A 45 year old male had multiple hypoaesthetic mildly erythematous large plaques with elevated margins on trunk and extremities. His ulnar and lateral popliteal nerves on both sides were enlarged . The most probable diagnosis is:
Ans. is 'd' i.e. Borderline lepromatous leprosyRef: Pasricha 4th/e p 101-105; OP Ghai Paediatrics 5th/e p 208It's a very close diagnosisProblem in this question is that the skin lesions show the characteristics of tuberculoid leprosy and the nerve involvement shows the features of lepromatous leprosy.Characteristics of skin lesions in tuberculoid leprosyOne or few lesions Well defined borderLesions are erythematous and indurated plaquesThe plaque may be uniformly raised but sometimes it is annular and has raised margins.Lesions are HypoestheticCharacteristics of skin lesions in lepromatous leprosyNumerous, small, wide spread (involving, face, ear lobes)Bilaterally symmetricalIll defined, macules which gets nodularEarly involvement of face, nasal stuffiness, epistaxisSensations are unimpaired. They do not manifest the sensory loss which are so characteristic of tuberculoid leprosy.Now about the nerve involvement in the Tuberculoid typeNerve involvement is common in tuberculoid type.Nerve involvement begins early and progresses rapidly.The involvement is usually restricted to a single nerve which may either be small cutaneous nerve twig supplying cutaneous patch or it may be a large nerve trunk such as ulnar, median, radial, lateral popliteal, great auricular etc.Nerve involvement in the lepromatous typeNerves are infrequently involved but whenever involved the involvement tends to be B/L and symmetrical.So, now we can say that this case neither belongs to lepromatous leprosy (absence of characteristic lesions) nor to tuberculoid type (presence of B/L nerve involvement with numerous lesions)So it should be some dimorphous case i.e. either it is a case of Borderline Tuberculoid, Borderline lepromatous or midborderline (BB) leprosy. Mid borderline (BB) is not among the options. Note that Borderline leprosy is not same as Mid borderline (Borderline Borderline or BB). The term Borderline leprosy includes all the three -Borderline TuberculoidBorderline (B.B.)Borderline lepromatousSo we are left with the two options i.e. Borderline Tuberculoid and Borderline lepromatousThe following features favour the diagnosis of Borderline lepromatous leprosy.Multiple lesions with wide distribution in the body (Trunk and extremities are involved)B/L and symmetrical peripheral nerve enlargement.Though the presence of hypoaesthetic lesions with characteristic shape, erythematous plaques with raised margin is not typical of lepromatous, yet it can be seen in Borderline lepromatous.
Lepromatous leprosy
Borderline leprosy
Borderline tuberculoid leprosy
Borderline lepromatous leprosy
C. Mycobacteria