we read with interest a case series of acquired port wine stain (PWS) in 3 otherwise healthy children (2 females and 1 male) by Millán-Cayetano et al.1 published in Actas Dermo-Sifiliográficas journal. The authors stated “acquired capillary malformation may be considered simply to be a late-onset capillary malformation with a variable latency period”. Actually, acquired PWS is not as “simple” as considered by the authors. The authors underestimated skin diseases masquerading as PWS.

Linear morphea is a form of morphea that can affect an entire extremity and follow the lines of Blaschko. Children are more likely than adults to have linear morphea on the face.2 In many cases, the affected skin is initially erythematous and may resemble a PWS. Vascular damage, such as microvascular injury, and T-cell activation, with subsequent abnormal collagen production by fibroblasts, is thought to be involved in its pathomechanism.3 Nihjawan et al.4 reported four cases that had presented with erythematous vascular-appearing patches resembling PWS. Three lesions were located on the face and one was on the leg. The initial biopsies of two patients revealed telangiectatic dermal vessels, consistent with PWS. However, further biopsies revealed dermal fibrosis with patchy lymphocytic infiltrate, consistent with morphea. Diagnosis of morphea was made approximately 6 months to 3 years after the onset of the acquired PWS. On the other hand, perineural inflammation has rarely been reported to be an early histopathological feature of morphea.5 Singh et al.6 reported 2 cases of morphea with subtle sclerotic changes initially, presented with perineural and intraneural lymphoplasmacytic infiltration. According to Nihjawan et al.,4 there was prominent perineural inflammation which prompted the diagnosis of early morphea. In other words, early inflammatory morphea can present initially with a vascular, nonindurated patch.7 Biopsies of these lesions may not reveal the characteristic features of established morphea and the diagnosis has to be considered if perineural inflammation is seen.4 Nihjawan et al.4 recommended, in patients with acquired PWS, delaying PDL treatment until a diagnosis of early morphea can be excluded.4 However, it is difficult to ascertain whether laser therapy to the initial lesions triggered the increase in fibrosis as some of the reported cases did not receive laser treatment.7 Treatment of PWS using the PDL may reduce the skin erythema, but did not prevent subsequent sclerosis.

To sum up, acquired PWS is not a simple stain. Inflammatory morphea should be considered in the differential diagnosis whenever an acquired PWS has been identified, especially on the face.2 Early stages of morphea are sometimes difficult to recognize, and histology may not helpful in early cases because there is overlap, leading to misdiagnosis. Clinicopathological correlation is of paramount importance in such cases. Morphea should be considered if perineural inflammation is seen in histopathology. Dermoscopy can assist in the early diagnosis of localized scleroderma (LS), with no need for invasive examinations.8 Noteworthy, ultrasound used for LS has demonstrated clear differences from healthy skin and improvement after initiation of treatment.9