De-novo Histoid Hansen cases. J Global Infect Dis 2014;6:19-22
| Introduction|| |
Histoid leprosy is an uncommon variant of lepromatous leprosy, characterized by cutaneous/subcutaneous nodules and plaques present over apparently normal skin, with unique histopathological findings, characteristic bacterial morphology and very high bacillary index. The term Histoid leprosy was coined by Wade as a histological concept of bacillary-rich leproma composed of spindle-shaped cells, along with the absence of globus formation (so conspicuous in ordinary leproma). It exhibits a fibromatoid tendency in the chronic form.  It occurs in lepromatous patients who relapse after the dapsone monotherapy in presence of dapsone resistance or even de novo and occasionally seen in unstable borderline and intermediate type of leprosy too. Responsible factors may include: Resistance to dapsone, irregular, and inadequate therapies or mutant organism - Histoid bacillus.
It is a matter of concern as we found three cases of de novo Histoid over a period of 3 months from non-endemic area of Gujarat, India. A fresh focus on de novo histoid leprosy is the primary objective of this article, especially in the context in post-global leprosy elimination era.
| Case Reports|| |
A 29-year-old female presented with multiple grouped papular lesions over lower part of face and abdomen with few hypopigmented patches over buttocks since 2 months.
There was no history of fever, epistaxis or loss of chappals. No complaint of any ulcer or deformity of hands and feet.
There was no h/o contact with leprosy patients. No h/o any drug intake for leprosy.
On examination there were multiple shiny papulo-nodular lesions over lower part of face ([Figure 1]; Case 1) with few hypopigmented scaly lesions over buttocks. Bilateral ulnar nerves were thickened. Crude touch and fine touch were normal. Hot and cold sensations were altered below knees in both legs. Corneal and conjunctival sensations were normal. Motor examination was normal. All routine investigations were normal.
|Figure 1: Clinical pictures of all three cases showing multiple shiny papulo-nodular lesions over face|
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On histopathological examination: The microphotograph shows thinned out epidermis with chronic inflammatory infiltrate which shows storifirm pattern consisting of lymphocytes, histiocytes, and foamy macrophages. Heavy bacillary load was seen on Fite Faraco stain [Figure 2]. Split Skin Smear revealed acid-fast bacilli of BI: 6+
|Figure 2: Histopathological picture of case 1 showing storifirm pattern consisting of lymphocytes, histiocytes and foamy macrophages. Wade fite stain showing heavy bacillary index|
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A 28-year-old female with 9-month amenorrhea presented with lesions over face, both hands, and legs since 3 months and complaint of epistaxis and nasal stuffiness. Lesions progressed to involve B/L limbs and back.
There was no history of fever, joint pain, or loss of chappals. There was no h/o contact with leprosy patients. No h/o any drug intake for leprosy.
On examination multiple papulo-nodular lesions with few nodular crusted lesions were present over forehead, earlobes, periorificial area ([Figure 1]; Case B), and both upper and lower extremities. Also few discrete hypopigmented patches over buttocks were observed. Both ulnar nerves were thickened. All sensations were slightly altered over both upper and lower extremities over glove and stocking distribution. Corneal and conjunctival sensations were normal. Motor examination was normal. All other routine investigations were normal.
On histopathological examination: Section shows thinning of epidermis with collection of macrophages foamy nodules in dermis. Clear grenz zone is evident. Skin adnexa and other dermal appendages are not seen. Heavy bacillary load was seen on Fite Faraco stain [Figure 3]. Split Skin Smear revealed acid-fast bacilli of BI: 6+
|Figure 3: Histopathological picture of case 2 showing clear Grenz zone with foamy macrophages and histiocytes. Wade fite stain showing heavy bacillary index|
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A 21-year-old male presented with papular lesions over face since 20 days. He had no complains of fever, epistaxis, or loss of chappals. On examination multiple shiny papulo-nodular lesions were found over forehead, ears, and cheeks ([Figure 1]; Case 3). Nasal stuffiness, congestion, and watering from eye present.
