Cutaneous mastocytoma is a form of mastocytosis that usually affects newborns and children, representing an uncommon finding in adults [ 1 ] . Clinically, it presents with up to 3 yellowish, brown, or red nodular lesions mainly located on the trunk and extremities [ 1 ] . The most common dermoscopic feature is a yellow-orange blot pattern [ 1 ] .
We report the unusual case of an adult-onset facial cutaneous mastocytoma, arising on the forehead, and describe a new dermoscopic pattern.
A 36-year-old woman came to our dermatology department for the presence of an asymptomatic erythematous plaque on the forehead, of two-month-duration ( Figure 1 ). The patient was in good health and did not refer systemic symptoms; her medical and pharmacological history was unremarkable. Dermoscopic evaluation revealed an irregular vascular pattern characterized by irregular linear vessels, some of which serpiginous, of steady caliber, on a pink-red background and perifollicular scar-like white areas ( Figure 2 ). Incisional biopsy displayed the presence of a diffuse and homogeneous pan-dermal infiltrate of mast cells, with some perivascular and peri-adnexal lymphocytes and plasma cells in the upper dermis. To rule out systemic mastocytosis, routine blood tests as well as serum tryptase (sT) were performed resulting unremarkable. Based on clinical, dermoscopic and histologic findings along with normal sT levels and absence of systemic involvement, a diagnosis of cutaneous mastocytoma was made. The patient was started on topical tacrolimus with progressive subsiding of clinical manifestations.
Figure 1 .
Clinical aspect of facial cutaneous mastocytoma: an erythematous plaque of the forehead.
Figure 2 .
Dermoscopy of facial cutaneous mastocytoma: irregular vascular pattern with linear vessels, some of which serpiginous, showing steady caliber; pink-red background; perifollicular scar-like white areas.
Adult-onset cutaneous mastocytoma is a rare entity described in less than 20 patients so far [ 1 ] . Its diagnosis is challenging as it may be confused with a vast spectrum of diseases according to its clinical presentation. Indeed, it may appear as a macule, papule, plaque or nodule and vary in color from yellow to brown, to red [ 2 ] . Dermoscopically, cutaneous mastocytoma has been reported to present a yellow-orange blot pattern [ 2 ] . Anyway, in our case, an irregular vascular pattern exclusively characterized by irregular linear and serpiginous vessels of steady caliber, on a pink-red background and perifollicular scar-like white areas were observed. More data are needed since reported dermoscopic descriptions are very scant. Given that the onset of cutaneous mastocytosis in adults is frequently associated with systemic disease, it has been recommended that the initial diagnostic work-up should include blood tests ( complete blood cell count, serum chemistries with liver function tests, and sT levels), and also bone marrow biopsy (BMB) [ 2 ] . If there is no systemic involvement, all the above-mentioned investigations apart from BMB, should be repeated yearly [ 2 ] . In our case, due to the absence of systemic symptoms and normal sT, BMB was not performed. Concerning treatment, surgical excision is the most employed one, followed by topical or intralesional corticosteroids [ 2 ] ; other treatments comprise pimecrolimus and pulsed dye laser therapy [ 2 ] .
We reported the unusual case of adult-onset facial mastocytoma, arising on the forehead, and described new dermoscopic findings. Although the strength of our observation is limited by the single patient, we believe that enriching literature with new information may contribute to improve diagnosis of unusual manifestations.
- Dermoscopic features of skin lesions in patients with mastocytosis Vano-Galvan S, Álvarez-Twose I, De Las Heras E, et al. Arch Dermatol.2011;147(8):932-940. CrossRef PubMed
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