|Year : 2013 | Volume
| Issue : 1 | Page : 29-31
Histoid leprosy in the era of elimination
Sukumar Dandekeri, Hyacinth Peter Pinto, Ramesh M Bhat, MK Srinath
Department of Dermatology, Father Muller Medical College and Hospital, Kankanady, Mangalore, India
|Date of Web Publication||20-May-2013|
Department of Dermatology, Father Muller Medical College and Hospital, Kankanady, Mangalore - 575 002
Source of Support: None, Conflict of Interest: None
Histoid leprosy is a variant of Lepromatous leprosy believed to occur due to a mutant strain of leprosy bacillus called as Histoid Bacillus. It was first described by Wade in 1960 in patients from Phillipines. It occurs in patients relapsing after Dapsone monotherapy, in the presence of Dapsone resistance or at times denovo, presenting with lesions mainly over bony prominences. Herein, we present a case of a 37 year old male who presented with skin coloured raised lesions mainly over the trunk, chest, neck and ears in contrast to its usual site of presentation, associated with tingling sensation over the hands and feet. A histopathological examination of the skin lesion was ordered which revealed sheets of histiocytes and lepra bacilli on hematoxylin and eosin and acid fast staining. On correlating the clinical and histopathological findings we came to a diagnosis of Histoid leprosy. The patient was promptly treated with MB-MDT and followed up.
Keywords: Multibacillary multidrug therapy, Elimination
|How to cite this article:|
Dandekeri S, Pinto HP, Bhat RM, Srinath M K. Histoid leprosy in the era of elimination. Muller J Med Sci Res 2013;4:29-31
| Introduction|| |
Histoid leprosy is a variant of lepromatous leprosy believed to occur due to a mutant strain of leprosy bacillus called as histoid bacillus. It was first described by Wade in 1960 in patients from Philippines. It occurs in patients relapsing after dapsone monotherapy, in the presence of dapsone resistance or at times de novo, presenting with lesions mainly over the bony prominences.  Herein, we present a case of a 37-year-old male who presented with skin colored raised lesions mainly over the trunk, chest and neck, in contrast to its usual site of presentation mainly over the extremities and bony prominences with associated tingling sensation over the hands and feet.
| Case Report|| |
A 37-year-old male patient presented to the skin out-patient department with chief complaints of asymptomatic skin colored raised lesions over the body of 3 months duration. Patient was apparently alright 3 months ago when he noticed small skin colored lesion over his abdomen, which later increased in number and extent to involve upper chest and back in a span of 6 weeks. He also experienced tingling sensation over hands and feet and there was no history of slippage of footwear. There was no history of similar complaints in the family and no history suggestive of difficulty in performing fine skilled activity or constitutional symptoms.
On examination, multiple skin colored papules and well demarcated nodules of varying sizes and shape distributed symmetrically over neck and trunk. Few firm, skin colored, dome shaped papules with overlying shiny skin and smooth surface present over the chest [Figure 1], [Figure 2] and [Figure 3]. Sensations over the lesions was not impaired, however, percerption of touch, temperature and pain over bilateral forearms, hands, legs and feet was impaired. Ear lobes showed nodular infiltration.
|Figure 1: Multiple, well-defined, erythematous nodules and papules present over the abdomen and chest|
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|Figure 3: Multiple, well-defined, erythematous nodules and papules present over the back and neck|
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On histopathological examination of one of the lesions, epidermis was found to be thinned out, with flattened rete ridges. Dermis showed diffuse collection of foamy macrophages and spindle shaped cells (histiocytes) separated from the epidermis by clear Grenz zone [Figure 4] Fite stain was positive [Figure 5]. Slit skin smear was positive with a bacterial index of 3.50. Patient was started on multibacillary multidrug therapy (MBMDT) and asked to come for follow-up regularly.
|Figure 4: Dermis showed diffuse collection of foamy macrophages and spindle shaped cells (histiocytes)|
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|Figure 5: Fite stain- positive, showing acid- fast bacilli arranged in clusters|
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| Discussion|| |
The term "histoid" was introduced because the condition resembles a tumor developing from spindle-shaped histiocytic elements. It closely resembles dermatofibroma and other histiocytic and fibrotic skin tumors.  Histoid Hansen's also goes by the synonyms - histoid nodules, Mycobacterium leprae histiocytoma (cutis) and Leprous histiocytoma. It is considered by some as a variant of lepromatous leprosy and by others as a distinct clinical entity. This can also be seen in patients with borderline lepromatous and indeterminate leprosy.
In India, its incidence among leprosy patients has been estimated to be between 2.79% and 3.60%. It is not uncommon in South India. There is a male preponderance, and the average age at diagnosis is between 21 and 40 years.  The incidence of histoid leprosy was found by Singh et al. to be 8.7% among lepromatous leprosy and 1.2% among all leprosy patient.  Histoid leprosy clinically simulates xanthomas, neurofibroma, dermatofibroma, reticulohistiocytosis, or cutaneous metastasis. Each of them can be differentiated from the histoid leprosy on the basis of its characteristic histopathology, the absence of lepra bacilli on slit skin smear and nerve thickening. 
Occurs in lepromatous patients relapsing after dapsone monotherapy, in the presence of dapsone resistance or at times, de novo has also been reported in patients in whom relapse occurred in the presence of supervised monthly dose of MDT and in patients without any treatment.  Ebenezer et al. described a patient who developed Histoid Hansens after 7 years of supervised MDT. 
Clinically, it is characterized by multiple, smooth, painless, firm skin colored to yellow brown nodules on normal appearing skin. The nodules may involve face, back, limbs and bony prominences, as well as mucous membranes in severely affected patients. Ears may be unaffected. Histoid lesions have also been reported to present along the course of the peripheral nerve trunks and cutaneous nerves.  Classical histopathological findings include epidermal atrophy as a result of dermal expansion of the underlying leproma and a Grenz zone located immediately below the epidermis.  The leproma consists of fusiform histiocytes arranged in a tangled or storiform pattern containing acid fast bacilli. There are three histologic variants of Histoid Hansens: Pure fusocellular, fusocellular with epitheloid component, and fusocellular with vacuolated cells. The third pattern is most commonly observed.  Histoid leprosy is managed by initially giving the range of motion therapy, with Rifampicin 600 mg, Ofloxacin 400 mg, and Minocycline 200 mg, which is followed by WHO MBMDT therapy. 
| Conclusion|| |
We present this case as, even though we consider ourselves to be in the era of elimination of leprosy, we happened to come across such a case of histoid leprosy. Furthermore, our patient presented with lesions mainly over the trunk in contrast to its usual site, i.e., extremities and bony prominences. It is important to have a high index of suspicion while approaching cases such as these and advocating the importance of adequate and appropriate medications to pave the path toward the eradication of leprosy in India.
| References|| |
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]