Bilateral ulnar nerve, greater auricular nerve, common peroneal nerve, anterior tibial nerve, posterior tibial nerve were thickened. Glove and stocking anesthesia present upto elbow and knee. Corneal and conjunctival sensations were normal. Motor examination was normal. All routine investigations were normal.
On histopathological examination: Section shows extensive cellular infiltration in dermis mainly composed of macrophages, lymphocytes, and plasma cells. There are clear Grenz zones below the flattened epidermis. Hematoxylin and eosin-stained sections showed classical histocytic Granulomas [Figure 4] with heavy bacillary load on Fite Faraco stain. Split Skin Smear revealed acid-fast bacilli of BI: 6+ [Figure 5].
|Figure 4: Histopathological picture of case 3 showing clear Grenz zone with spindle-shaped histiocytes. Wade fite stain showing heavy bacillary index|
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|Figure 5: Split Skin smear showing multiple acid-fast bacilli with Bacillary Index: 6|
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| Discussion|| |
Incidence of Histoid Leprosy has been reported to vary from 1% to 2% among total leprosy patients. 
There is male preponderance and the average age at diagnosis is between 21 and 40 years. 
The pathogenesis of this rare and unusual variant of leprosy still remains unresolved. Although histoid leprosy is considered to be variant of lepromatous leprosy there exists an enhanced immune response against Mycobacterium leprae in these patients compared with lepromatous leprosy with respect to both cell-mediated immunity and humoral immunity. Despite the presence of adequate number of macrophages it has been claimed that they lack the functional property to kill bacilli that exists in high numbers in histoid lesion. 
Clinically it is characterized by Multiple discrete shiny, smooth, painless, succulent, globular, protuberant, firm nodules, and papules, (skin to yellow brown in color) on normal appearing skin. The lesions are usually located on the posterior and lateral aspects of arms, buttocks, thighs, dorsum of hands. and on the lower part of the back and over the bony prominences, especially over the elbows and knees.  Ears may be unaffected. Histoid lesions have also been reported to present along the course of the peripheral nerve trunks and cutaneous nerves. Erythema nodosum rarely occurs in Histoid Hansen. 
Histoid leprosy clinically simulates xanthomas, neurofibroma, dermatofibroma, reticulohistiocytosis, or cutaneous metastasis. Each of them can be differentiated from histoid leprosy over the basis of its characteristic histopathology, the absence of lepra bacilli on slit skin smear and nerve thickening. 
On histopathological examination: Classical histopathologic findings include epidermal atrophy as a result of dermal expansion by the underlying leproma and an acellular band (Grenz zone) located immediately below the epidermis. The leproma consists of fusiform histiocytes arranged in a whorled, crisscross or storiform pattern containing acid-fast bacilli. 
The AFB is not found in globi formation, as they do not secrete any glial substance. They are longer than normal bacilli, uniform in length, and are arranged in parallel bundles along the long axis of histiocytes. Within the histiocytoid collections, there can also be islands of tiberculoid granulomas, which are called by wade as 'contaminating Tuberculoid bacilli'. 
There are three histological variants of histoid Hansen: Pure fusocellular, fusocellular with epitheloid component, and fusocellular with vacuolated cells. The third pattern is most commonly observed. 
FNAC is a simple cost effective method of investigation that is more useful in tuberculoid, lepromatous and histoid leprosy patients. 
Histoid leprosy is managed by Multi Drug Therapy similar to that in Lepromatous Leprosy.
| Conclusions|| |
All the above cases gave a short history of less than 3 months as well as presented within a period of three months. Our cases were unique in the sense that the patients were de novo cases of Histoid leprosy with no history of leprosy or ingestion of dapsone/multidrug therapy.
Because of its multibacillary character and despite its rarity, histoid leprosy poses a challenge to the leprosy eradication in India. A high index of suspicion is essential to continue the surveillance for new and relapse cases, rather than to wait for voluntary reporting. Histoid leprosy requires early detection and prompt drug therapy. These requirements should be made a priority in the national program against leprosy.
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Rita Vipul Vora
Department of Dermatology, Pramukhswami Medical College, Karamsad, Gujarat
Source of Support: None, Conflict of Interest: None
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]