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Q1: What was the overall diagnosis?
Histiocytic necrotising lymphadenitis (Kikuchi Fujimoto disease)
Q2: What two unusual features are described in this case?
(1) The transient cutaneous anergy during the acute phase of the illness and (2) the migratory pattern of lymphadenopathy after a prolonged remission.
Histiocytic necrotising lymphadenitis or Kikuchi Fujimoto disease (KFD) is an uncommon, self limiting disease that primarily affects the cervical lymph nodes in young adults, mainly females. The aetiology seems unknown but an infective origin seems likely. Though the condition commonly affects patients of Asian descent, it has been more and more seen in other populations.1 2
KFD is a peculiar condition with broad morphological spectrum that can readily be mistaken for malignant lymphoma or lupus,3 thus an accurate distinction is crucial. Patients usually develop painless, often unilateral cervical lymphadenopathy in the context of fever, night sweats, arthralgia, rash, and asthenia.4 Painful lymphadenopathy may also develop.3 Generalised lymphadenopathy occurs infrequently3 and has recently been associated with human T cell leukaemia virus-1 infection.5The true nature of the lesion becomes evident on a lymph node biopsy rather than fine needle aspiration samples.6 Other infectious agents of possible relevance to pathogenesis include herpes virus 6, Epstein-Barr virus, cytomegalovirus, parvovirus B-19,Yersinia enterocolitica, and brucella species.7-12 KFD has been repeatedly linked with systemic lupus erythematosus3-13 and described in association with Hashimoto's thyroiditis,13 Sweet's syndrome,14 and Still's disease.15 The condition has a low recurrence rate of 3%–4% and rarely recurs after a prolonged remission. The acute phase of illness usually responds to bed rest and symptomatic treatment. The symptoms resolve within 1–4 months; however there have been cases that recurred3 or persisted as long as a year.4
In this case the migratory pattern of cervical lymphadenopathy, which was painful and tender at first presentation and painless on relapse, has led to a clinical diagnostic dilemma; a situation that would have not been settled without a second lymph node biopsy. Such a migratory characteristic, however, has not been specifically referred to in the previous literature. KFD should be considered in the differential diagnosis of any clinical setting with migratory lymphadenopathy. The repeatedly negative tuberculin test during acute illness was another issue of interest. Unless the cellular mediated immune reaction is stunted, the tuberculin test is expected to be positive in an Asian adult, even in the absence of active tuberculous disease. Thus, the negative reaction in our patient was likely to be a sign of transient cutaneous anergy possibly induced by the disease activity and recovered during remission. To the best of our knowledge this phenomenon was also not reported before, and is worthy of further study in future cases.
Histiocytic necrotising lymphadenitis (Kikuchi Fujimoto disease).