Histoid Leprosy is a well-recognized clinical entity, characterized by cutaneous and/or subcutaneous nodules and plaques present over an apparently normal skin with unique histopathology and characteristic bacterial morphology.1, 2 It usually manifests itself in patients on diaminodiphenyl sulfone (DDS) for a long time, reflecting initial improvement followed by a relapse.3–9 Irregular10–12 and inadequate13 therapy may further compound its occurrence. Some workers5, 10,14–17 believe that it is due to the development of drug resistance to DDS, while others9, 10,14 postulate that mutant organisms, that emerge from a predominantly sulfone susceptible bacterial population, may be responsible. Treatment with DDS creates a selective environment by killing or at least inhibiting, multiplication of drug sensitive organisms, thus allowing the growth of the drug resistant, ‘histoid’ bacilli.6, 10, 12, 18–24 Its de novo occurrence may make it difficult to diagnose. So, a high degree of suspicion is imperative in such cases.
Apart from its occurrence in lepromatous leprosy, histoid may occasionally be seen in borderline,7, 10, 18, 25–28 and indeterminate leprosy.29
Ever since the description of histoid leprosy by Wade,30, 31 an emphasis was laid on its retrospective histological diagnosis,31 which was subsequently reaffirmed.5, 6, 19 However, in Sehgal and Srivastava's experience,1, 32 it can be diagnosed with certainly, relying on its prospective clinical features, a fact appreciated and duly reiterated by Professor Samuel L Moschella, while reviewing a scintillating report on the entity in the Year Book of Dermatology33 1988.
The term histoid was originally coined in the year 1960 by Wade,30 as a historical concept of bacillary rich leproma composed of spindle shaped cells, along with an absence of globus formation, so conspicuous, in the ordinary leproma, and which exhibits, a fibromatoid, tendency in chronic form. Since then many reports,3–6, 10–14, 25, 31, 32, 34 have documented this entity. Although some authors,1, 4, 26 regard it as a distinct clinicopathological entity, yet, others3–6, 10, 12–15, 18, 19, 25 consider it as a variant of lepromatous leprosy. The entity initially was recorded in multibacillary patients, on irregular, and inadequate dapsone (mono) therapy, but later de novo cases were also encountered.1, 32
The ultrastructure of these lesions, was studied, for the first time, by Job et al,34 describing its prime cell type as a histiocytes, behaving both as a macrophage and fibroblast. Later, Ridley and Liu et al,26, 35 also documented its ultra-structure.
Despite sporadic reporting, histoid leprosy was not given a thought, until Sehgal et al36 in the year 1985 documented for the first time the immunological profile of this intriguing and exquisite expression of multibacillary leprosy. In the subsequent years, Sehgal and Srivastava,32 advanced dialogs, stressing prospective clinical diagnosis, in their two authoritative, investigative reports.1, 32 The latter, in particular, brought to light certain important revelations, which led to more lucid understanding of this enigmatic disease.
After these revelations, the research workers across the globe developed interest in this enigmatic, unique expression, the histoid leprosy, of a very common entity of the developing countries, and several reports37–49 started pouring from different parts of the world. A high degree of suspicion brought to book several more cases of histoid leprosy hither to undiagnosed.50–54
Sehgal and Srivastava32, 36, 55 based on these extensive studies on the entity postulated that histoid should occupy a separate position on the continuous leprosy spectrum besides lepromatous leprosy.
Histoid leprosy is an expression of multibacillary leprosy, characterized by the occurrence of nodules and/or plaques in the skin or the subcutaneous tissues. Well-demarcated, cutaneous nodule is its cardinal feature. They are present over an apparently normal skin.1, 18 The reactional episodes are seldom recorded in this entity.30, 31 However, they are recognized by their distinct bacteriology and histopathology.31
Cytodiagnosis using fine needle aspiration of such nodules or plaques can be an instant tool for diagnosis of histoid leprosy.37
Histoid is a universally accepted nomenclature, the credit for which goes to Wade.31 Some workers,12 however, prefer the name ‘histoid nodules’ to histoid leprosy, while others use Mycobacterium leprae histiocytoma (cutis)2 or leprous histiocytoma.56 Prior to Wade's description,30, 31 the entity was relatively unknown, although, Mitsuda57 had commented on a similar histological picture,5 earlier.
