Relapse as histoid hansen: a rare presentation

To the Editor, A 27-year male presented with multiple lesions all over the body. The lesion started over the trunk and slowly progressed to involve the whole of the body over the past 2 weeks. Examination revealed multiple skin-colored papules mainly distributed over the trunk and bilateral upper limbs (Fig. 1). Some of the lesion progressed from small erosion to central ulceration. Nerve examination revealed thickened ulnar nerves more in right than left, more in right radial cutaneous nerves than left side while common peroneal nerves were thickened bilaterally, but nontender and non-nodular. There was distal loss of sensation to touch, pain, and temperature. Family history of tuberculoid leprosy was present in family member (father). Patient had received WHO recommended multi drug therapy (MDT) for lepromatous leprosy 5 years ago, following which he had no new lesionsFigure 1: Multiple skin-colored raised nodules present over trunk, some of them showing central ulceration (arrow).The hemogram, liver/renal function tests and chest radiography were normal. The skin smear from elbow for acid-fast bacilli showed a bacterial index of 5+[100–1000 bacilli per oil immersion field]. A skin punch biopsy was performed from the lesion at the back. Histopathological examination revealed a subepidermal grenz zone and whorled/storiform pattern of spindle-shaped histiocytes and a few foamy macrophages in the dermis (Fig. 2A, B). Fite-faraco stain revealed numerous acid-fast bacilli (Fig. 2C). Based on clinical and laboratory findings, histoid variant of lepromatous leprosy was diagnosed.Figure 2: A) − At low power (H&E-100×)- a dense lymphohistiocytic infiltrate throughout the dermis, interspersed with collagen fibers is seen (Hematoxylin & eosin, ×100). B) − At high power (H&E–400X) view showing foamy histiocytes (black arrow) along with spindled cells (green arrow) arranged in whorled pattern are seen (Hematoxylin & eosin, ×40). C) Oil Immersion − (1000×) − FiteFaraco stain highlights numerous acid fast lepra bacilli (arrow).Histoid leprosy (HL) is a rare and highly transmissible variant of lepromatous leprosy. It presents with erythematous brownish papules and nodules, with smooth or rarely umbilicated surface. Due to its unusual clinical features, it is a challenging diagnosis [1]. The pathogenesis of this variant is not fully understood. It is thought to be the result of multiple factors, combining genetic factors, abnormal immune response, and incomplete treatments. A hyperreactive response is thought to exist with increased cellular immunity due to the presence of necrosis and ulceration in some lesions, which is thought to be an effort to combat the Mycobacterium[2]. This may explain the ulceration observed in several nodules in our patient. HL usually occurs in multibacillary patients who have dapsone resistance, either primary or secondary which occurs particularly after dapsone monotherapy, but rarely de novo HL cases have been reported. Very few cases of relapse with HL have been reported after treatment with WHO recommended MDT. In 2000, Shaw et al. [3] reported three cases of relapse with HL after treatment with MDT. We hereby report a case of relapse with Histoid Hansen after 5 years of treatment with MDT. HL cases serve as an important infection reservoir and as a source of incident cases. Early diagnosis and management of these cases are important in this era of leprosy eradication [4]. The Differential diagnoses include keloids, dermatofibromas, disseminated reticulohistiocytosis, xanthomas, lobomycosis, skin metastases, neurofibromas, lymphomas, angiosarcoma [5]. It is important to recognize the atypical forms of Hansen disease to make the appropriate diagnosis and prescribe the correct treatment when required, to prevent the physical and psychological damage to the patients. Continual occurrence of these cases does not bode well for a country like India, where leprosy was eliminated as a public health problem in 2005. The main idea behind reporting this case of HL is not only to highlight this rare variant of lepromatous leprosy but also to bring to the notice of the authorities that the leprosy eradication program needs to be more effectively monitored in this region of Central India to prevent these cases in the future. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.