A Critical Clinicopathologic Evaluation of Nodular Lesions of Behçet's Disease

By Cuyan DEMiRKESEN and Cem MAT (Turkey)

Approximately 50 % of BD suffer from nodular lesions mostly located on the lower extremities. These nodules are painful, erythematous or violaceous in colour, measuring 1 to 8 cm. in diameter. They usually have an acute onset and heal with hyperpigmentation. The nodular lesions of BD are either superficial thrombophlebitis (ST) or erythema nodosum (EN)-like lesions. Although clinical differentiation of these nodules is not always easy, ST is frequently located on the medial side of the legs along the veins. ST is highly associated with deep vein thrombosis in BD. Reports about the nature of the EN like lesions in BD have been conflicting. Some authors indicated these lesions resembled EN both clinically and histologically, while others have reported findings of neutrophilic vasculitis. Therefore, we attempted to evaluate the histologic features of these lesions with control groups, composed of two common types of panniculitis, EN and nodular vasculitis (NV). Nodular lesions of 24 BD, 20 EN and 25 NV patients were compared according to a check list of histologic parameters by two observers in a masked manner. Biopsies of the nodular lesions of BD were obtained from volunteer patients who fulfilled the criteria for complete BD and attended a dedicated BD outpatient clinic in Cerrahpaşa Medical Faculty. Nodular lesions due to ST were excluded. Later on, the frequency of each histologic parameter for each disease category was compared by constructing frequency distribution graphs. Neutrophilic vasculitis was noted in 43 % of nodular lesions in BD. A neutrophil predominating inflammatory cell infiltrate was also a statistically important parameter in favour of BD when compared to NV and EN. This finding supports the earlier observations that EN-like lesions of BD are neutrophilic vascular reactions as papulopustular and pathergy lesions also are. Furthermore, it can be speculated that the lymphocyte predominating reaction in subcutis, noted in some BD, might be following a neutrophilic vascular reaction during the evaluation of these lesions, as proposed for pustular lesions of BD. Although the involvement of veins were seen more often in BD compared to EN and NV, the calibre of the involved vessels were mostly arterioles and venules. Necrosis, necrobiosis and granuloma formation in the subcutis was less frequent.

Although the diagnosis of BD is usually not established on the basis of histologic features detected in nodular lesions, we wanted to find out if there were any distinguishing features differing from EN and NV. Therefore, a paired t-test was done on frequencies of the 20 histological parameters taken as a group in BD vs NV, BD vs EN and NV vs EN. The histologic features detected in the nodular lesions of BD were akin to NV than EN. As a result, there was no significant difference between BD and NV. This, in turn suggests that the nodular lesions of BD may indeed be due to vasculitis as in NV. On the other hand, there was a significant difference between BD and EN (p=0.005). Presence of septal panniculitis, lymphocyte predominating infiltrate, absence of many vascular changes, as well as necrosis were features in favour of EN.

We now consider that the histologic features of the nodular lesions of BD have enough specificity to differentiate them from EN associated with other diseases.

  1. Selected References

  2. Nazzaro P. Cutaneous Manifestations of Behçet's Disease. Clinical and Histopathological Findings. Int Symp on Behçet's Disease, Rome, pp 15-41 (Karger, Basel/New York, 1966)
  3. Chun SI, Su WPD, Lee S, et al. Erythema nodosum-like lesions in Behçet's syndrome: a histopathologic study of 30 cases. J Cutan Pathol 1989; 16: 259-265.
  4. Jorizzo JL, Abernethy JL, White WL, et al. Mucocutaneous criteria for the diagnosis of Behçet's disease: An analysis of clinicopathologic data from multiple international centres. J Am Acad Dermatol 1995; 32: 968-976.
  5. Demirkesen C, et al. Clinicopathologic Evaluation of Nodular Lesions of Behçet's Disease. Am J Clin Pathol (in print)

[Previous] [Next]