Jonquire27 called such nodules as young lepromas or pseudofibromatous lepromas before Wade31 assigned the name ‘histoid lepromatous leprosy’. Such cases were not so uncommon in the pre-sulfone era, and had been designated as ‘florida lepromatous leprosy’, ‘advanced nodular lepromatous leprosy’, and formed a part of the ever-obliging group of nodular lepromatous leprosy.18
An interesting record of a 70 years old Italian man with a nodular skin eruption which was diagnosed after much of futile academic efforts, prompted the authors to label it as ‘pseudotumour leprosy’.58
While coining the term ‘histoid leprosy’, Wade31 had considered, only its histopathological features for making a retrospective diagnosis. However, after an extensive experience of these patients, Sehgal and Srivastava,32 advanced several prospective guidelines for delineating this as a distinct clinical entity. They stressed that it should occupy a separate position besides lepromatous leprosy on the leprosy spectrum.
- Sehgal VN, Srivastava G. Status of histoid leprosy—a clinical, bacteriological, histopathological, and immunological appraisal. J Dermatol (Tokyo). 1987;14:38-42.
- Sehgal VN, Srivastava G, Beohar PC. Histoid leprosy—a histopathological reappraisal. Acta Leprologica. 1987; 5:125-131.
- Wade HW. The histoid variety of lepromatous leprosy. Int J Lepr. 1963;31:129-142.
- Price EW, Fitzhebert H. Histoid variety of lepromatous leprosy. Int J Lepr. 1966;34:367-374.
- Mansfield R. Histoid leprosy. Arch Pathol. 1969;87:580-585.
- Chaudhary DS, Chaudhary M, Armah K. Histoid variety of lepromatous leprosy. Lepr Rev. 1971;42:203-207.
- Melamed AJ, Manzi RO, Melamed M. Leproma interpolar dimorfa con estructuras histoidas (Wade). Leprologica. 1964;2:86-90. Abstract, Int J Lepr. 1967; 35:228.
- Languillon J, Rucher H, Sarrat H. A case of nodular lepromatous leprosy with fusiform cells—Wade's histoid variety. Bull Soc Med Afr Noire Lang Fr. 1974;19:206-209.
- Moschella SL, Pillsbury DM, Hurley J. Dermatology 1st ed. Philadelphia: WB Saunders Company. 1975;820.
- Rodriguez JN. The histoid leproma, its characteristics and significance. Int J Lepr. 1969;37:1-21.
- Malik R, Khandpur R, Chandra K, et al. A clinicopathological study of 244 cases of leprosy with special reference to histoid variety. Lepr India. 1977;49:400-405.
- Saul A, Novales J, Wong A. Leprahistoide (Wade)—Commentarious a proposito de un caso. Rev Leprol. 1976;10:486-90. Abstract, Int J Lepr. 1977;45:309.
- Ramos—Caro FA. Histoid lepromas. Cutis. 1982;30:108-109.
- Desikan KV, Iyer CG. Histoid variety of lepromatous leprosy. A histopathologic study. Int J Lepr. 1972;40:149-156.
- Bopp C, Bakos L. The histoid variety of lepromatous leprosy. Arch Dermatol Forsch. 1975;252:1-10.
- Bopp C, Bernardi C, Bakos L. The histoid variety of lepromatous leprosy. Med Cutan lber Lat Am. 1975;3:29-36.
- Ramanujam K, Arunthani S, Chacko CJ, et al. ‘Neural histoid’—histoid leproma in peripheral nerve; a case report. Lepr Rev. 1984;55:63-68.
- Ramanujam K, Ramu G. Wade's histoid lepromatous leprosy. Report of a clinical study. Lepr Ind. 1969;41:293-297.
- Kroll JJ, Shapiro L. The histoid variety of lepromatous leprosy. Int J Dermatol. 1973;12:74-78.
- Languillon J, Rucher H, Sarrat H. Nodular lepromatous leprosy with spindle-shaped cells in Africa. The ‘histoid’ leprosy of Wade. Med Trop. 1973;33:595-604. Abstract, Int J Lepr. 1975;43:173.
- Rampure AM, Bhargava MK. Wades’ histoid lepromatous leprosy. Indian J Pathol Micro. 1979;22:89-92.
- Ridley MJ, Ridley DS. Histoid leprosy. An ultrastructural observation. Int J Lepr Mycobact Dis. 1980;48:135-139.
- Singh VV, Singh G, Kaur P, et al. Histoid leprosy in Varanasi. Ind J Dermatol Venereol Leprol. 1983;49:160-161.
- Bhutani LK, Bedi TR, Malhotra YK, et al. Histoid leprosy in north India. Int J Lepr Mycobact Dis. 1974;42:174-181.
- Liu J, Kong QY, Ye GY, et al. Observations on ultra-structure of histoid leproma. Int J Lepr Mycobact Dis. 1982;50:471-476.
- Jonquires EDL. Leproma histoid (Wade). Leprologica. 1964;2:98-106. Abstract, Int J Lepr. 1967;35:227-228.
- Barton RP, Hogerzeil LM, McDougall AC. Borderline tuberculoid leprosy with a ‘lepromatous’ nodule of the nasal mucosa; a case report. Lepr Ind. 1980;52:114-118.
