Congenital multiple clustered dermatofibroma: dermatoscopic findings

ARTICLE

Auteur(s) : Hatice Sanli¹, Bengu Nisa Akay¹, Aylin Okcu Heper²

¹Department of Dermatology, Ankara University, School of Medicine, Dermatoloji Anabilim Dalı, İbni Sina Hastanesi, Samanpazarı-Ankara, Turkey
²Department of Pathology, Ankara University, School of Medicine, Ankara, Turkey

Dermatofibromas clustered in one anatomical area, defined as multiple clustered dermatofibromas (MCD), are a strikingly rare entity [1-3]. MCD usually develop during adolescence or early adult life. Congenital MCD is extremely rare [2]. We present an additional case of congenital MCD, together with its dermatoscopic findings.

A 19-year-old boy presented with multiple, pruritic, reddish-brown papules on his left lumbar region. He reported lesional onset at birth with gradual enlargement after puberty, associated with the development of multiple new lesions. He reported no allergies, surgery or trauma. Examination of the left lumbar region showed reddish brown, clustered, non-scaling, firm papules ranging in size from 4 to 9 mm, arranged in a linear pattern (figure 1A). Some papules demonstrated dimpling on lateral compression. Dermatoscopic examination showed a pigment network all over the clustered papules (figure 1B). Dermatopathological examination revealed a dermal tumor just beneath the hyperplastic and hyperpigmented epidermis, extending from the superficial dermis to the deep reticular dermis and largely composed of interlacing short fascicles of spindle cells in a storiform arrangement. Tumor cells showed factor XIIIa positivity and CD34 negativity. A diagnosis of dermatofibroma was made.

Dermatofibroma is a common cutaneous condition, probably of inflammatory origin, with diverse clinical variants including giant (> 5 cm in diameter), atrophic, atypical polipoid and dermatofibroma with satellites. MCD is a very rare entity that corresponds to numerous dermatofibromas appearing on a single region of the anatomy, mainly on the lower half of the body [1-3]. In all reported cases, the lesions seem to develop during adolescence or early adult life. To our knowledge, there is only one report of MCD occurring at birth [2]. In that case the lesions extended to involve a broad zone on the left hip, gluteal region and upper thigh. The present case is the second congenital MCD arranged in a linear pattern to be described.

MCD can be eruptive or new lesions can develop over months to years. Papules may arrange in a coalescent fashion to form a large plaque or in a linear configuration. The pathogenesis is still unknown. Triggering factors such as insect bites, jelly fish bites, superficial venous thrombosis and surgery have been implicated in some cases [1, 3]. However development of MCD appears to be unassociated with an inciting event or immune dysfunction.

Dermatoscopy, which is a non-invasive diagnostic technique, was used to evaluate the pigmentary changes of the lesion. Dermatoscopy revealed pigment network all over the clustered lesions. In the algorithm for the diagnosis of pigmented skin lesions by dermatoscopy, the presence of pigment network usually indicates a melanocytic skin lesion but it can also be found in a variety of non-melanocytic lesions, including dermatofibroma, solar lentigo, ink spot lentigo, accessory nipple and CM [4-6]. In the clinical and dermatoscopic differential diagnosis [6], CM was considered more likely due to the congenital and pruritic origin of the lesions. The diagnosis of CM is confirmed by a dermal infiltrate composed of mast cells that can be recognized on skin sections stained with HE. The hyperpigmentation of CM can be explained by an increase in melanin in basal keratinocytes. Here the pigment network seen in dermatoscopy is a result of an increase in melanin in the hyperplastic epidermis. The papule came into being mostly by virtue of the fibroplasia in the upper half of the dermis, and the smooth surface is a reflection of the stratum corneum being normal.

In conclusion, we present the dermatoscopic findings in an unusual case of MCD. The presence of the lesions in our patient since birth indicated the possibility of the congenital character of this fibroblastic tumour.

Acknowledgements

REFERENCES

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