A 61-year-old female presented to our outpatient department with an asymptomatic nodular lesion on the ventral aspect of the right forearm. She gives a history of a slow-growing nodule for the past 10 years. There were no similar lesions elsewhere in her body. On examination, a small 1 × 2 cm nodular lesion was seen on her right forearm [Figure 1]. The lesion was skin colored, firm, nonmobile, and non-tender on palpation. Button-hole sign was positive. Clinical differential diagnosis of Dermatofibroma and Solitary Neurofibroma were made.
Figure 1.
A small, firm, non-tender, 1 × 2 cm nodular lesion on right forearm
Dermoscopy (Dermlite DL4; 10×) of the lesion revealed a round circumscribed lesion with a central white scar-like area and peripheral halo of pigmentation [Figure 2a]. Fingerprint-like pigmentary lines and peripheral pigment network [Figure 2b] were also observed. Histopathology confirmed the diagnosis of Neurofibroma [Figures 3a and b].
Figure 2.
(a): Dermoscopic image showing central white scar like area (blue star) and peripheral halo of hyperpigmentation (yellow arrow) (b): Fingerprint-like pigmentary lines (green star) and peripheral pigment network (red triangle). (Contact polarised light dermoscopy; Dermlite DL4; 10×)
Figure 3.
(a): Photomicrograph showing a well-defined lesion in the dermis (yellow star) (H&E, 4×). (b) Spindle shaped cells (yellow arrow) arranged in whorls and fascicles with hyperchromatic, wavy, buckled nuclei (red arrow) (H&E, 40×)
Slow growing nodular lesions are difficult to diagnose clinically and histopathology usually aids in the diagnosis. In our patient, the dermoscopy features are suggestive of neurofibroma. Zaballos et al.[1] described multiple dermoscopic patterns for Dermatofibroma. The central scar-like area and peripheral pigment network can be seen in both conditions, but the fingerprint pattern along with above-mentioned findings is more suggestive of Neurofibroma. In another study, Duman et al.[2] described the above-mentioned findings in a series of cases of neurofibromas and defined the fingerprint pattern as brown parallel cord-like structures within the lesions. Fingerprint pattern can occur in other conditions like seborrheic keratosis, but in the background of other dermoscopic findings, it can help in identifying neurofibroma. This case is presented to highlight the dermoscopy findings in Solitary Neurofibroma and its role in differentiating from Dermatofibroma.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given her consent for her images and other clinical information to be reported in the journal. The patient understands that her names and initials will not be published and due efforts will be made to conceal her identity, but anonymity cannot be guaranteed.
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Conflicts of interest
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References
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