port - wine stains ( pwss ) are congenital vascular malformations comprised of ectatic dermal capillaries and affecting 0.3 - 1% of newborn infants . acquired pwss are an uncommon entity developing later in life , but morphologically and histologically similar to the congenital lesions . we hereby report a case of 41-year - old male patient who acquired pws about a year ago . a 41-year - old male presented to the outpatient department of dermatology of our tertiary care hospital with complaint of asymptomatic reddish patches involving the lower part of right leg for 10 months . the patch started from near the ankle and gradually spread to involve whole of the medial aspect of right leg over a period of 10 months . we could not elicit any history of antecedent mechanical or thermal trauma , drug intake , topical application or excessive ultraviolet exposure . dermatological examination revealed a diffuse partially blanchable erythema extending from the right ankle and involving chiefly the medial aspect of right leg up to the knee [ figure 1 ] . there were also a few discrete irregularly shaped partially blanchable reddish - purple macules present on the anterior aspect of right leg [ figure 2 ] . a diffuse partially blanchable erythema extending from the right ankle and involving the medial aspect of right leg up to the knee discrete irregularly shaped partially blanchable reddish - purple macules present on the anterior aspect of right leg on the basis of the clinical examination , a provisional diagnosis of acquired pws was made and the patient investigated . the histopathological examination revealed multiple dilated , variably sized capillaries lined by a single layer of endothelial cells throughout the dermis showing lobular arrangement at places [ figure 3 ] . color doppler of the limb did not reveal any abnormality of the underlying arteries and veins . ( a ) multiple dilated variably sized capillaries in the dermis ( h and e , 40 , arrows ) . ( b ) high power showing groups of capillaries lined by a single layer of endothelial cells ( h and e , 250 , arrow ) laser therapy was discussed with the patient , but he declined treatment for the lesion . pwss are congenital vascular malformations usually presenting at birth in the form of pink - red to purple macules , which become darker , raised , and nodular as the person ages . the most accepted hypothesis is a defective embryological maturation of the sympathetic fibers , resulting in a loss of normal sympathetic control of the cutaneous vessels which leads to ectasia . various factors have been proposed for the occurrence of acquired pwss . of these , trauma has been found to be the most important causative factor in majority of the cases . trauma - induced pws was first described by fegeler in 1949 and hence called fegeler syndrome . in a review of 59 patients with acquired pws , trauma was found to be a causative factor in 17 ( 29% ) cases . it has been proposed that injury may result in loss of a previously effective sympathetic regulation of the cutaneous blood flow , leading to development of the lesions . reports of acquired port - wine stain few cases of acquired pws have also been proposed secondary to oral medications like isotretinoin , oral contraceptive pills , simvastatin , and metformin . isotretinoin causes skin fragility and frictional trauma , while simvastain and metformin have been shown to promote angiogenesis by upregulation of vascular endothelial growth factor . isolated cases of acquired pws following frostbite injury , obstruction of the peritoneovenous shunt , herpes zoster infection , cerebral arteriovenous malformation , spinal root compression , and solid brain tumor have also been reported . no definite cause was found for the development of lesion in our patient . in such cases , a likely possibility of having a latent vascular anomaly which manifests clinically after unnoticed trauma an unusual finding in our patient was the presence of a lobular arrangement of dilated vessels in the dermis which has not been observed in previous cases of congenital or acquired pws . interestingly , there are multiple reports of development of pyogenic granulomas ( pg ) within pws which also shows a lobular pattern of dilated vessels . it has been proposed that the pg probably results from an underlying arteriovenous anastamosis frequently associated with the pws . though , there was no clinically appreciable pyogenic granuloma like lesion , the distinct histological features seen in our patient might be attributed to a similar pathogenetic mechanism . as regards therapy , it includes treatment with krypton , argon , argon - pumped , tunable dye , neodymium : yttrium - aluminum garnet , copper vapor , and pulsed dye lasers . acquired pws tends to have a quicker and better response to pulsed dye therapy than congenital pws . the case report demonstrates a rare occurrence of a vascular malformation in an adult patient . although no definite cause could be appreciated for the development of lesion in our patient , further reports and future insights into the pathogenesis of such cases would broaden our knowledge regarding this infrequently reported phenomenon . this is the first report of an acquired port - wine stain from india and previous reports of such cases have also been reviewed .
port - wine stains ( pwss ) are congenital vascular lesions caused by progressive ectasia of blood vessels located in the vascular plexus of the dermis . 
 acquired pwss develop later in life but are identical in morphology and histology to the congenital pwss . 
 less than 75 cases of acquired pwss have been reported in the published literature , of which there has not been a single report from india so far . 
 various factors have been proposed for its pathogenesis like trauma , actinic exposure , drugs , tumors , and herpes zoster infection . 
 we report an acquired port - wine stain in a 41-year - old male . 
 the causative factors , treatment , and previous reports of this uncommon entity have also been reviewed .