pachyonychia congenita ( pc ) is a group of rare , inherited ectodermal dysplasias associated with mutations in keratin genes of k6a , k6b , k16 or k17 . the most prominent clinical features of pc are nail dystrophy and dyskeratosis of skin and mucous membranes . pc was first described by muller in 1904 and wilson in 1905 ; although , the association of the disorder with palmoplantar keratoderma and other ectodermal defects was reported by jadassohn and lewandowsky in 1906 . common to almost all patients who have been described , regardless of the form of inheritance or subclassification of the disorder , is the onset in infancy . very few cases have been reported so far with late onset and considered as a rare variant of pc . the term pachyonychia congenita tarda ( pct ) has been suggested to describe this late onset form of pc . it is characterized by nail dystrophy , palmoplantar hyperkeratosis , leukokeratosis of mucous membranes , follicular hyperkeratosis , hyperhydrosis of palms and soles . we herein report one such rarer case with oral leukokeratoses and angular cheilosis as components of the same syndrome . a 45-year - old male patient was referred from department of dermatology , government district hospital for examination of whitish lesions in the mouth . history of present illness revealed that oral lesions along with thickening of nails and callosities on palms and soles were present since 10 years of age . his family history revealed that his father , brother and son have a similar condition , but declined clinical examination . nails were extremely hard , thickened , opaque brown , lusterless and free edges were raised by a thick horny masses of subungual keratosis . solitary right and left submandibular lymph nodes were palpable , 1 cm  1 cm , mobile and firm . labial mucosa , ventral surface of tongue , floor of the mouth , vestibular mucosa and oropharynx revealed no abnormalities . leukokeratosis characterized by diffuse whitish , non - tender and non - scrapable plaque such as lesions of the both right and left buccal mucosae [ figure 2 ] , left retromolar region [ figure 2 ] , dorsal aspect of the tongue [ figure 3 ] , hard and soft palate and gingivae [ figure 4 ] were present . leukokeratoses of buccal mucosae and retromolar region leukokeratoses of tongue leukokeratoses of the palate and gingivae all routine investigations such as complete hemogram , urine analysis and fasting blood sugar were within the normal limits . incisional biopsy was carried out on the left buccal mucosa and histopathological features were suggestive of oral leukokeratosis [ figure 6 ] . histopathological features suggestive of leukokeratoses based on the characteristic clinical presentation and history , a diagnosis of pct was made . for symptomatic treatment of extraoral lesions the patient was referred to the department of dermatology , government district hospital where he was put on oral vitamin a , keratolytic agents and emollients . the present case reports a patient with pct as characteristic clinical changes had started in the second decade of life . though dystrophy of all nails is the main feature of the syndrome and usually presents within the first month of life , recently few patients have reported with the onset of the characteristic nail changes during the second and third decades of life . the term pct was proposed to describe this rare subset of pc , representing exceptions that result from mutations elsewhere in the keratins 16 and 17 genes . the inheritance pattern of our case is highly suggestive of an autosomal dominant mode of inheritance as his father , brother and son have a similar condition and therefore consistent with the other families with pct described . in classical pc hypertrophy and distortion of nails , hyperkeratotic skin lesions , such as palmoplantar keratoderma , follicular keratoses , varicosities over knees , elbows , buttocks and popliteal area and oral leukokeratoses , other associated features , which may occur include bullae on palms and soles , hyperhidrosis of the palms and soles , natal or neonatal teeth , angular cheilosis , steatocystoma multiplex , hair anomalies , alopecia , corneal dyskeratosis , hoarseness , laryngeal lesions , cataract , polydactyly and mental retardation . these above mentioned clinical manifestations may vary and or could overlap as it is in our case . the case reported here has angular cheilosis in the type i pc ( jadassohn - lewandowsky syndrome ) . this could be because of pc has both autosomal dominant and autosomal recessive modes of inheritance with variable penetration , reflecting genetic heterogeneity.- complications like respiratory distress due to laryngeal leukokeratosis and acroosteolysis and malignant changes in palmoplantar lesions can occur in pc . hence , patients with pc should be thoroughly investigated and treated accordingly as early as possible . when familial mutation is known , genetic counseling and if required , prenatal diagnosis can be performed at the early stage of pregnancy , enabling new options for suitable therapeutic regimens . it even offers the hope of curing such type of skin diseases by means of somatic cell gene therapy . there are no reports available at the moment on the specific therapy of pct . in classical pc , retinoids , oral vitamin a , keratolytic agents , emollients and surgery have been reported to be effective in alleviating some signs and symptoms of the disease . the ideal solution for a permanent cure for pc would be a gene therapy replacement procedure in which the defective pc gene would be replaced with a corrected version that would be regulated in identical fashion to the wild type gene . the classical as well as late - onset variants of pc are characterized by heterogeneity in expression of a number of associated features . it seems rational to distinguish pct from pc by the differences in age of onset . dentists should be able to recognize this condition in its early stages and advice appropriate investigations and management as dentists may be the first to see and diagnose this condition .
pachyonychia congenita is a rare , but well - characterized autosomal dominant disorder of keratinization . 
 it usually begins within the first few months of life . here , we are presenting a rare case , which started at the age of 10 years of life and is known as pachyonychia congenita tarda . 
 the case is being reported for its rarer occurrence as the patient had oral leukokeratosis and angular cheilosis present in the same type of the syndrome ( jadassohn - lewandowsky syndrome ) , which is still uncommon .