Familial multiple discoid fibromas: unique histological features and therapeutic response to topical rapamycin

Abstract

Familial multiple discoid fibromas is a rare genodermatosis that bears some resemblance to Birt-Hogg-Dubé syndrome but is not associated with mutations in the folliculin (FLCN) gene or systemic manifestations. It is characterized by the development of papules over the face and pinnae early in life. Histological findings are of fibrovascular tumours adjacent to hair follicles without features characteristic of fibrofolliculomas, which have recently been termed discoid fibromas. We present siblings with multiple papules over the face and pinnae that developed in childhood. Histological specimens from both siblings demonstrated discoid fibromas, but with some lesions exhibiting an unusual keloidal-like pattern with thick hyalinized collagen fibres surrounded by plump spindle and histiocyte-like cells. FLCN gene mutations were not found. We report on clinical improvement with topical rapamycin solution (1 mg mL(-1)) applied daily to the face for 4 months. Therapeutic response to topical rapamycin may provide a clue to the underlying genetic basis of this condition.

Familial Multiple Trichodiscomas: Case Report and Concise Review

“…The incidence of familial multiple trichodiscomas is unknown [ 1 , 6 ]. It is suspected that many cases prior to the availability of FLCN gene testing may have been misdiagnosed as Birt-Hogg-Dubé syndrome.…”

“…Autosomal-dominant inheritance has been described for a majority of the patients [ 1 ]. However, Wee, et al also suggest an autosomal-recessive pattern of inheritance or germline mosaicism [ 6 ].…”

“…Hence, since the trichodiscomas of familial multiple trichodiscoma do not transition into fibrofolliculomas after deeper sectioning of the biopsy, they represent a distinct pathology separate from that observed in the trichodiscomas of Birt-Hogg-Dubé syndrome [ 1 ]. Therefore, in order to avoid further confusion with the trichodiscomas of Birt-Hogg-Dubé syndrome, the original coiners of familial multiple trichodiscomas have attempted to rename the familial multiple trichodiscoma-associated trichodiscomas as discoid fibromas and the disease entity as familial multiple discoid fibromas [ 1 , 6 ].…”

Improvement of Facial Hamartomas by Continuous Wave CO2 Laser Resurfacing in Birt-Hogg-Dube Syndrome

“…The facial hamartomas generally appear in the 3rd decade of life and in more than 80% of patients with Birt-Hogg-Dube by the 5th decade [1].Treatment of the facial hamartomas has been attempted by shave, medications, curettage, electrocautery and skin resurfacing by a variety of methods, including laser. The majority of published literature centres on description of the lesions instead of treatment [2][3][4]. The facial lesions are known to recur even after successful treatment [5].Fractional continuous wave CO 2 laser is a novel CO 2 utilizing true ablation along with maximal thermal effects for skin tightening.…”

“…Treatment of the facial hamartomas has been attempted by shave, medications, curettage, electrocautery and skin resurfacing by a variety of methods, including laser. The majority of published literature centres on description of the lesions instead of treatment [2][3][4]. The facial lesions are known to recur even after successful treatment [5].…”