- Ramanujam K, Ramu G. Histoid transformation from unstable forms of leprosy. Abstract of Congress Papers 17/335. Int J Lepr. 1973;41: 685.
- Wade HW. The histoid leproma. Abstract. Int J Lepr. 1960;28:469.
- Wade HW. The histoid variety of lepromatous leprosy. Int J Lepr. 1963;31:129-142.
- Sehgal VN, Srivastava G. Histoid leprosy—a prospective diagnostic study in 38 patients. Dermatologica. 1988;177:212-217.
- Sehgal VN, Srivastava G. Status of histoid leprosy—a clinical, bacteriological, histopathological, and immunological appraisal. In the year Book of Dermatology. Year Book Medical Publishers. 1988.
- Job CK, Chacko CJ, Taylor PM. Electronmicroscopic study of histoid leprosy with special reference to its histogenesis. Lepr India. 1977;49: 467-471.
- Liu JH, Liw Z, Yang LH, et al. Further observations on ultrastructure of histoid leprosy. Abstract of XII International Leprosy Congress Papers. Int J Lepr. 1984;52:755-756.
- Bhake AS, Desikan KV, Jajoo UN. Cytodiagnosis of histoid leprosy. Lepr Rev. 2001;72:78-82.
- Shaw IN, Ebenezer G, Rao GS, et al. Relapse as histoid leprosy after receiving multidrug therapy (MDT); a report of three cases. Int J Lepr Other Mycobact Dis. 2000;68:272-276.
- Kalla G, Purohit S, Vyas MC. Histoid, a clinical variant of multibacillary leprosy: report from so-called nonendemic areas. Int J Lepr Other Mycobact Dis. 2000;68:267-271.
- Krishna KK. Histoid leprosy; report of three cases. Int J Lepr Other Mycobact Dis. 1999;67:174-176.
- Ebenezer GJ, Barkataki A, Job CK. Leprosy relapse presenting in a histoid form after multidrug therapy. Br J Dermatol. 1999;140:759-760.
- Cuevas-Santos J, Contreras F, McNutt NS. Multibacillary leprosy: lesions with macrophages positive for S100 protein and dendritic cells positive for Factor 13a. J Cutan Pathol. 1998;25:530-537.
- Ramesh V, Misra RS, Kachhawa D, et al. Giant lesions in histoid leprosy. Int J Lepr Other Mycobact Dis. 1998;66:232-234.
- Kontochristopoulos GJ, Aroni K, Panteleos DN, et al. Immunohistochemistry in histoid leprosy. Int J Dermatol. 1995;34: 777-781.
- Corcos MG, Corcos CD. “Tuberculoid contamination” in histoid hanseniasis. Int J Lepr Other Mycobact Dis. 1993;61:471-472.
- Perrin C, Michiels JF, Bernard E, et al. Cutaneous spindle-cell pseudotumors due to Mycobacterium gordone and Leishmania. Am J Dermatopathol. 1993;15:553-558.
- Fiallo P, Nunzi E, Betto P, et al. Histoid leprosy in early macular lepromatous leprosy; incidental finding or sign of augmented local immunity? Int J Lepr Other Mycobact Dis. 1993;61:471-472.
- Pavithran K. Giant histoid tumor. Int J Lepr Other Mycobact Dis. 1992; 60: 274-276.
- LeBoit PE. Dermatopathologic findings in patients infected with HIV. Dermatol Clin. 1992;10:59-71.
- Aggarwal K, Jain VK, Dayal S. Histoid leprosy with filariasis. Ind J Dermatol Venereol Leprol. 2002;68:345-346.
- Thappa DM, Karthikeyian K, Vijaykumar M, et al. Histoid leprosy masquerading as tuberous xanthomas. Indian J Lepr. 2001; 73:353-358.
- Patil V, Inamdar A, Athanikar SB, et al. Histoid leprosy—an unusual presentation. Indian J Lepr. 2000;72:491-493.
- Pavithran K. Histoid nodules of leprosy on the lip. Int J Lepr Other Mycobact Dis. 1997;65:374-375.
- Sehgal VN. Clinical Leprosy. 4th ed. New Delhi. Jaypee Brothers Medical Publishers, New Delhi. 2004:187.
- Misra RC. Leprous histiocytoma. Lepr India. 1980;52:582-585.
- Mitsuda K. The significance of the vacuole in the Virchow lepra cell and the distribution of lepra cells in certain organs. Int J Lepr. 1936; 4:491-508.
- Triscott JA, Nappi O, Ferrara G, et al. “Pseudoneoplastic” leprosy. Leprosy revisited. Am J Dermatopathol. 1995;17:297-302.