Familial Multiple Discoid Fibromas (FMDF) is an extremely rare genodermatosis (OMIM 190340) presenting clinically with multiple, skin-coloured, dome-shaped papules located mainly on the face, neck, trunk and especially on pinna.1 Although FMDF resembles Birt-Hogg-Dubé (BHD) syndrome (OMIM 135150) clinically, it has been recognized as a distinct entity based on its specific clinical characteristics and genetic profile.1,2

The index patient is a 25-year-old man who presented with multiple asymptomatic papules on his face, ears, trunk, and extremities. The lesions had begun in early adolescence and increased in number and size since then. Dermatological examination revealed multiple, firm, skin-coloured small papules on his central face, most prominently on the pinna (Fig. 1), trunk, and lower extremities. Histopathological examination revealed well-circumscribed discoid fibrovascular proliferation compatible with discoid fibroma (Fig. 2). No mutations were detected in genetic analysis of FLCN, PTEN, TSC1 and TSC2 loci. Radiological imaging of lungs, kidneys and brain was normal. When the family of the patient was evaluated, there was no parental consanguinity; the patient had only one brother. Similar multiple papules on the central face and the pinnae (Fig. 3) of his mother (47-year-old), and fewer papules on the face, pinnae and the neck of his younger brother (22-year-old) were detected. Their lesions had also begun in early adolescence. Histopathologic, genetic, and radiologic results of his mother and brother were similar.

Figure 1.

Discoid fibromas in Patient nº 1. Multiple skin-coloured small papules on the pinna.

Figure 2.

Histopathological examination of discoid fibroma. Well-circumscribed discoid fibrovascular proliferation (Hematoxylin & eosin, ×40).

Figure 3.

Discoid fibromas in his mother. Multiple skin-coloured papules on the pinna.

The literature review and patient characteristics are summarized in Table 1. Clinical differential diagnoses of multiple skin-coloured papules include BHD syndrome, multiple fibrofolliculomas, trichoepitheliomas, tuberous sclerosis complex, Cowden syndrome, and Brooke-Spiegler syndrome.1–4 FMDF differs from these conditions by its characteristic early age of onset, preferential involvement of the pinna, distinct histopathology compatible with discoid fibroma, absence of systemic manifestations, and its different genetic profile.

Genetically, FMDF is defined by the absence of FLCN mutations, though a recent study suggests a possible link with a locus on chromosome 5 including the FNIP1 gene.4 Although it is not exactly settled, autosomal-dominant inheritance has been described for most of the patients. Also, in the family we reported, the fact that the mother and both of her male children were affected, despite no affected individuals in the ancestors, suggests that a de novo mutation in the mother was inherited in an autosomal dominant manner. The observation that the number and size of discoid fibromas were highest in the oldest patient ‒ the mother ‒ and lowest in the youngest patient ‒ the brother ‒ suggests that the disease burden accumulates progressively over time.

Regarding treatment, surgical destructive methods may be used in the treatment of discoid fibromas. Topical rapamycin was reported to be beneficial in a case report.3 We performed electrosurgery for the lesions on the pinnae in our patients. However, during follow-up, the lesions showed a tendency to recur.

In conclusion, our findings emphasize that clinical recognition and careful genetic characterization remain key challenges in FMDF. A better understanding of its genetic background could improve diagnosis, counseling, and therapeutic strategies for this rare entity.