Diagnosis and comments: Birt-Hogg-Dubé syndrome

ARTICLE

Diagnosis and comments: Birt-Hogg-Dubé syndrome

Our patient had skin-colored, dome-shaped nodules which were histopathologically confirmed to be a typical trichodiscoma (Fig. 2a, b). One of the excised lesions showed some of the changes of fibrofolliculoma (Fig. 2c). No other family members of our patient were examined but, based on the history, two brothers of the patient were suspected to have the same disease. Taken together, our case represents an example of the Birt-Hogg-Dubé syndrome [1], an autosomal dominant condition, which is a triad of cutaneous lesions consisting of fibrofolliculomas, trichodiscomas and acrochordons. The connective tissue component of the pilar apparatus gives rise to three different forms of proliferative disorders, namely perifollicular fibroma, fibrofolliculoma and trichodiscoma. Trichodiscoma, so far observed only in multiple form, has been considered to be a fibrovascular hamartoma of the dermal component of the hair disc [2]. Multiple trichodiscomas may be observed either in a pure form or in association with perifollicular fibromas or fibrofolliculomas. Although the histological characteristics of trichodiscoma, its constant topographical relation to hair follicles and complex composition of mucinous and richly vascularized fibrous tissue, are similar to those of the hair disc [3], the histogenesis of trichodiscoma has been under debate [4]. More recently, these three hamartomas have been classified into one category, namely follicular fibroma, which is regarded as a proliferative disorder of the fibrous sheath or mesenchymal papilla of the hair follicle [5]. And tichodiscomas, fibrofolliculomas and acrochordons in Birt-Hogg-Dubé syndrome have been considered to be variations of a single pathological process [6]. Colonic polyposis or colonic cancer has been reportedly associated with Birt-Hogg-Dubé syndrome or with multiple perifollicular fibromas in several cases [7-9]. Although our patient and his brother had colonic polyps, those lesions could be an age-related change. It is possible that the diagnosis of asymptomatic intestinal disease was missed in some previously reported cases and it is necessary to look for internal lesions in this syndrome. Recently three kindreds in whom renal neoplasms and Birt-Hogg-Dubé syndrome appeared together was reported [10], however, it still remains controversial whether or not these hamartomas are in reality paraneoplastic dermatoses.

Article accepted on 21/3/00

REFERENCES

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